| Action Date |
Action |
Description |
DEC Staff |
| 10/20/1989 |
Update or Other Action |
ADEC Ron Klein, Supervisor, Contaminated Site Investigations, sent letter to Captain Brad Gerken, Dept. of Air Force, 5099th Civil Engineering Operations Squadron (AAC) Subject: Response to September 27, 1989 Letter; Requirements for Temporary Storage of Petroleum Contaminated Soil.
Enclosed is a copy of the Southcentral Region Office's interim policy for storage and disposal of waste oil contaminated soil.
The guidance also applies to storage of soils contaminated with clean fuels if they are to be stored off the site where they were generated or stored on-site longer than thirty (30) days. The guidance document will be revised shortly to make that explicit. Petroleum contaminated soils generated on-site and stockpiled onsite for less than thirty (30) days must be placed on a bermed liner and covered. The liner and cover must be at least 6 mil reinforced polyethylene.
Alaska Department of Environmetal Conservation Southcentral Region Office - Interim Policy For Storage and Disposal of Waste Oil Contaminated Soil
The Southcentral Regional Office solid waste program has been working on an interim policy for storage and disposal of waste oil contaminated soil. Currently the Region has approved the removal of waste oil contaminated soil to a facility permitted to properly handle the contamination. With the exception of the Municipality of Anchorage (MOA) Landfill and Alaska Pollution Control Palmer Facility (pre-treatment for landfill disposal) all of these
facilities are located in the contiguous United States.
Currently, if the waste oil contaminated soil does not meet MOA Landfill criteria the only disposal option is to send the contaminated soil out of Alaska. Soil disposal under this method is costly due to handling, shipping, and facility fees. In discussions with Responsible Parties (RP) there appears to be a strong move to develop other local disposal methods that would meet with agency approval. Therefore the Regional solid waste program has developed interim storage guidelines for waste oil contaminated soils.
These guidelines include the following:
1. An approved design for a low-maintenance or maintenance free storage liner and cover that will be able to withstand winter conditions and is petroleum resistant. This will include a schedule to monitor the storage facility to verify that the integrity of the liner and cover is maintained through out the storage period.
2. Obtain a solid waste storage plan approval for onsite storage of waste oil contaminated soil from ADEC prior to storage construction.
3. The Responsible Party may propose to remove the waste oil contaminated soil to an off-site storage location if long term on-site storage is not practical. This location must be approved of by the Department prior to any transfer of the soils. The storage site must meet, ADEC design criteria and the RP must obtain an off-site; solid waste storage plan approval prior to transfer of the soil. All transfer of soil off-site must be done under a Bill of Lading and copies provided to ADEC.
4. The maximum allowable storage time is one (1) year. |
Ron Klein |
| 4/16/1990 |
Update or Other Action |
USEPA Memorandum Subject: Elmendorf AFB Deliverables and Operable Units (OU) from Doug Johnson Environmental Scientist, AOO/A to George Hofer Chief Federal Facility Branch HW-074.
The following is a synopsis of two meetings that were held with staff members of ADEC and EPA. The first meeting was held on April 6, 1990 and the second was held on April 12, 1990. Attendees for the meetings from ADEC were Ron Klein, Max Schwenne, Colleen Burgh, Jennifer Roberts with Mary Siroki and Geoff Kany attending the first meeting.
The following reflects the input from ADEC regarding the document deliverables, determination of operable units, and schedules for inclusion to the Elmendorf AFB Interagency Agreement. This information was discussed with Bob Loiselle during your absence.
Document Deliverables: It was determined by mutual agreement that the same document deliverables now proposed for the Eielson IAG be incorporated into the Elmendorf IAG without change. ADEC agrees that for consistency and simplicity reasons the document deliverables for all Alaska IAG's remain the same.
Operable Units: Operable unit determination was based upon a hierarchy which was derived by either geographic or site characteristic similarities. The listed order was determined by severity of contamination (worst first) based upon common knowledge of the meeting participants.
Operable Unit #1 (Million Gallon Hill Area)-Sites SP-5/5A, OT-1, D-15, D-16, D-17, NS-2.
Operable Unit #2 (Air Force High Priority Sites-Sites S-5, D-4, D-10, FT-1
Operable Unit #3 (Landfills)-Sites D-5, D-6, D-7, D-8, D-9, D-11, D-12, D-13, NS-2
Operable Unit #4 (Hangar Floor Drains)-Sites IS-1, IS-2, IS-3, IS-4, IS-5, IS-6, IS-7, IS-8
Operable Unit #5 (Fuel Spill Sites)-Sites SP-1 thru SP-16, NS-3
Operable Unit #6 (UST/LUST Sites)-Approx. 35 known UST/LUST sites scattered around facility.
Operable Unit #7 (Misc. Sites)-Sites D-1, D-2, D-3, RD-1, S-l, S-3, S-4, S-6, S-7 [NOTE TO FILE: new IRP# for S-7 is SS22 DRMO Storage Area - South of Davis Highway also known as Area "D", is the future storage site]
Please note that of these operable units, the first three are probable definites for inclusion to the IAG. The last four have been included at this stage for discussion purposes and for understanding the perceived universe of sites at Elmendorf AFB.
Further refinement of this list and determination of schedules to be discussed on May 2, 1990 with ADEC. I will continue to discuss this subject with Bob as it develops, and would welcome any input you might have. |
Jennifer Roberts |
| 7/26/1993 |
Update or Other Action |
Drinking water system no. AK2218476 for USAF Elmendorf - Naval Security Group, Active system serving 30 individuals year around. |
Louis Howard |
| 1/20/1994 |
Enforcement Agreement or Order |
Janice Adair Regional Administrator Southcentral Regional Office signs the November 29, 1993 Underground Storage Tank Agreement. The Parties enter this Agreement to perform necessary inventory, registration, upgrading or closure, and tightness testing associated with USTs at Elmendorf. All draft final work plans for field work must be submitted to ADEC a minimum of 30 days prior to the start of field work or construction. Site Assessment draft reports for closures must be submitted to ADEC within 60 days after completion of field work.
All reports of confirmed leaking USTs, or the need for further investigation, will be forwarded to 3 SPTG/CEVR (or its) successor organization) for possible inclusion into the SERA*. Initial abatement activities required under 18 AAC 78.230 will be conducted by the Air Force prior to transfer of any site to the SERA.
*SERA=Environmental Restoration Agreement between ADEC and the Air Force dated October 1992.
Discovered USTs-All USTs discovered during the life of this Agreement will be addressed under this Agreement and will be added to Attachment A. The Air Force will notify ADEC by next day mail of any discovery within five days of the discovery of an UST, unless release notification is required under 18 AAC 78 220, in which case those provisions will control.
Installation: Any new USTs installed by the Air Force shall be installed in accordance with 40 CFR 280 and 18 AAC 78.022 through 18 AAC 78.090 and will have leak detection, corrosion protectlon, overfill protectIon, and spill protection. The Air Force will notify ADEC at least 30 days prior to initiating installation of an UST. UST installation work will be conducted by a certified UST worker as required by 18 AAC 78.030 and 18 AAC 78.400.
Release Detection: The Air Force shall install and perform release detection in accordance with the schedules outlined in Attachment A. If release detection is not installed or the tank not previously permanently closed by the date in Attachment A, the Air Force will close the tank in accordance with the closure requirements in 18 AAC 78. All tightness testing performed to satisfy these requirements will be conducted bv a certified UST worker as required bv 18 AAC 78.030 and 78.400
Operation and Maintenance of Corrosion Protection: The Air Force shall meet the requirements of 18 AAC 78.045 and 40 CFR 280.31 for any steel USTs, that have corrosion protection systems The testing of the corrosion protection systems shall be done by a certified UST worker as required by 18 AAC 78.400.
Site Assessment or System Tig:htness Test: The Air Force shall either conduct a system tightness test on all regulated USTs located at the Base or permanently close the USTs in accordance with Attachment A. If site assessments or system tests have been conducted, the Air Force shall submit proof of compliance by the deadlines set in Attachment A. All tightness testing work will be conducted by a certified UST worker as required by 18 AAC 78.400.
Release Investigation and Corrective Action: Release investigations, interim corrective action and corrective action on petroleum contamination identified in work conducted pursuant to this Agreement is not within the scope of this Agreement. These activities will be conducted pursuant to the Environmental Restoration Agreement between ADEC and the Air Force dated October 1992. |
Janice Adair |
| 4/18/1995 |
Update or Other Action |
AF memo: 18 April 1995 Underground Storage Tank (UST) Meeting. Elmendorf AFB will accomplish the following actions regarding UST Projects. These actions are based upon conversation between, John Mahaffey, Larry Opperman and yourself. EAFB will make every effort to accomplish a clean closure of a UST removal site if possible. UST removal locations requiring cleanup action will be transferred into the State-Elmendorf Environmental Restoration Agreement (SERA). A list of sites requiring cleanup will be coordinated with your office.
The presumptive remedy for contaminated UST sites in the outwash plain only will be bioventing technology. Contaminated soils exceeding cleanup levels may be placed back into the excavation only if the site assessment (SA) indicates a need for further cleanup action. Contaminated UST sites not in the outwash plain will require further investigation to determine appropriate cleanup options. We will make every attempt possible to assure new USTs or new aboveground tanks are not installed in any way that would hamper future access for cleanup. The project will first accomplish removal of all of the USTs. SA information will be used to prioritize sites for cleanup using existing project funds.
Additional funding will be requested to complete cleanup if available. Sites not addressed for cleanup due to exhausted funding will be placed into SERA Phase IV. John Halverson signed on April 21, 1995. Memo was signed by Douglas G. Tarbett, Maj, USAF, Chief, Environmental Compliance. CC: 3 WG/JA and 3 SPTG/CE. |
John Halverson |
| 8/14/1995 |
Document, Report, or Work plan Review - other |
On February 21, 1995, staff sent the Air Force a letter with comments on site assessment reports prepared by EA Engineering for underground storage tank systems (USTs) it closed or upgraded during 1994. The reports were not complete and ADEC requested they be amended to provide the necessary information. Without the complete site assessment reports ADEC is unable to make determinations on site closure or the need for additional investigation or corrective action. Until information is submitted, the Air Force has not met its site assessment obligations and may be in violation of release investigation and corrective action requirements.
On March 28, 1995, ADEC sent the Air Force another letter providing comments on site assessment reports prepared by Haliburton NUS and Harding Lawson. Several of the sites may be appropriate for no further action decisions after additional information is provided. However, until it is submitted, ADEC cannot make such determinations.
The 1994 UST tightness testing results report, dated January 1995, identified the following problems: Tank#755 at building 76-527 failed tightness tests. ADEC has not received site assessment or release investigation reports for this site. |
John Halverson |
| 11/11/1995 |
Update or Other Action |
1995 UST Decommissioning & Site Assessment-Building 18224 at DP98 was previously referred to as ST423 under the SERA program for the investigation of USTs. No longer used for vehicle maintenance, Building 18224 is used to support operations of Building 18220. ST423 was included in the SERA Phase IV release investigation because of high concentrations of diesel range organics (DRO) detected in the soil.
Diesel used to fuel an emergency generator & was stored in a 3,000 gallon tank located at the southwest corner of the building.
Based on field PID screening & laboratory DRO analysis of soil samples collected from the UST AFID 755, 381st IS site, ACCI has prepared the following conclusions & recommendations.
On October 16, 1995, UST AFID 755, located at the 381st IS, was removed. Field PID screening & laboratory analysis indicated that approximately 65 cubic yards of soil excavated during the UST removal were contaminated with diesel range organics. The contaminated soil was transferred to Alaska Soil Recycling for thermal remediation. A new, 4000 gallon, UST was installed in the excavation & clean, uncontaminated soil was hauled, placed, & compacted to restore the site to its original grade.
Lab analyses of four soil samples obtained from UST AFID 755 381st site produced DRO concentrations ranging from 42 to 9,700 mg/Kg (Table 1). These DRO concentrations exceed the ADEC clean-up limit of 200 mg/Kg established for a "level B" site clean-up . They indicate that clean closure cannot be obtained & that remediation is required for this site. ACCI recommends exploring thermal, intrinsic, or bioventing remediation programs for the AFID 775 381st site.
Thermal remediation would involve excavation & removal of contaminated soil from this site to two stockpiles. Field screening of soil during excavation would be accomplished using a PID meter. Soil displaying no response on the PID meter would be placed in a "clean" stockpile.
Soil displaying PID readings above non-detectable limits would be placed in a "questionable" stockpile & soil samples from both stockpiles would be analyzed to accurately determine contamination levels. Excavation would continue until the PID meter indicated all contaminated & "questionable" soil was removed from the ground. Contaminated soil could then be remediated through burning by a qualified contractor. Only clean, non-contaminated soil I would be used to backfill the excavation.
If the contaminated soil cannot be safely or economically removed from the site, intrinsic remediation should be considered. This technique is best suited for total petroleum hydrocarbon (TPH) levels lower than 25,000 PPM at sites that are far from potential receptors. The site must be evaluated for soil permeability, pH, moisture content, nutrient levels, elevation, grade, & distance to the nearest active well. A long-term commitment will be required to adequately monitor the progress of intrinsic remediation.
A 25,000 gallon diesel UST located directly northeast of the new tank was emptied & abandoned in place. The adjacent UST should be pressure tested to ensure an ongoing hydrocarbon release is not occurring from this. If the adjacent UST fails the pressure test, ACCI recommends removal & replacement of this tank. A remediation plan can then incorporate site assessment results from both sites. |
Louis Howard |
| 3/15/1997 |
Update or Other Action |
SERA Phase IV UST Closures Investigation Report: ST423 consists of UST AFID 775, a former 3,000 gallon steel UST located west of Bldg. 41-755. The UST was used to store diesel fuel for the emergency generator at 41-755.
Petroleum hydrocarbons, primarily DRO, were detected in soil at levels exceeding cleanup criteria in samples collected from 13 soil borings installed at the site in 1996. BTEX and DRO were also detected in groundwater samples collected from site wells installed in soil borings. Due to the presence of contaminated groundwater above cleanup levels, the site cleanup level was upgraded to a Matrix Score Level "A" under 18 AAC 75. Volatile organic compounds (VOC) were not included in the sample suite during the 1996 investigation.
No bioventing treatability study was conducted at the site due to the presence of free product on the groundwater and the site silty soils with low apparant air permeability. Floating hydrocarbon fuel was detected in one well (41755-WL01) adjacent to the former UST and in a second well (41755-WL03) located about 150 feet north-northwest of the former UST.
A passive product recovery system was installed in 41755-WL01 and operated from April through December 1996. Only three and a quarter (3 1/4) gallons of fuel product was removed from the well during that time.
Conclusions: Petroleum hydrocarbons, principally diesel range, were detected in the soil at ST423. Groundwater contamination was identified. The spatial extent of the soil and groundwater contamination has been delineated. Contamination appears to have migrated along zones of high hydraulic conductivity. The downgradient extent of the contamination does not extend beyond wells 41-755WL06 through -09. Free product was identified on aquifers at the site.
The initially determined ADEC Level B cleanup goal for ST423 is not supported by the SERA IV release investigation as groundwater contamination was identified. No matrix score was calculated for ST423 as Level A cleanup is required for sites at which groundwater contamination is detected.
It is recommended that USAF consider alternate remedial strategies for the soil and groundwater contamination detected at ST423. Bioventing is not likely to be successful due to the presence of free product, fine-grained soils, and extensive subsurface preferential airflow pathways. |
Louis Howard |
| 11/11/1997 |
Update or Other Action |
SERA Phase VI investigation: A passive soil survey was conducted in 1997 to delineate the extent of fuel constituents in shallow soil . Results indicated two discontinuous areas of possible fuel contamination: one area approximately 1,000 feet northwest of Building 18224 and another approximately 430 feet northwest of Building 18224. Four samples were analyzed for VOCs and semivolatile organic compounds (SVOC). DRO was detected in all samples with residual range organics (RRO) found in one of the soil borings samples. Total petroleum hydrocarbons and GRO were detected in both surface soil samples. Groundwater samples from four downgradient wells installed in 1996 (417550-WL06 through 41755-WL09) were analyzed for VOCs. Dichloroethene (DCE), 1,1,1-trichloroethane*, and TCE** were detected in one well (41755-WL08); TCE concentrations exceeded ADEC cleanup levels. One surface water sample collected from a local pond was analyzed for VOC and SVOCs; only DCE was detected.
NOTE TO FILE: 1,1,1-trichloroethane (TCA) was first prepared in 1840, but was not used in significant commercial quantities for over 100 years. It was first introduced commercially in the US by Dow Chemical in the mid-1950s. TCA's early uses were in cold cleaning applications and as an aerosol propellant. As a propellant, TCA was used in a variety of products including hair sprays. Despite its effectiveness as a cleaning solvent and its significantly reduced toxicity relative to TCE, TCA took many years to gain acceptance in the vapor degreasing market because it was relatively unstable, particularly in the presence of aluminum and when subjected to high temperatures. TCA was not widely used until improved stabilizer formulations were developed and implemented in the late 1950s and early 1960s. These stabilizer formulations used several chemicals, chief among them being 1,4-dioxane, to overcome TCA's corrosion problems. As a result of improved TCA stabilizers and the regulation of TCE as an air pollutant, the production of TCA surpassed TCE in 1973.
TCA, along with CFCs and other chemicals, were identified as ozone-depleting substances in the mid-to-late 1970s. Aerosol propellants were banned in the US in 1978. The 1990 Clean Air Act Amendments imposed a December 1995 deadline for ending emissive uses, and included other interim deadlines and schedules that significantly decreased TCA use. Dow Chemical ceased TCA production in February 1994.
**Trichloroethylene (TCE) became one of the most widely-used chlorinated solvents for cleaning and degreasing because of its effectiveness, noncorrosivity, and nonflammability. TCE was first prepared in 1864, but was not produced commercially in the US until the 1920s. Earliest applications included use in boot polishes and printing ink dryers. TCE was used in the US food processing industry as an extraction solvent as early as 1927. During the 1930s, TCE's use in the dry-cleaning industry increased, and it began to replace carbon tetrachloride in solvent applications.
During World War II, the production and use of TCE increased significantly due to its use in degreasing. Supplies were controlled by the US government so that military demands could be met. The introduction of neutral stabilizer systems in 1954 helped retain TCE's position as the degreasing solvent of choice. It did, however, have other uses at this time, including dry-cleaning, and extraction of fats and oils. It was also used as a heat exchanging fluid, and in medical applications as an analgesic and anesthetic. DuPont was the largest producer of TCE in the late 1950s.
TCE became the first chlorinated solvent to be subjected to environmental regulation when the Los Angeles County Air Pollution Control District enacted Rule 66, which limited air emissions of TCE and other smog precursors. The use of TCE peaked in the US in 1970. Its decline in the following years was primarily due to increased evidence of toxicity and the advent of environmental regulations. The National Cancer Institute released evidence of TCE carcinogenicity in March 1975; in July 1975, General Foods ceased using TCE for decaffeination of coffee.
TCE use increased during the 1990s when TCA and other solvents were banned under the 1990 Clean Air Act Amendments. (TCA is discussed further below.) Dow Chemical and PPG were the remaining TCE producers as of 1997. |
Louis Howard |
| 12/30/1998 |
Update or Other Action |
Three soil borings were installed as a part of the SERA Phase VII investigation within the DP98 site around Building 18224. They were analyzed for petroleum fuel compounds to fill data gaps left by the previous SERA investigations. DRO, GRO, BTEX compounds were detected, with DRO concentrations exceeding the ADEC cleanup level. |
Louis Howard |
| 12/31/1998 |
Update or Other Action |
Quarterly progress report. DP98 is located in the northwestern portion of the base. The site is northwest of Building 41-755. Building 41-755 is in a restricted access area.
SUMMARY OF CLEANUP ACTIVITIES-During a State-Elmendorf Environmental Restoration Agreement (SERA) investigation related to underground storage tanks, soils and groundwater in the area
found to contain fuel-related contamination and some chlorinated solvents, including 9.9µg/L trichloroethene (TCE) in one well, which is above the proposed state standard of 5µg/L. The concentrations of the constituents of potential concern other than TCE were found to be below the state of Alaska’s proposed cleanup standards for groundwater.
|
Louis Howard |
| 6/30/1999 |
Update or Other Action |
June 1999 Quarterly Progress report: DP98 is located in the northwestern portion of the base. The site is northwest of Building 18224. Building 18224 is in a restricted access area. The source of solvents is not fully defined, but results indicate it may be associated with Building
18224. Review of as-built drawing for Building 18224 showed an area used as a garage in part of this building. The solvent contamination is believed to be the result of Air Force personnel doing vehicles maintenance in this facility during the last half of the 1950s.
|
Louis Howard |
| 2/28/2000 |
Update or Other Action |
SERA Phase VIII- Soil samples were collected from soil boring 423-BH05 adjacent to existing well 21755-WL04 and analyzed for fuels and VOCs. Soil collected from 22 feet bgs contained TCE, cis-1,2-DCE, above ADEC cleanup levels. Groundwater was collected from 12 monitoring wells (41755-WL01 through 41755-WL12) for DRO, GRO, VOCs. DRO, GRO, and benzene were detected at concentrations exceeding ADEC cleanup levels. TCE, DCE, 1,1-DCE, tetrachloroethylene (PCE) and vinyl chloride (VC) were also detected at concentrations exceeding ADEC cleanup levels. Well 41755-WL02 (12-Nov-1999) had maximum concentration of PCE at 2,800 ug/L. Well 41755-WL04 had maximumum concentration of TCE 5,000 ug/L and 1,1-DCE at 9.4 ug/L. Well 41755-WL05 had cis-1,2-DCE maximum detected at 5,700 ug/L, trans-1,2-DCE at 37 ug/L and vinyl chloride at 9.6 ug/L.
Release of TCE, PCE, Cis-DCE were attributed to historic maintenance and cleaning operations which likely concentrated in the drain tile area.
These results made it apparent that a more intrusive and larger scale investigation was necessary to better determine all possible sources of contamination and determine the nature and extent of fuel and VOC contamination. |
Louis Howard |
| 5/3/2000 |
Meeting or Teleconference Held |
Engineering Evaluation/Cost Analysis (EE/CA) for TCE contamination at DP-98 Elmendorf AFB meeting minutes for May 3, 2000 meeting.
Significant decisions and the main issues discussed are listed below:
1. Security concerns at DP98.
* The Air Force representatives discussed security. Contact names and numbers were
provided and a list of information needs was given. Advance notification should consist of 2 weeks notice of equipment to be used, locations to be accessed, a tentative schedule with working hours, and a list of staff to be on site.
Several areas were identified as "escort only" zones and these areas will be reviewed again prior to the commencement of field work.
2. Overview of Initial Field Screening Task
* Radian/URS described the history of Site DP98 and presented their proposed field approach to initially delineate the lateral extent of chlorinated solvent contamination in soil via passive soil gas monitoring.
* AFCEE and the Air Force agreed to provide an expeditious review of the draft workplan in order to allow for field work to start during the month of May.
3. Project Start-up
· A preliminary site walk-through is tentatively scheduled for the week of May 8-12, 2000.
· An official kick-off meeting with the Contracting Officer (CO) and Contracting Officer Representative (COR) will be held following preliminary review of the draft work plan.
The kick-off meeting will serve as the notice-to-proceed and begin the field program.
· It was recommended that an agency meeting be held to discuss the overall field approach and objectives of this program. The agency meeting would primarily focus on the characterization approach and objectives, and remedial action alternatives.
· Natural attenuation with possible monitoring would be the preferred alternative. Toward this goal, natural attenuation parameters will be evaluated from all media samples collected.
· To improve upon previous interpretations of current groundwater flow direction at the site, water level measurements will be performed and supplemented with geochemistry data in the form of common groundwater ions. |
Louis Howard |
| 6/1/2000 |
Site Added to Database |
Site added. |
Louis Howard |
| 6/19/2000 |
Document, Report, or Work plan Review - other |
ADEC comments on the Draft DP98 TCE investigation WP.
1.5 Project Objectives Page 1-7
DEC questions whether the field screening proposed in the document is able to determine the level of contamination. The main purpose of conducting field screening is to use the results to determine where samples will be collected. Field screening results may also be used to segregate soils, based on apparent levels of contamination, to help monitor potential exposures, & for health & safety monitoring. However, field screening may not take the place of laboratory samples required to determine the level of contamination. There are two levels of field screening procedures:
(1) use of field screening devices to perform synoptic surveys of potentially contaminated areas to determine the approximate locations containing contaminants (qualitative screening); &
(2) use of field screening devices to provide a semi-quantitative estimate of the amount of contaminant present at a specific location (semi-quantitative screening).
Table 1-1 under “parameters of concern” does not list laboratory confirmation sampling for volatile organic compounds (VOCs) such as TCE, PCE & trichloroethane which are the main focus of this work plan. DEC requests the table be revised to include VOCs under laboratory confirmation sampling.
3.0 Applicable or Relevant & Appropriate Requirements Page 3-1
Strike reference to ADEC Interim Guidance for Surface & GW Cleanup Levels (September 26, 1990) since it has been superseded & replaced by 18 AAC 75 & 18 AAC 70.
3.1 Water Quality Criteria Page 3-2 & Table 3-1 Pages 3-3 & 3-4
The text refers to a guidance document (see comment above for section 3.0) that has been replaced & TPH levels that are no longer used as cleanup levels. Compound specific values & petroleum hydrocarbon ranges found in Table C “GW Cleanup Levels” in 18 AAC 75 & the Surface Water Quality Criteria, which can be found in 18 AAC 70 which supercedes this guidance.
The table incorrectly reflects the current Water Quality Criteria Standards found in 18 AAC 70 which have been amended as of May 27, 1999. Please correct the text in the table.
4.4 GW Sampling Page 4-5
DEC requests clarification on how screening for TPH will determine the presence of chlorinated solvents, which are present in the GW as well. The main purpose of this investigation is to determine the extent of chlorinated hydrocarbons in environmental media at the site (see section 1.5 narrative). DEC requests that adequate screening & laboratory analysis be conducted prior to determining if a boring is “clean” from both chlorinated solvent & petroleum contamination & subsequently used as a sentinel well.
4.7 Background Sampling 4-6
Ordinarily, DEC does not recognize ambient or background GRO, DRO, RRO, volatile halogenated compounds or PAH as naturally occurring. Most organic compounds are not naturally occurring, & defining ambient concentrations is generally reserved for metals such as arsenic, manganese, & zinc.
5.5 Human Health & Environmental Risk Screening & Evaluation Page 5-5
The correct reference for the Risk Assessment Procedures Manual effective date is November 24, 1998 not 1996.
8.0 References Page 8-1
18 AAC 75 has been amended 1 October 1999. Strike the reference to ADEC Interim Guidance Document for Surface & GW Cleanup Levels September 1990 since it has been superseded by 18 AAC 75 & 18 AAC 70 regulations.
A3.7 GW & Product Level Measurements Page A3-24
DEC requests that the Air Force include testing for chlorinated hydrocarbons using an appropriate probe (or other appropriate device) if the hydrocarbon interface probe can only detect petroleum hydrocarbons in GW.
A3.8 Water Sampling Page A3-25
DEC requests the Air Force analyze the samples for chlorinated solvents as well using an appropriate test kit for screening samples since the investigation is focused on chlorinated solvent contamination.
|
Louis Howard |
| 7/11/2000 |
Update or Other Action |
Staff commented on conceptual site model and risk assessment work plan for site. Staff clarified where EPA and ADEC differ on the preliminary risk based benchmarks, to use the most stringent criteria during the risk screening process. |
Louis Howard |
| 7/14/2000 |
Document, Report, or Work plan Review - other |
EPA (Kevin Oates) comments on the Draft DP98 CSM and Risk Assessment WP.
General Comment. The risk assessment methodologies presented are consistent with EPA guidance. The human health and ecological conceptual site models present reasonable exposure pathways and potential receptors. To assist in the development of the ecological risk assessment, a copy of the most recent EPA publication on ecological risk assessment is enclosed. That document is titled: Issuance of Final Guidance: Ecological Risk Assessment and Risk Management Principles for Superfund Sites. OSWER Directive 9285. 7-28P. October 7, 1999.
3-2 3.0 (Last Paragraph) It should be noted in the text that preliminary screening values are typically based on a hazard quotient of 0.1 for non-carcinogens and cancer risk of 1 X 10E-7 for carcinogens.
3-5 3.0 The text at the bottom of page 3-5 discusses the fact that EPA has proposed certain changes to cancer risk assessment guidelines, and that any future changes will be incorporated into the risk assessment for DP-98. Proposed and final changes to risk assessment guidelines can be found at the following website.
http://www.epa.gov/superfund/programs/risk/index.htm
Enclosed for your information is a copy of a recent EPA Region X Supplemental Guidance Assessing Childhood Exposures For Non-Carcinogens. This is for informational purposes only, since a child-only exposure pathway is unlikely for DP-98.
|
Louis Howard |
| 8/1/2000 |
Conceptual Site Model Submitted |
Received final version of the Conceptual Site Model (CSM) and human health and ecological Risk
Assessment Workplan for Site DP-98 at Elmendorf Air Force Base (AFB), Alaska, as part of the
Environmental Restoration Program (ERP) investigation that is being performed in support of an
Engineering Evaluation/Cost Analysis (EE/CA) for the site. The overall program goal is to delineate the nature and extent of contamination at this site and determine the remedial alternative that will best address any site contamination present, if necessary. Subsequently, the purpose of this CSM and Risk Assessment Workplan is to begin to evaluate the potential for human and ecological risk from contamination present at the site and determine if remedial
measures are needed.
|
Louis Howard |
| 8/1/2000 |
Update or Other Action |
Site Characterization Investigation at DP-98 final work plan received. The field investigation objectives are as follows:
* Delineate nature and extent of soil contamination;
* Delineate nature and extent of groundwater contamination;
* Delineate the extent of surface water and sediment contamination in the wetlands, field, and
drainage channels downgradient of the site;
* Establish levels of natural attenuation parameters in soil;
* Establish levels of natural attenuation parameters in groundwater;
* Conduct a risk-based human-health and environment screening evaluation; and
* Determine the source of the contamination.
Results of the 2000 field investigation will be summarized in an EE/CA. The report will present
the following:
* The Site Characterization section will include subsections on site description and background;
source, nature, and extent of contamination; data; and a risk evaluration. This section is similar to a streamlined remedial investigation.
* The Removal Action Objective section will include subsections on statutory limits, removal
action scope, removal action schedule, and planned remedial activities. This section and the
subsequent two sections are similar to a streamlined feasibility study.
* The Identification and Analysis of Removal Action Alternatives section will include a
description of each removal action alternative and discussions of effectiveness, implementability,and cost of each alternative.
* The Comparative Analysis of Removal Action Alternatives section will compare the alternatives
to each other, again with respect to effectiveness, implementability, and cost.
* The Recommended Removal Action Alternative section will use the comparison to show which
alternative is most suitable to the site and will provide rationale for selection of that alternative.This section serves the same purpose as a proposed plan. |
Louis Howard |
| 9/1/2000 |
Update or Other Action |
RCRA Release Assessment and Corrective Action Technical Memorandum Site 29-Elephant Cage Site AFCEE Contract No. F41624-95-D-8004 Delivery order 0056 FXSB007601. Site 29 - Elephant Cage Site is located at the 381 st IS on Fairchild Avenue.
Approximately 15 drums and containers were identified scattered in the woods north of the Elephant Cage access road extending west from Fairchild Avenue and east of the sewage lagoon access road.
Drum BSI0029-14DR was an empty 55-gallon closed top drum labeled Fort Richardson Dry Cleaning Solvent "SD" and was located an estimated 15 feet east of BSI0029-12DR and BSI0029-13DR.
Soil headspace screening samples were collected beneath drums and containers and placed in Ziplock bags. The soils were allowed to warm for a minimum of 15 minutes under the heater in the field vehicle. Soils were field screened with a PID. Results with the PID ranged from 0.0 to 0.3 ppm. No soil samples were collected for laboratory analysis.
The field investigation at Site 29 - Elephant Cage Site indicates that no contamination of the soil is present. Headspace screening samples collected from beneath the drums were below 10 ppm, and no visual evidence of contamination was observed. Based on the results of this investigation, no further action is recommended at Site 29 - Elephant Cage Site.
Appendix B analytical data shows contamination present: DRO 1,290,000 mg/kg, RRO 6,120 mg/kg, GRO 975 mg/kg from sample BSI0028000101SH soil/solid. Sample remarks: DRO/RRO - Surrogate recovers outside controls due to matrix interference. DRO - Pattern consistent with weathered middle distillate. GRO/BTEX - Surrogate recovery is biased high due to matrix interference. Results not affected. (CT&E Environmental Services, Inc. Client Name-Foothill Engineering).
|
Louis Howard |
| 10/2/2000 |
Update or Other Action |
Quarterly progress report received for the 3rd quarter: 1, July 2000-30 September 2000. Interpreted the preliminary results from the Gore sorber screening task along with the common ion data for the groundwater. Accomplished additional Gore sorber screening in July 2000. Finalized TCE investigation work plan, conceptual site model and risk assessment work plan. Discussed and finalized field approach after meeting with U.S. EPA, U.S. AF, contractor and ADEC staff. Started the drilling program in August 2000 and received laboratory results from all the sampling in September 2000. |
Louis Howard |
| 1/12/2001 |
Update or Other Action |
Quarterly progress report received for October 2000 to December 2000. Engineering evaluation/cost analysis (EE/CA) report due to ADEC April 18, 2001. Fieldwork has been conducted with 23 drums of soil cuttings disposed of in December 2000. DP98 analytical data advancement package prepared and a draft risk assessment. |
Louis Howard |
| 1/22/2001 |
Document, Report, or Work plan Review - other |
Curtis Conner (ADEC) sent letter to John Mahaffey (USAF) RE: ADEC Review of SERA Phase VIII ST423/6/7/8 Draft Release Investigation Report, February, 2000
The reports summarizes on-going GW monitoring activities from petroleum hydrocarbon contamination largely originating from a former regulated 3,000 gallon UST that was closed & removed from the ground in August 1995. The tank was replaced with a new 4,000 gallon UST at the same time. Samples collected from the base of the UST excavation contained a maximum detected DRO level of 9,700 mg/Kg.
The report suggests that the contamination at the site may have preferentially migrated ‘drain tile’/utility corridor & the associated bedding material. One of the groundwater monitoring wells, 41-755-WL01, located near the location of the former UST had reported concentrations of 1,300 ppm of DRO, 44 ppm GRO & 0.160 ppm benzene in the GW & the presence of free-phase product. A reported level 160 ppm DRO, 1.3 ppm GRO & 0.007 ppm benzene were identified in GW well 41-755WL02, located about 140 feet down gradient of the former UST & well 41-755-WL01. well 41-755-WL02 is also in close proximity to a ‘drain tile’/utility corridor. This ‘drain tile’/utility corridor system appears to have contributed to migration of soil & GW contamination at the site. Well 41-755-WL05 has a reported level of 18 ppm DRO in the sample collected from this round of sampling & is located approximately 380’ down gradient from the former UST.
Free phase product recovery was abandoned since SERA IV & has not been re-initiated. Recovery of free-phase product is required by current regulations. As a result of this & lack of decisive corrective action, concentrations of petroleum hydrocarbons in the groundwater are above the most liberal cleanup levels & the hydrocarbon contamination plume extends several hundred feet past its original source. The plume appears to be naturally expanding as opposed to naturally attenuating.
Additionally, cis-1,2-Dichloroethene was identified in GW wells 41-755-WL02/03/04/05, at 4.2, 2.1, 2.2 & 5.7 ppm, respectively. A water sample collected from GW well 41-755-WL02 also had a reported concentration 2.8 ppm tetrachloroethene, & in wells 41-755-WL02/04 reported concentrations of 2.3 & 5 ppm trichloroethene, respectively.
All of the above reported levels exceed the GW cleanup levels listed on Table C, 18 AAC 75, & most also exceed the ‘ten times’ rule for cleanup levels. The state cleanup level for DRO, GRO & benzene in water is 1.5, 1.3 & 0.005 ppm, respectively.
The source of the chlorinated solvents (Dense nonaqueous phase liquids/DNAPLs) identified in analytical testing program is not known. The report identifies areas of buried waste. This may or may not be the source of the solvent contamination that is present. Further evaluation of the site will have to be conducted in order to determine the source of these compounds.
A review of the graphical representations of the GW wells at the site indicate that the majority of the wells have the top of their screen sections below static GW conditions. Free-phase product would be difficult to identify from this construction configuration.
The report also concludes that a sand layer with potentially higher rates of hydraulic conductivity underlay a soil type of lower permeability where static GW conditions exist. This distinct water-bearing unit may represent a pathway for contaminant migration from unknown, off-site sources. A soil sample retrieved from the layer contained elevated levels of DRO. This layer is sufficiently below static water table conditions that it is not likely to have been impacted from releases of the former UST system. One soil sample collected at a depth of 28’ bgs in this sand layer in 1996 has a reported level of 37,100 ppm. Another sample collected at a depth of 26.5 feet bgs in 1998 had a reported DRO level of 12,700 ppm. Both of DRO levels in the GW are far in excess of the levels identified at the base of the former UST excavation.
See file for additional information.
|
Curtis Conner |
| 3/22/2001 |
Meeting or Teleconference Held |
Meeting with AF and EPA staff to discuss EE/CA results from 2000 investigation. The purpose for the field investigation was to determine the nature and extent of fuel and chlorinated solvents in soils, surface water, sediment, and the shallow unconfined aquifer; to perform a human health and ecological risk assessment; and to select a remedial alternative that would be protective of human health and the environment. Two primary sources of contamination were identified in the 2001 EE/CA: a drainage tile network associated with Building 18224 and two former USTs that stored fuel for generators located in the garage.
The drainage tile network was identified as the main contributor of chlorinated solvents and a small amount of fuels. The USTs accounted for the majority of the fuel contamination at the DP98 site. In addition, a grease/oil pit that overflowed into the tile drain network was also identified as a possible source of fuel contamination. The vertical and aerial extent of fuel was quantitatively defined northwest of Building 18244 in the vicinity of well 41755-WL07. The vertical and aerial extent of chlorinated solvent contaminated soil was quantitatively defined at DP98 site. The EE/CA did not fully delineate the nature and extent of surface (sediment) contamination.
The extent of the groundwater plume was defined in all directions except to the northwest. In this direction, the boundaries for DRO, GRO, benzene, BTEX plumes were only qualitatively defined. TCE, PCE, DCE, VC solvent plumes extended in a north-northwesterly direction, following the prevailing groundwater flow from the historic drainage tiles near building 18224. The TCE plume extended north from the northwest drainage tile slightly past the base of the slope.
Summary of groundwater results warrant finishing up EE/CA work and begin RI/FS process under CERCLA. Chlorinated solvent contamination is extensive in the shallow aquifer. Maximum concentrations from the shallow aquifer are as follows: cis 1,2-dichloroethene at 3,899 ug/L, 1,1-dichloroethene at 12.11 ug/L, tetrachloroethene at 2,989 ug/L, trichloroethene at 3,815 ug/L and a first ever showing of vinyl chloride at 12.26 ug/L. |
Louis Howard |
| 4/6/2001 |
Document, Report, or Work plan Review - other |
EPA (Kevin Oates) comments on the EE/CA for DP98
I agree with the assessment that due to the expanding nature and extent of contamination that has been detected through efforts to date at DP-98, it is more appropriate for the USAF to proceed with future activities as a CERCLA remedial investigation and feasibility study (RI/FS) that will lead to selection of a remedial action(s) in a record of decision. The current efforts have been through removal authorities due to what was believed to be a limited problem. This is no longer the situation and recently reported site conditions warrant an expanded investigation.
I agree with the recommendations presented under section 13.7 for addition work at DP-98. I would also recommend the following activities for additional investigation and evaluation.
• Better delineate the nature and extent of potential contamination with respect to the regional lower aquifer. It is important to understand if the potential exists (or has already occurred) for contaminant migration to this formation since it is a source of potable water.
• Performance of a human health and ecological risk assessment to determine potential exposure pathways and adverse risks, as well as to evaluate potential risk reduction for remedial alternatives.
• Sampling for natural attenuation parameters (dissolved oxygen, reduction/oxidation potential, presence of dissolved methane, ferrous iron, etc.) to determine natural attenuation rates. Please see the EPA publication Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites. OSWER Directive 9200.4-17 for a more complete discussion of appropriate constituents for sampling.
• Evaluation of additional attenuation biodegradation approaches for soils and groundwater beyond the two propriety methods listed in the document. The potential for transformation to more toxic by-products (e.g. TCE to vinyl chloride) has not been given sufficient consideration. It may be appropriate to evaluate several methods through bench scale or pilot scale studies to determine a range of cost effective options.
Relevant documents for your consideration during transition to an RI/FS approach include the following:
• Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA. EPA/540/G-89/004. 1998.
• Risk Assessment Guidance for Superfund. EPA/540/1-89/002. December 1989.
• A Guide to Preparing Superfund Proposed Plans, Records of Decision, and Other Remedy Decision Documents. EPA 540-R-98-031. July 1999.
These and many other Superfund related documents can found at the following EPA websites and downloaded at no charge.
http://www.epa.gov/superfund/pubs.htm
http://www.epa.gov/superfund/programs/risk/tooltrad.htm
I have enclosed an index list of available publications at those two sites for your convenience. Copies of all of these documents can also be ordered from NTIS, which does charge for reproduction and shipping. NTIS can be reached at 1-800-553-6847.
Recommend that the USAF, EPA, and ADEC discuss re-scoping efforts once final comments have been provided to the USAF to facilitate a smooth transition from the removal approach to the remedial approach for site characterization and remediation. The remedial methods typically place a greater emphasis on the development of data quality objectives and compliance with applicable or relevant and appropriate requirements. |
Louis Howard |
| 4/30/2001 |
Document, Report, or Work plan Review - other |
Staff reviewed and commented on a draft engineering evaluation/cost analysis for the site. ADEC concurs with the recommendations to move the investigation into a CERCLA remedial investigation and feasibility study (RI/FS). This is due mainly to the extensive chlorinated solvent contamination uncovered by the engineering evaluation/cost analysis (EE/CA) investigation, which is a much bigger problem than previously suspected.
ADEC disagrees with the statement that these regulations are not considered an applicable or relevant and appropriate requirement (ARAR). ADEC requests the text be corrected to include 18 AAC 78 as an ARAR. The text states that 18 AAC 80 State of Alaska Drinking Water Regulations, dated 23, August 2000 will not be considered an ARAR due to the fact that current and future use is not likely for the purposes of drinking water.
ADEC disagrees and is not aware that Elmendorf has gone through the necessary steps for reclassifying the groundwater as non-potable. Numerous record of decisions have been signed by EPA, ADEC and the Air Force stating the shallow aquifer would be cleaned up to meet drinking water MCLs (OU 1, 2, 4, 5, 6). ADEC requests 18 AAC 80 be included in the list of ARARs.
ADEC agrees with the recommendations in this section for additional work at DP-98. ADEC requests the RI/FS work investigate the nature and extent of the possibility of contamination of the deep (lower) aquifer from chlorinated solvents. ADEC does not concur that there is no need to do a risk assessment for human health or ecological receptors as alluded to in section 13.6. ADEC expects the Air Force will conduct a baseline human health risk assessment and ecological risk assessment as a part of the RI/FS process for this source area.
ADEC requests the Air Force sample for natural attenuation parameters at this source area. For example: chloride, iron (II), hydrogen, manganese, methane, ethane, and ethene, and oxidation-reduction potential. It is recommended that the three agencies project managers meet to discuss scoping efforts and begin the process of incorporating this source area into the Federal Facility Agreement. |
Louis Howard |
| 6/6/2001 |
Document, Report, or Work plan Review - other |
USAF Response to Comments on the EE/CA for DP98
1) Noted. Continued investigation at this site under CERCLA guidance is currently under consideration by the Air Force.
2) Noted. Concur. An effort to determine the nature and extent of contamination of the lower aquifer may be included as part of a follow-on investigation.
Partially Concur. A human-health and ecological risk assessment was performed for the EE/CA. If a revised risk assessment is deemed necessary, this may be completed under a follow-on investigation.
Concur. Additional sampling of natural attenuation parameters as part of additional groundwater sampling rounds is currently under consideration by the Air Force.
The most applicable remediation methods were evaluated for the EE/CA. The potential human-health and ecological risk of vinyl chloride to receptors is considered low due to the relative instability of the compound in aerobic environments, where exposure would most likely occur. An expanded assessment of this impact and any remedial options may be evaluated in a follow on investigation.
3) Noted. The latest version of the Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA is 1988 according to the web sites referenced.
4) Concur. A meeting between the Air Force, ADEC, and EPA to discuss data gaps is presently planned for 10 July 01.
Response to Joe Williamson Comments
1) Concur. This figure will be added to the EE/CA report.
2) Concur. This figure will be added to the EE/CA report.
3) Gore-sorber™ screening results are measured in micrograms of analyte per gram of sorbent (i.e., ug/g) Report figures will be standardized to ?g/g.
4) While not technically a “perched aquifer,” there is a discontinuous interval of moderately permeable, saturated soil zones within very tight fine-grained sediments between approximately 15 to 30 feet below ground surface. The vertical limits of saturated soil in this area, was not confirmed during the 2000 field investigation. The interconnections between these saturated zones are not clear as the 2000 soil borings did not extend deep enough to identify confining units. These issues remain data gaps to be addressed during a follow on investigation. An additional subsurface investigation may need to be completed before product recovery efforts can begin. |
Louis Howard |
| 7/12/2001 |
Meeting or Teleconference Held |
EE/CA TCE at DP98 Meeting minutes at URS. Mr. Mayer opened the meeting by emphasizing that the purpose was to discuss USEPA, ADEC, and Air Force review comments for the draft Engineering Evaluation/Cost Estimate (EE/CA) that was submitted in early February 2001 prior to finalizing the document, and to discuss potential future investigation and sampling efforts. Mr. Mayer informed the attendees that prior to this meeting he had discussed the draft EE/CA with URS, USEPA, and ADEC. All agreed that, based on the EE/CA findings, a follow-on Remedial Investigation/ Feasibility Study (RI/FS) was necessary at Site DP-98. Mr. Mayer also stated that
he believed that the RI/FS effort would be streamlined by using the EE/CA as a base, then addressing the data gaps within the RI/FS.
Mr. Mayer discussed the following general comments with URS prior to this meeting:
He recommended that the recommendations for the EE/CA report should include a follow-on
RI/FS effort to address the data gaps. This should be accomplished in the Recommendation
section of the report in 25 words or less. Revise any Rl/FS references to EE/CA references (e.g., use "removal action" instead of "remedial action").
Mr. Oates and Mr. Howard each expressed their concern about the potential for contamination at Site DP-98 to migrate vertically and impact the lower aquifer. This issue will be addressed during the follow-on investigation. Mr. Oates recommended a minimum of three monitoring wells (one upgradient and two downgradient) would be necessary to characterize the lower aquifer and to determine the regional groundwater flow direction. For estimation purposes, up to five wells may be necessary at Site DP-98 to investigate the lower aquifer.
Mr. Denver recommended that deep wells not be installed within areas with known contaminated
groundwater because this would elevate the potential for vertical migration to the lower aquifer. Instead, wells located upgradient and downgradient of the site would be sufficient to determine if Site DP-98 had impacted the deeper aquifer. Mr. Oates and Mr. Howard agreed with Mr. Denver that no wells will be necessary within source area at Site DP-98.
Mr. Williamson suggested that several monitoring wells currently exist that can contribute to the understanding of the regional groundwater aquifer beneath the Elmendorf Moraine. These wells are located within Sites SD15, OU6, and SD41. However, these wells may not be close enough to Site DP-98 to provide relevant information.
While discussing the comments concerning the Risk Assessment (RA), Mr. Denver distributed photocopies of a limited RA for chlorinated compounds in groundwater that was prepared for the SERA VI investigation in 1997. This limited RA used four downgradient monitoring wells (41755-WL06, WL07, WL08, and WL09), each located at the base of the slope. USEPA and ADEC comments included a recommendation for assessment of contamination to receptors via groundwater. Mr. Denver inquired if the RA should be recalculated using the groundwater data from the 2000 EE/CA investigation or, the RA should be revised using analytical data from an upcoming groundwater sampling round in the next few months. Mr. Mayer recommended that he would like to revise the RA for groundwater after additonal data is available (i.e., after the RI/FS investigaton) since a revised RA will be necessary for RI/FS.
Mr. Oates stated that, based on preliminary discussions with the Air Force concerning the investigative findings, the USEPA reviewed the data in the EE/CA report as a platform for the RI/FS. Thus, he did not place significant time and effort into reviewing the RA or FS portions of the report. Mr. Howard concurred with this statement.
Mr. Oates and Mr. Howard agree that an uncertainty analysis based on trend analysis could be used to assess the relative risk associated with groundwater at Site DP-98.
While discussing the wetlands issues downgradient from Site DP-98, Mr. Oates stated that wetland permits are not mandated for CERCLA investigations.
Mr. Mayer stated that the remedial alternatives outlined in the EE/CA need to be expanded and revised to provide a more accurate comparison of these alternatives. Particular attention should be paid to:
> Determining actual costs/operations & maintenance of alternatives;
> Evaluating alternatives listed in the AFCEE's Technology Transfer; and
> Evaluating other alternatives (e.g., chemistry transfer that will react with contaminants to make them benign.)
See file for additional information. |
Louis Howard |
| 10/8/2001 |
Update or Other Action |
Maximum contaminant levels above cleanup levels were detected in the following wells in October 2001: Well 41755-WL02 had PCE at 6,400 ug/L, TCE 4,400 ug/L, 1,1-DCE at less than 24 ug/L and vinyl chloride at less than 43 ug/L. Well 41755-WL04 had cis-1,2-DCE at 4,700 ug/L. |
Louis Howard |
| 4/3/2002 |
Meeting or Teleconference Held |
Meeting minutes for RPMs: DP98-RI/FS project awarded on March 2002, Milestones will be added to the FFA this month if possible. Recommend meeting every month to do an update on the RI/FS project. |
Louis Howard |
| 4/17/2002 |
Update or Other Action |
DP98 Remedial Investigation/Feasibility Study (RI/FS) at Elmendorf AFB, AK. Scoping Meeting with Agencies Discussion Topics submitted by the Air Force before the 4/18/2002 meeting.
FIELDWORK
1. A great deal of site-specific information for DP98 was collected during the EE/CA in 2000. The current investigation deals with addressing only data gaps as identified using data from the EE/CA.
2. Deep wells will be installed at the DP98 area to characterize the lower aquifer. These wells will probably be installed south, northeast, and northwest of Building 18224; these locations are believed to be uncontaminated.
3. Deep soil borings (3 soil samples/boring) may be drilled to determine the vertical extent of fuel and solvent contamination near Building 18224. These borings will use conductor casing to prevent the vertical migration of contaminated water down the borehole.
4. Soil borings may be drilled to determine the downgradient extent of fuel and solvent contamination; some of these soil borings may be converted to monitoring wells, if necessary.
5. Groundwater grab samples may be collected from well points installed just upgradient of the base of the slope downgradient of Building 18224. Although well points are typically considered to provide screening level information, the installation of these points should be considered laboratory grade data.
6. Six sediment and surface water samples may be collected near the base of the slope.
Analytical
1. Groundwater samples collected from 18 existing wells (41755-WL01 through –WL10, and –WL12 through –WL19) in October 2001 were analyzed for PCBs and pesticides in October 2001. No PCBs were detected above method detection limits. Endosulfan sulfate (1 sample) and gamma BHC (2 samples) were detected above method detection limits, but below method reporting limits (i.e., “F-flagged results”). Based on the absence of these compounds in the groundwater at DP-98, these compounds are not considered contaminants of concern and will not be included in the RI/FS analytical suite.
2. Groundwater samples collected for the EE/CA (October 2000) did not detect metals above background or 95% UCLs calculated for the OU6 RI. Therefore, additional analyses for metals in groundwater are not considered necessary for the existing wells; however, these analytes will be included in the analytical suite for the new wells.
3. There are currently 3 rounds of groundwater samples for chlorinated solvents and fuels (1999, 2000, and 2001). With the additional round of groundwater data this summer (2002), these four rounds should be sufficient to establish trends for contaminant migration, plume movement, and natural attenuation. Also, the 2001 and 2002 meet the recommendation for additional work included in Section 13 of the final EE/CA.
4. With the collection of six additional surface water and sediment samples, there will be 10 samples in the data set. Together these complete data set should allow a 95% UCL to be calculated for these media at DP98.
5. Additional background samples for all media will not be collected under the DP98 RI/FS. All new data will be compared to background values calculated for the OU6 RI and/or the EE/CA.
Planning
1. Several documents have been prepared for the EE/CA that could serve as planning documents for the RI/FS. With minor revisions and/or an addendum outlining new tasks/work that will be conducted this summer, these documents could be used as the planning documents (e.g., workplan, CSM/risk assessment workplan) for the RI/FS.
Risk Assessment
1. The risk assessment workplan developed for the EE/CA will be revised and resubmitted for the DP98 RI/FS.
2. Human-health and ecological risk assessments were prepared for EE/CA. Using additional analytical data for the RI/FS, these assessments will be revised. Also, the human health risk assessment will be re-run to evaluate risk considering the shallow aquifer at DP98 as a potential drinking water source.
3. Based on the SERA and EE/CA analytical results, the following COCs have been determined for DP98:
Soil DRO, RRO, TCE, cis 1,2-DCE, PCE.
Sediments DRO, RRO (Chloroform and methylene chloride also found but considered lab contaminants.
Surface Water DRO, RRO
Groundwater GRO, DRO, TCE, PCE, benzene, cis 1,2-DCE, 1,1-DCE, and VC.
4. Groundwater samples collected at well 41755-WL05, located at the top of the slope, in October 2001 detected 16 ?g/L of vinyl chloride. This well is the only well at DP98 where vinyl chloride is consistently detected in the groundwater. Well points will be installed at the base of the slope to intercept groundwater just before it seeps out of the slope to determine if this compound could potential impact environmental receptors.
|
Louis Howard |
| 4/18/2002 |
Meeting or Teleconference Held |
DP98 RI/FS scoping meeting with agencies. The purpose of this confirmation notice is to document the significant decisions reached and pertinent issues discussed during this project meeting. The purpose of the meeting was to: a) re-introduce the DP98 RI/FS program to representatives of the United States Environmental Protection Agency (USEPA) and Alaska Department of Environmental Conservation (ADEC), b) present a workable project schedule for
fieldwork and deliverables, and c) work through a list of discussion topics that were previously sent to all parties.
The USAF has targeted funds to conduct remedial design/remedial action (RD/RA) at DP98 in FY04. To accomplish this project award, the Record of Decision (ROD) for DP98 must be signed before
1 November 2003; otherwise this funding may not be available for use on this site.
The following field tasks were discussed:
a) At least three deep wells will be installed at the DP98 area to characterize the lower aquifer.
b) Additional deep soil borings are planned to determine the vertical extent of contamination beneath the DP98 facility. The Agencies are not sure this additional data would be necessary.
c) Additional soil borings are planned to determine the downgradient extent of fuel and solvent
contamination; two of these soil borings may be converted to monitoring wells if necessary.
d) Groundwater samples collected from well points installed at the base of the slope to intercept groundwater just before it seeps out of the slope to determine if this compound could potential impact environmental receptors. The purpose of these groundwater samples is to determine whether chlorinated solvents are a risk to environmental receptors downslope of wells 41755-WL05 and -WL08. These wells contained high concentrations of vinyl chloride, cis 1,2-DCE,
and TCE in past sample rounds.
e) Sediment and surface water samples are planned to be collected from areas at the base of the slope and within the wetland.
f) One additional round of groundwater sampling is planned for all wells after the field effort. The purpose of this round is to establish trends for contaminant migration, plume movement, and natural attenuation.
Human-health and ecological risk assessments were prepared for EE/CA. Using additional analytical data for the RI/FS, these assessments will be revised. Also, the human health risk assessment will be re-run to evaluate risk considering the shallow aquifer at DP98 as a potential drinking water source.
8. MODFLOW, BIOPLUME 3, or another "off-the-shelf' software package should be used to model the
hydrogeologic conditions at DP98.
9. ADEC (Stephanie Pingree, risk assessment - Juneau) has had URS use an ADEC carcinogenic value
of 10-6 and HQ = 0.1 for non-carcinogenic risk for preliminary screening, but EPA uses values of 10-7 and HQ = 0.1. EPA's values were used for the EE/CA. Mr. Oates wanted the preliminary screening to use 10-7 so as to only to show "what could be a problem." After this determination, ADEC's carcinogenic value of 10-6 and HQ = 0.1 for non-carcinogenic risk would be acceptable. URS will review the PCOC list to determine if there are any compounds that would drop out at 10-6 that are included at 10-7
The wetlands at the base of the slope downgradient of DP98 may be impacted by seepage of
contaminated groundwater near wells 41755-WL07, -08, and -09. Surface soil and sediment samples
will be collected at the base of slope to determine the extent of any contamination; the data for these samples will be evaluated in the ecological risk
URS will look into using the wetland downgradient of DP98 as a bioremediation area.
Mr. Oates believes that several in situ remedial alternatives could be used at DP98. Also, separating contaminated media into operable units or stratigraphic areas could also be considered.
There is strong evidence for natural attenuation based on preliminary screening worksheet calculations using both 2000 and 2001 groundwater data. These worksheets were distributed to all attendees of this meeting in order to show how well natural attenuation is currently working at DP98.
Free product has been measured in three wells near Building 18224. The limits of the free product have been defined and appear to be stable due to the impervious asphalt cover at the facility, which restricts infiltration that would typically mobilize the free product. Although ADEC guidance typically requires immediate recovery of free product from groundwater, URS requested that the Agencies postpone this effort to allow the product to stimulate natural attenuation of the chlorinated solvent in groundwater. |
Louis Howard |
| 5/3/2002 |
Update or Other Action |
Staff reviewed and commented on the scoping document for field work at DP98. Staff requested monitoring wells at DP98 be added to the Base wide groundwater-monitoring program and additional contaminants of concern be included for monitoring/sampling at the site: soil: tetrachloroethene (PCE) and 1,1-DCE, surface water: Cis-1,2-DCE, groundwater: PCE.
Increasing TCE and PCE concentrations in groundwater are not indicative of natural attenuation. Nor are the increasing concentrations of PCE in groundwater noted in "Other Issues" at Item 2 indicative of natural attenuation.
Recovery of free product is not optional guidance the Air Force may or may not choose to implement. See Sec. 46.03.740. Oil pollution, Sec. 46.04.020. Removal of oil discharges, 18 AAC 75.325(f) and because there are leaking underground storage tanks at the site see also: 18 AAC 78.240 Corrective action (b).
The Department recognizes that in some cases it may not be technically practicable to implement an active or passive recovery system for free product. The Elmendorf Remedial Action Report for Operable Unit (OU) 2 (September 1998) set a precedent for defining what is meant by “technically practicable” for free product recovery. Section 2.4.1 Product Recovery Endpoints at the 1st bullet on page 10 states: “As designed and constructed, the ST41 ground water treatment system cannot recover floating product when there is less than a measurable thickness of 0.1 feet of product. Therefore, as an endpoint for product recovery, if less than 0.1 feet is sustained for one year, recovery at that source can be discontinued. Floating product will be measured monthly. When product thickness falls below 0.1 feet for one year, the recovery of product at that source will not be considered “technically practicable.”
Where free product is greater than 0.10 feet, the Department expects a corrective action (active or passive) to be implemented for free product recovery at DP98. The 2001 EE/CA report states that during the 2000 field work, floating product was detected in wells: 41755-WL01, 41755-WL03, and 41755-WL11. A passive product recovery system was installed in 4755-WL01 and operated between April and December of 1996. Choosing to not implement a recovery system is not acceptable to the Department. Please indicate in your written response to this letter, what corrective action that the Air Force intends to take to address free product at the site. |
Louis Howard |
| 7/1/2002 |
Document, Report, or Work plan Review - other |
EPA (Kevin Oates) comments on the Addendum to Site Characterization Investigation at DP-98, Final Work Plan. 26 June 2002 Elmendorf Air Force Base AK.
The U.S. Environmental Protection Agency (EPA) has completed it s review of the above referenced documents. EPA’s comments are presented below.
The Work Plan as written is approved by EPA. As a point of clarification, the Project Managers for the U.S. Air Force, EPA, and the State of Alaska, Department of Environmental Conservation have not yet agreed to the milestones described in Chapter 7 and shown on Figure 10. For planning purposes for the execution of the 2002 field season, the milestones, documents, and associated activities listed in the work plan are adequate. However, the Project Managers still do need to agree on primary and secondary milestones, and amend the Elmendorf Federal Facilities Agreement to reflect such an agreement. The information presented in this Work plan should form a good basis to pursue those discussions in earnest. |
Louis Howard |
| 7/3/2002 |
Site Characterization Workplan Approved |
Staff reviewed and commented on the addendum to the site characterization investigation at DP98. Document was approved as submitted.
However, the project managers for the Air Force, Environmental Protection Agency (EPA) and the State will have to discuss and agree in writing to the milestones discussed in Sections 7.0 and 10.0 (as shown on Figure 10). The September 19, 1991 Federal Facility Agreement (FFA) for Elmendorf Air Force Base will require modification to include source area DP98. An initial review of the FFA shows that Section XXXIII Modification/Amendment of Agreement on page 60 is an appropriate section to review and begin a dialogue between the agencies.
Please note the Department’s review and concurrence on the document is to ensure that the work is done in accordance with State of Alaska environmental conservation laws and regulations. While the Department may comment on other state and federal laws and regulations, our concurrence does not relieve the U.S. Air Force or its consultants, contractors, or civilian personnel from the need to comply with other applicable laws and regulations. |
Louis Howard |
| 8/2/2002 |
Update or Other Action |
Addendum to Site Characterization Investigation at DP98 Final Work Plan received. This document is an addendum to the Site CharacterizationI nvestigation at DP98, ElmendorfAir
Force Base, Final Workplan (United States Air Force [USAF], 2000c), hereafter referred to as the "2000 Workplan", which outlines proposed field activities necessary to conduct a remedial investigation/feasibility study (RI/FS) as required by USAF Contract F41624-00-D-8028, Task Order 0072 (TO 0072). Site location and site layout are shown on Figures 1-1 and 1-2. The 2000 Workplan and this addendum together serve as the management plan for the DP98 RI/FS. Amendments to the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP) of the 2000 Workplan are included as Attachments A and B, respectively, of this addendum. Comments from the Alaska Department of Environmental Conservation (ADEC) and the United States Environmental Protection Agency (USEPA) to the draft version of this addendum (dated 26 June 2002) are included as Attachment C.
The USAF, USEPA, and ADEC reviewed the DP98 EE/CA in April 2002 to define any data gaps that need to be addressed during the RI/FS. Both USEPA and ADEC provided their comments on the
DP98 EE/CA data gaps to the USAF on 3 May 2002. Based on these comments, and considering the
recommendations presented in the DP98 EE/CA, the following tasks are defined:
1. Perform further investigation of the lower aquifer to determine the limits of groundwater
contaminant migration.
3 2. Determine if fuel and/or chlorinated solvents are seeping out of the base of the slope north of Building 18224 in concentrations that could be a risk to receptors.
3. Perform additional surface water and sediment sampling to better delineate the extent of
contamination in the wetlands downgradient of DP98. 3 4. Evaluate the risk to human health receptors if the shallow aquifer is considered a potential drinking water source.
3 5. Perform groundwater modeling to provide plume migration and natural attenuation data for the feasibility study.
As agreed upon by the USAF, USEPA, and ADEC, the Site Characterization Investigation at
DP98 Elmendorf, Alaska, Final Workplan (USAF, 2000c) along with this addendum will satisfy the
requirement for the management plan for the DP98 RI/FS.
Once data gaps identified in the 2001 EE/CA have been addressed, a remedial investigation will
be prepared using the information in the EE/CA with the newly collected data from the field
investigation. The feasibility study prepared for the DP98 EE/CA will be updated and expanded using data collected during the remedial investigation. |
Louis Howard |
| 10/24/2002 |
Update or Other Action |
Correspondence to USAF C. Mayer from ADEC re: Pump Test at Site DP98, purge water treat/discharge onsite. State cleanup levels that must be kept in mind for this activity:
1) The Alaska Water Quality Standards specifically at 18 AAC 70.020(b) for Toxic and Other Deleterious Organic and Inorganic Substances and Petroleum Hydrocarbons, Oils and Grease (where applicable, in non-wetland areas, where no immediate surface waters would be affected by the land discharge and where groundwater is greater than 10 feet below the land surface, the TAH and TAqH numeric will be replaced by a "report" condition (e.g. sheen/no sheen, DRO, GRO & BTEX). Numeric (TAH/TAqH) effluent limitation apply to any discharges to wetlands.); and
2) The discharge must meet cleanup levels under Contaminated sites regulations, specifically 18 AAC 75.345 Groundwater and Surface Water Cleanup levels found in Table C.
3) Finally, any requirments and conditions for Elmendorf's NPDES permit or absent a permit then those substantive requirments under 1 8 AAC 72 Wastewater Disposal.
What is the expected duration of the discharge and average and maximum daily flow rates anticipated? If the ultimate disposal point is the storm water/sewer system then the discharge cannot contribute to or cause to exceed the system's maximum quantity and quality approved in the Air Force's wastewater system plan review.
We cannot speak for the U.S. Environmental Protection Agency's position on the proposed action, the Department concurs with the proposed action as long as the purge water which is is being discharged will be sampled periodically for site DP98's specific COCs, known to exist at this time, to ensure that breakthrough of the GAC unit has not occurred. The discharge is to be sampled and tested for COCs, at a minimum, at startup, midpoint and the end of the test.
Effluent monitoring results, along with the total volume of water treated (gallons) and discharged (gallons per day) to be provided to the Department. This authorization to discharge represents a conditional one time discharge approval specific to this site and this test. Any subsequent discharges will require separate review and authorization.
Sampling and testing to be done in accordance with applicable EPA and State of Alaska approved methods. The Department's review and concurrence on the request to treat the purge water and discharge it to a drainage ditch to ensure the proposed action is in accordance with State of Alaska environmental conservation laws and regulations.
While the Department may comment on other state and federal laws and regulations, our concurrence on the action does not relieve the United States Air Force (USAF) or its consultants, contractors, or AF civilian personnel from the need to comply with other applicable laws and regulations. |
Louis Howard |
| 11/15/2002 |
Update or Other Action |
Staff reviewed and commented on the draft remedial action objectives which included ARARs. |
Louis Howard |
| 12/20/2002 |
Document, Report, or Work plan Review - other |
Kevin Oates (EPA) Comments on the FS alternatives for DP98 emailed to C. Mayer (Air Force).
1. No Action is missing from the list of combinations. It is a CERCLA requirement for baseline conditions to compare & contrast alternatives.
2. The combination of alternatives beyong the No Action are logical, and for that matter the only combinations of soil & GW remedies.
3. The FS should be presented as....1) the possible technologies (already done)....2) the screening step (needs to be re-done based on wednesdays meetings & to get rid of the30 year bench mark),..3) the detailed analysis based on the CERCLA 9 criteria (needs to be re-done for same reasons as # 2). The detailed analysis can include a combination of soil and GW remedies, or it can be a follow on discussion. I would recommend the latter since that will be easier to follow the logic. The combinations then do not have to go through the same level of detailed analysis. However there will need to be some discussion for admin record purposes to explain (even qualitatively) how the combinations are beneficial.
4. On a related topic. The FS report generally does not make a specific recomendation for a prefered alternative. This is one area where a CERCLA FS takes a different route from a NEPA EIS. The idea being that the proposed plan is the vehicle to go to the public and say....we have this FS with a bunch of alternatives that will all work.
Here is the one we like best and here is why. Then ask the public to comment on it. Based on that input the prefered alternative can become the selected alternative, or can be modified, or something else can become the selected alternative. The area to stay clear of is the perception that the decision has already been made. The PP and public comment period are statutory requirements that are tied to due process rights under the Constitution. The legal test for remedy selection is could a "reasonable person" come to the same decision as the agencies based on the Admin Record. This is not the same as...does someone agree or like it, but could they come to the same conclusion. If the process appears biased based on the AR, (such as the FS stating Alternative XYZ is the way to go) then legal challenges can and have prevailed.
The FS needs to do the compare and contrasting of alternatives in a manner that someone reading the document can understand the strengths and limitations of the various alternatives. There can and should be a table and/or text that "rates" the alternatives (numerical scores, low medium high, etc) on their ability to meet each of the first seven critieria numbers 8 & 9 come after public comment period and are documented in the ROD.
5. Cory's last note about comparing alternatives 2 to 6 against MNA is only partially correct. Yes this should be done, but ALL alternatives need to be compared and contrasted to each other in the analysis. As I stated above, combinations are okay to follow the detailed analysis. But even then, the No Action still needs to be in the mix. |
Louis Howard |
| 1/15/2003 |
Meeting or Teleconference Held |
Meeting Minutes EAFB Basewide Monitoring Program. January 14, 2003. Attendees: J Williamson (USAF) G Fink (USAF), J. Klasen (USAF), K. Oates (USEPA), L. Howard (ADEC), C. Hinds (URS), P. Dworian (URS), K. Paul (URS).
Agenda: Discuss ADEC’s request to add the analyses of Diesel Range Organics (DRO) and Gasoline Range Organics (GRO) to several Operable Units at Elmendorf.
Summary of Discussion:
1. URS summarized recent (year 2000) ADEC risk assessment guidance that shows that DRO and GRO themselves can cause noncarcinogenic human health risks. This information was not known during preparation of the risk assessments and RODs for Elmendorf Operable Units. Therefore, addition of DRO/GRO to the sampling scheme for Elmendorf was recommended.
2. The Air Force agreed to add DRO/GRO, but cannot add funding to cover the additional analysis until 2004.
3. The following was decided on implementation:
A. This decision will be documented in the 5-Year Review. The addition of DRO/GRO to the program should be introduced in the 5-Year Review under mention of new issues affecting protectiveness.
B. The Air Force will NOT add DRO/GRO as a CERCLA ARAR, but will compare DRO/GRO results to ADEC cleanup levels in the annual reports and will discuss in subsequent 5-Year Reviews. The benefit of this is that if CERCLA COCs meet ARARs, the Air Force can achieve a partial delisting.
C. The Air Force will add DRO and GRO to the suite of analyses at monitoring wells associated with fuel plumes starting in 2004.
D. The Air Force will not pursue a decision document with ADEC on DRO/GRO until more data is gathered on the extent of the problem.
E. Until a decision document is signed with ADEC, GRO and DRO concentrations will be compared to ADEC regulations in 18 AAC 75 (Table C, Groundwater Cleanup Levels; 1,500 µg/L for DRO, 1,300 µg/L GRO).
F. Sampling frequency for DRO/GRO will follow the latest Decision Guide for Sampling Frequency (see 2002 Basewide Annual Report). “Immediately upgradient” means within a 2-year warning line, similar to that generated for OU5.
G. ADEC GRO/DRO criteria apply to groundwater, not to seeps which daylight as surface water. Criteria in 18 AAC 70 (TAH, TaqH) apply to surface water. |
Louis Howard |
| 3/25/2003 |
Site Characterization Report Approved |
Staff commented on the draft remedial investigation/feasibility study received on March 10, 2003. The remediation goal for 1, 2, 4-trimethylbenzene is listed as 2.0 mg/L. The Department requests further information on where the origin of this cleanup level came from. There are no State cleanup levels in water for this particular contaminant. The EPA Region 3 risk based concentration (RBC) for this contaminant at 12.33 ug/L for tap water. Naphthalene is listed in table ES-2 as having a remediation goal of 1.46 mg/L. 18 AAC 75 lists a groundwater cleanup level of 0.7 mg/L and EPA’s RBC level is 6.51 ug/L for tap water. The Department requests the remediation goal be changed to reflect 0.7 mg/L.
Pending, EPA comments on the document and incorporation of the above changes, the Department will have no further comments on the document. |
Louis Howard |
| 3/25/2003 |
Update or Other Action |
Risk assessment approved as part of the remedial investigation/feasibility study report for DP 98. The results of the risk characterization in the DP98 HHRA indicate that future exposures to contaminants in groundwater could pose an unacceptable threat of cancer and noncancer effects, particularly due to TCE in groundwater. No contaminants were identified as COCs in any media other than groundwater. TCE was identified as a COC in groundwater through the drinking water pathway and was the only contaminant identified as a COC through the inhalation of groundwater vapors in indoor air pathway. However, recent air sampling conducted in Building 18224 identified no significant health risk to personnel based on the building’s current usage. Future neighborhood recreational cancer risks and noncancer hazards were well below target health goals; therefore, no contaminants were identified as COCs in sediment and surface water; and this scenario is not included on the risk/hazard summary tables in this ROD.
For surface soil no contaminant concentrations exceeded their associated RBSCs (i.e., no HQs exceeded 1.0); therefore, no contaminants were identified as COPECs. Almost all of the ecological risk is from a small area adjacent to the wetland, north of Building 18224. Contaminants that led to a hazard quotient greater than 1 were:
2-Methylnaphthalene and Fluorene.
In addition to the RI/FS and risk assessment, the Air Force conducted a pump test to verify that groundwater flow does not exist between the upper and lower aquifer. A continuous draw-down aquifer test and step down test was conducted in well 41755-WL21. Based on the pump test results, it appears that there is some degree of groundwater communication between the clayey gravelly silt and sandy gravel unit and the lower gravelly salty sand unit. However, analytical samples from the lower aquifer were collected from four deep wells and samples did not contain any of the target analytes at concentrations above the screening criteria, indicating that cross contamination has not occurred. |
Louis Howard |
| 4/17/2003 |
Update or Other Action |
US Dept. of Interior, Fish & Wildlife Service, Ecological Services sent a letter to Daniel A. Barnett, Chief, Environmental Flight RE: Draft RI/FS for DP98. Trichloroethylene (TCE): Based on a limited review of the subject document, it is clear that TCE is a contaminant of concern at this site. As we discuss below, there are two TCE-related issues that require additional consideration.
The text indicates that no more than half of either the soil samples (32 of 64; page 6-23, section 6.3.2.1) or groundwater samples (34 of 71; page 6-51, section 6.5.2.1) resulted in detectable
concentrations of TCE. This is inconsistent with tables 6-3 and 6-9, which indicate that TCE was detected in all soil and groundwater samples in which they were analyzed. Excluding these detected samples from discussion does not appear to be adequately justified or explained within the document. Also, it is unclear how excluding these samples might affect the shape or extent of the modeled TCE plume depicted in Figure 6-6.
Given TCE's prominence at the site, it is unclear why it was excluded from ecological risk consideration in tables 9-2, 9-3 and 9-4 and thus, not retained through the remaining ecological
risk discussion.
Contaminants of potential ecological concern (COPECs): The results of the groundwater transport model suggest that site-related contaminants are only just beginning to show up in the
wetland area. If an active remediation strategy is not employed at the site, it is likely that the COPECs and the resultant ecological risks will change over time and may increase. Such a
potential change in risk is not addressed by this document and should be considered.
Several contaminant concentrations currently exceed screening levels. Also risk assessments demonstrate that both human health and ecological risks exist at the site. Groundwater modeling
suggests that these concentrations may increase over time, increasing the risk. We therefore do not believe that Alternative 2 (monitored natural attenuation) alone is a fully adequate remedy, since contamination is left in place and no physical removal or treatment of contamination will occur. If you have any questions or need additional information regarding the above, conact Jordan Stout (907) 271-2776 or at jordan_stout@fws.gov.
Signed Ann G. Rappoport Field Supervisor. |
Louis Howard |
| 4/30/2003 |
Document, Report, or Work plan Review - other |
EPA Kevin Oates provided comments to the Air Force (C. Mayer) re: RI/FS Draft for DP98.
The document will benefit from a thorough technical editing review. There are numerous instances noted in the specific comments of contradictory statements in the document. The results & interpretation of the remedial investigation, human health, & ecological risk assessments need to be clear & consistent in order to support identification of a preferred alternative(s) in the proposed plan, as well as any selected remedial action(s) in the Record of Decision.
The discussion of the application of screening criteria is inconsistent. At different places in the document it is indicated that preliminary screening of potential contaminants of concern was undertaken by comparison to USEPA Region 9 preliminary remediation goals (PRGs) & in other locations it was undertaken by comparison to preliminary chemical-specific ARARs. In previous comments & discussions, EPA has indicated that preliminary screening of contaminants of potential concern (COPCs) against Region 9 PRG’s should be the first step in developing a list of contaminants of concern (COCs). Comparison to chemical-specific ARARs also needs to take place to ensure that even if no adverse risks are found, compliance with ARARs is addressed.
Page ES-4. GW Modeling. Second sentence. The text states that based on modeling concentrations of chlorinated solvents & fuel contaminants above preliminary ARARs are expected to reach the wetland within 5 years. The previous page indicates that TCE levels in one sample & RRO levels in two samples already exceed screening criteria. In this case the screening criteria are based on 18 AAC 75, which is an ARAR. This needs to be reviewed for consistency & the text corrected to reflect that contaminants have apparently already reached the wetland.
Given that the fate & transport modeling does not take into account continuing source terms from the smear zone or natural attenuation, what is the benefit for the RI/FS of these modeling efforts? How will they be useful in evaluating technologies & remedial alternatives given these limitations?
Section 6
The approach taken in this part of the RI/FS report for identification & application of screening criteria is to use preliminary State & Federal chemical-specific ARARs as “screening criteria”. The text also states on page 6-2 that these criteria are not meant to imply cleanup levels. This is not an accurate statement in the context of comparison of concentration of contaminated media to promulgated cleanup standards. Furthermore, the text indicates that for some media preliminary ARARs were used...”in the absence of federal screening criteria.” This is also not accurate. In discussions on previous submittals, EPA has provided comments to the effect that EPA has published extensive risk-based screening criteria (RBSC) including the Region 9 PRG tables.
Those PRGs & the RBSCs when used for preliminary screening steps to identify COPCs are typically established at incremental cancer risk levels on 1x10E-7 & hazard quotients of 0.1. Many of the preliminary chemical-specific ARARs are based on less conservation values &/or technology issues. In discussions with the USAF on these topics, it was generally recognized that the primary COCs have been detected over a wide range of concentrations, including those well above chemical-specific ARAR levels. It was also generally agreed to that DRO & TCE are the primary risk drivers at the site.
The lack of a step-wise method of development & screening of COPCs has resulted in an inconsistent list of COC’s by media, & in some cases inclusion of COCs that would normally have been screened out &/or dropped during risk assessment evaluations. An example of the latter is detection of arsenic in one soil sample out of 56 at 3X the background 95% UTL level. This was included as COC after the risk evaluations since it was already included as an exceedance of a state ARAR. These are two different sequential events.
Normally in the uncertainty analysis for a situation like this, an analysis would likely reflect that due to the depth of the soil sample > 10 feet bgs, & the fact that it was single hit with concentrations above & below at concentrations below the 95% UTL, it is likely to be representative of natural variability in the soil. |
Louis Howard |
| 5/27/2003 |
Update or Other Action |
Staff reviewed and commented on the draft Environmental Monitoring Plan May 2003. Main comment was on section 2.1.4 Future Direction of the RPO. Staff requested including DP98 monitoring wells into the base wide groundwater monitoring program as soon as possible. Contaminants of concern would include those which were identified in the remedial investigation/feasibility study such as: benzene, ethylbenzene, diesel range organics, gasoline range organics, vinyl chloride and other chlorinated solvents. |
Louis Howard |
| 6/3/2003 |
Meeting or Teleconference Held |
DP98 RI/FS Review conference to review response to comments submitted by EPA.
Discussion regarding Table 11-1, RAOs. URS asked Mr. Oates on how to
proceed for developing RAOs (cleanup levels) for the contaminants listed under surface
water that presented an ecological risk, as there are no regulatory criteria established for
some contaminants for surface water. Mr. Oates indicated URS should look at the
ecological risk assessment (ERA) and make sure that the eco-based exceedence exposure
path is realistic for the site. An example would be if the risk was triggered due to fish
exposure, for which it would be argued fish are not present at Site DP98. The uncertainty
analysis section of the ERA needs to be re-evaluated and bolstered. Mr. Williamson also
indicated that DRO and RRO should not be included in Table 11-1 under surface water.
URS agreed and will remove these contaminants from the Table. Changes will be made
to reflect EPA and Air Force comments and this updated Table 11-1 will be included into
the Proposed Plan.
Discussion regarding use of land use controls and how to reference these in the
RI/FS and the Proposed Plan. The Air Force and EPA agreed that general reference to
land use controls for now would be the best approach. Text will be re-written to refer to
the LUC Management Plan for ElmendorfAFB for Site DP98. The Air Force will update
this Plan to reflect the required LUCs for Site DP98 (groundwater restrictions, digging
restrictions).
MR. Oates requested the point of contact for Region 10 EPA in Seattle to which
the URS HH risk assessors are working with in regards to Comments and responses to #
51 and 52.
|
Louis Howard |
| 6/11/2003 |
Meeting or Teleconference Held |
MEMORANDUM FOR FILE FROM: 3 CES/CEVR SUBJECT: Minutes, Remedial Project Manager Meeting, 11 June 2003
A quarterly meeting of the remedial project managers (RPMs) convened at 1430L on 11 Jun 03 in the Environmental Flight (CEVR) conference room, Building 5312. Mr Louis Howard (Alaska Department of Environmental Conservation (ADEC», Mr Kevin Oates (Environmental Protection Agency (EPA) - Anchorage), Mr Gary Fink (CEVR), Mr Joe Williamson (CEVR), Ms Donna Baumler (CEVR), and Ms Doris Thomas (Public Affairs (3WG/PA» attended. Mr. Claude Mayer (CEVR) joined the meeting via teleconference. Mr Jim Klasen (Legal (11AF/JACE) was attending a training course and was unable to attend.
DP98, Land Use Control Issues (Ms Baumler). Ms Baumler stated that the Land Use Control (LUC} Management Action Plan (MAP) was completed in January. It has been updated to include information for DP98. A signature page for the Environmental Protection Committee (EPC) Chairman also has been added. In the future, we plan to have a wing instruction to assist in the enforcement of the MAP. Ms Baumler provided copies of the DP98 inserts which incorporate Mr. Howard's review comments regarding continuous implementation of institutional controls. The MAP will go to the EPC Chairman for signature and should be ready for distribution by the end of the month.
DP98, 2 Jul Meeting for Proposed Plan (Mr Mayer). Mr Mayer stated that the proposed 2 Jul date
would coincide with the date comments were due from agencies and would provide an opportunity to
meet with the contractor to resolve any issues.
Mr. Oates commented that the date would work with his schedule and reminded us that he would be gone in 31 days. He agreed that the meeting would be beneficial. Mr Oates made a few remarks about the Proposed Plan. He said some new issues have arisen in the last few years, such as groundwater analysis of 1,4-Dioxane. This chemical was sometimes used as a stabilizer for different types of ethenes. Mr Howard stated that detection requires a different method of analysis from the type we currently use.
Mr. Williamson said that we would add the new analysis to the Basewide Groundwater Monitoring Program next year.
Mr. Oates stated that EPA also suggested that their hydrogeologist should conduct a peer review of the Proposed Plan. Mr Oates' response to the suggestion was that the peer reviews conducted by the Air Force (USAF), the Air Force Center for Environmental Excellence (AFCEE) and ADEC were sufficient. The Proposed Plan Meeting is scheduled for 0900L on 2 July.
DP98, Discussion of Contingency Remedies (Mr Mayer and Mr Williamson). The preliminary draft ROD currently discusses the need for contingency remedies should monitored natural attenuation (MNA) not work as planned. Additionally, the preliminary draft ROD describes what triggers would implement the contingency. Mr Williamson stated that the difficulty in providing this information in the ROD is that we're unable to predict what types of remedial technologies might be available in the future. Mr Oates stated that the Five-Year Review process is designed to determine if remedies remain protective; discovery that a remedy is no longer protective would require the USAF to seek another remedy.
He stated that a discussion of possible contingency remedies could be included in an Operations and Management Plan. Mr Williamson suggested using a Remedial Action/Remedial Design (RA/RD) scope of work as an alternative to an Operations and Management Plan. Mr Oates agreed. He stated that it isn't a question of whether MNA will work, as he is certain that it will, but whether MNA will work in the amount of time we expect.
As it stands, contingency remedies will not be presented in the ROD. The ROD will indicate that contingency remedy could be implemented should rate of natural attenuation decline significantly. The decision for implementing a contingency remedy would occur as part of future five-year reviews. The RA/RD Scope of Work or RA Completion Report would outline what conditions would be necessary to trigger a contingency remedy. |
Louis Howard |
| 6/19/2003 |
Risk Assessment Report Approved |
Risk assessment incorporated into RI/FS final version which was received and approved. The total RME cancer risk and noncancer hazard index for the civilian building worker were 3 x 10-3 and 84, respectively, above USEPA’s target health goals.
The drinking of groundwater is a hypothetical future scenario contributing 88 percent to total groundwater risks and 99 percent to the total hazard index. The RME tap water ingestion cumulative cancer risk of 3 x 10-3 and hazard index of 83 both exceed USEPA’s target health goals of 1 x 10-4 and 1. Evaluation of risks and hazards under the current scenario of inhalation of volatile contaminants in indoor air resulted in a risk of 4 x 10-4, also above USEPA’s target health goal, but a total hazard index of only 0.5. Of the 17 COPCs evaluated in groundwater, only the following contaminants make up greater than 95 percent of the total hazard index and have HQs greater than 1: cis-1,2-DCE and TCE; and only three contaminants make up greater than 95 percent of the total cancer risk and have cancer risks greater than ADEC’s target risk level of 1 x 10-5: tetrachloroethene, TCE and vinyl chloride. Both cancer risks and the noncancer hazard index are overwhelmingly driven by one chemical, TCE.
As was the case for civilian building worker risks and hazards, the total cancer risk of 5 x 10-4 and the noncancer hazard index of 84 for the military building worker are due almost entirely to ingestion of groundwater as a future tap water source. The cancer risk and hazard index resulting from exposures to volatile contaminants in indoor air of
6 x 10-5 and 0.5, respectively, were below USEPA’s target health goals of 1 x 10-4 and 1. No contaminants in soil were considered a health concern for the construction worker, and no contaminants were identified as COCs.
Of the contaminants evaluated in groundwater, only TCE had an individual hazard index greater than 1. The cumulative TCE hazard index of 7 is due almost entirely to dermal exposures (97 percent). The exceedances over the target health goals is unlikely to be a concern due to the many conservative assumptions that were made in the estimation of construction worker risks. For example, a skin surface area of 3,300 cm2 assumes that the forearms and the whole head is exposed. In Alaska, because of extreme weather conditions, a construction worker is more likely to have less skin exposed than the average construction worker. In addition, dewatering is likely to take place during construction activities, thus reducing direct exposure to groundwater. Therefore, contaminants in groundwater are not likely a significant health concern for construction worker exposures. However, because TCE cancer risks and hazards exceeded target health goals, it was identified as a COC for this scenario. Contaminants in soil were generally not a health concern for residential exposures and no contaminants were identified as COCs in soil. All three of the pathways evaluated for groundwater (ingestion, dermal contact, and inhalation of vapors) resulted in cancer risks greater than target health goals. The majority of cancer risks were driven by the inhalation pathway at 5 x 10-2 (contributing 81 percent), followed by the ingestion pathway at 1 x 10-2 (contributing 18 percent), and finally the dermal pathway at 3 x 10-4 (contributing less than 1 percent). Total RME child and child/adult noncancer hazard indices were 875 and 476, respectively. As was the case with total cancer risks, all three pathways evaluated resulted in both child and child/adult hazard indices greater than target health goals. The ingestion pathway contributed most to total hazards with child and child/adult hazards of 544 and 295 (contributing 62 percent), followed by the inhalation pathway with child and child/adult hazards of 323 and 176 (contributing 37 percent), and finally the dermal pathway with child and child/adult hazards of 8 and 5 (contributing less than 1 percent).
Ecological risk: For soil, no contaminant concentrations exceeded their associated RBSCs (Table I-2). No soil contaminants are identified as COPECs to be passed forward to the baseline risk assessment for further evaluation.
All detected soil contaminants in the 0 to 2 feet bgs surface stratum have RBSCs available. Therefore, there are no soil contaminants whose risks could not be quantified, which eliminates a potential source of uncertainty in the EcoRA. For fresh surface water, there were no contaminants which exceeded its RBSC and therefore no risk could be calculated for surface water at DP98.
For sediment, rooted macrophytes and benthic invertebrates have been selected as the target ecological receptors exposed to contaminants in sediment. Sediment had two contaminants exceed their associated RBSCs: 2-methylnaphthalene and fluorene (HQ 13 and 4.3 respectively). |
Louis Howard |
| 6/19/2003 |
Site Characterization Report Approved |
Remedial investigation/feasibility study (RI/FS) final version received and approved. Groundwater modeling was conducted as part of the RI/FS. BIOCHLOR was the chosen groundwater model to estimate migration time and concentrations for solvent contaminants. The goals of this modeling effort were as follows:
• Estimate the distance that the TCE plume in groundwater would travel downgradient of the presumed source area.
• Estimate if degradation of the TCE plume in groundwater would be achieved below applicable regulatory levels before reaching the wetlands.
• Validate assumptions made in the 2001 EE/CA regarding natural attenuation in groundwater.
BIOCHLOR was selected as the modeling tool to evaluate the reactive transport of both “parent” and “daughter” chlorinated solvents at Site DP98. The model accounts for dispersion, adsorption, advection, and sequential biotransformation. The reductive dechlorination of the parent solvent (PCE) to daughter product is assumed to be a first-order process. The model assumes that biotransformation starts immediately downgradient of the source and that no biotransformation of dissolved constituents in the source area occur.
As with any computer-based modeling program, BIOCHLOR has a number of known limitations. As an analytical model, BIOCHLOR assumes a simple groundwater flow condition. Because of this assumption, hydraulic gradient and conductivity values need to be calculated as a site average. The model should not be applied where pumping systems create a complicated field flow. Additionally, applying BIOCHLOR where vertical flow gradient affects contaminant transport is not recommended.
BIOCHLOR also assumes uniform hydrogeologic and environmental conditions over the entire model area. BIOCHLOR simplifies site conditions (hydrogeological and biological values) and assumes constant source for the entire model area. It should be noted that complex hydrogeological conditions are present at Site DP98 resulting in greater uncertainty in modeling results.
Finally, BIOCHLOR was designed for the simulation of sequential reductive dechlorination of chlorinated ethanes and ethenes.
The model results indicate that a TCE groundwater concentration of 0.005 mg/L will reach the wetlands in approximately 5 years (after 1999), assuming biodegradation. If the actual degradation rates were higher than input into the model, the downgradient extent of the plume would be less than modeled. This could also explain why the actual PCE plume is significantly less than the TCE plume. Additionally, TCE could have been transported overland with the DRO emulsion, resulting in a larger plume relative to the PCE plume. TCE and DRO are present at the base of the slope and edge of the wetland, which confirms the results of the groundwater model.
The cis-1,2-DCE retardation factor is lower than the TCE retardation factor, and as a result, cis 1,2-DCE migrates through the groundwater faster than TCE.
The lateral extent of the shallow groundwater zone beyond Site DP98 and the extent of contamination beyond the site are unknown. Because groundwater emerges at ground surface less than 300 feet downgradient of the assumed source area, complete degradation of TCE and daughter compounds is not occurring. Volume calculations and percent change were not calculated because the groundwater emerges at ground surface (i.e., the model is being run within too small of an area to address complete degradation; however, the size cannot be increased because groundwater emerges at the wetlands).
In summary, the model results show that the plume is migrating downgradient at the site, and natural degradation is occurring. The model predicts that complete breakdown is not possible based on the limited area of migration that is upgradient of groundwater flow into the wetland. However, the model overstates the mobility of PCE and its daughter products. There is ample evidence of naturally occurring degradation as indicated by the presence of cis-1,2-DCE and VC.
Unlike the mass flux calculations that estimate a time for a dissolved contaminant mass to migrate through a section of the aquifer, the BIOCHLOR model results estimate concentrations downgradient of the source over time. The calculations suggest that no less than 137 years, at a minimum, would be required before all of the dissolved DRO in groundwater migrated from the Facility area to the wetland area. It is estimated to take approximately 29 years, at a minimum, for all of the dissolved TCE to migrate from the upper elevated area to the wetland area. It should be noted that these estimates do not take into consideration continued contribution of TCE and DRO contamination from soils above the groundwater saturation zone or TCE dissolved in DRO emulsion, which contain high levels of these contaminants. |
Louis Howard |
| 7/28/2003 |
Update or Other Action |
Memorandum for the record to C. Mayer USAF from PACAF Bioenvironmental Engineering flight. RE: Air Monitoring at Bldg. 18224. 1. On 18 Jul 03, Lt Lee and TSgt Bensel from the Bioenvironmental Engineering flight accomplished screening air sampling for Trichloroethylene (TCE) in Building 18224. This air
sampling was accomplished due to a request from the Environmental Protection Agency (Mr. Kevin Oates) to monitor indoor airborne levels of trichloroethene (TCE).
2. The air sampling was performed with a Miran 205B Series SapphiRe (SN 205B75872381) portable ambient air monitor from Thermo Environmental Instruments. The unit was field
calibrated and zeroed on the day of the survey. Results of the screening samples are listed in the table below.
Time Sample location and Results in ppm
1430 Backgund reading outside Bldg 18224 (4 to 5 ppm)
1433 Room 9 (hall area) Background
1440 Room 10 (racquetball court) Backgrund
1445 Room 11 (small storage area) Background
1450 Room 13 (tool storage) Background
1455 Room 8 (store room) Background
1500 Room 7 (snow melt store room) Background
1505 Room 5 (UPS room) Background
1510 Room 6 (open bay area) Background
1515 Door 2 (mech., room) Background
1520 Door 3 (store rom) Background
1530 Sub basement (7 ppm)
3. Our results indicate only one area inside the building with airborne levels above background levels, The sub basement was 2 ppm greater than background readings. These levels do not
pose a significant health hazard to any personnel. It should also be noted that there is no office space therefore no personnel routinely inhabit the building.
According to employees they may go into the building once per week for under an hour. Most trips into the facility are under 15 minutes.
4. Based on the buildings current usage and our screen sample results no significant health hazard to employees for the short period of time they enter the building. If there are any questions concerning this survey please contact me at 552-3866 or TSgt Bensel at 552-3985. Signed Henry Cabrera, Maj. USAF, BSC, OIC, Environmental Protection. |
Louis Howard |
| 8/20/2003 |
Proposed Plan |
Staff reviewed and approved the proposed plan for DP98. The facilities at the site were built in the early 1950s and consist of several buildings and support structures. DP98 also includes undeveloped land north of the facilities. DP98, located on the northwest side of the base, contains both petroleum hydrocarbons and chlorinated solvents in the soil and groundwater. The contamination is the result of past spills, leaks and activities at an old vehicle maintenance shop. Petroleum hydrocarbons were likely released to soil and groundwater from leaks and overfilling of the original USTs that serviced Building 18224. These leaks migrated down through soil to groundwater. Chlorinated solvents were most likely released from Building 18224 when it was used as a vehicle maintenance shop.
The preferred alternative consists of a combination of the following: limited soil excavation with monitored natural attenuation of groundwater, off-site disposal of excavated soils, and maintenance of existing land use controls. The public comment period on the DP98 Proposed Plan will begin on September 1, 2003 and end on September 30, 2003. Written comments about the protectiveness of the remedies may be sent to the base environmental community relations’ coordinator, MSgt. Jon K. Scudder, until September 30, 2003.
An open house will be held September 25, 2003 from 7 to 8 p.m. at the Sheraton Anchorage Hotel, 401 E Sixth Ave, Anchorage, Alaska. A public comment session will follow from 8 to 9 p.m. |
Louis Howard |
| 12/15/2003 |
Update or Other Action |
Staff reviewed and commented on the draft record of decision for DP98. Staff concurred with the document in its present form having been involved in many rewrites and review meetings beginning in the spring of 2003. Management has been kept informed throughout the ROD development and their comments have been incorporated. The selected remedy will involve removal of the chlorinated contaminants in soil that are acting as a source material, constituting a principal threat because of high contaminant concentrations and subsurface mobility. The remaining soil and sediment contaminants will be remediated via natural attenuation. Monitored natural attenuation (MNA) will be used to remediate groundwater containing chlorinated contaminants and petroleum contaminants that represent the principal threats to human health and the environment.
Soils contaminated with chlorinated compounds within an approximate 25-foot radius from the outlet of the drywell drain system north of Building 18224 will be removed. Soil will be excavated down to ten feet or to the water table, whichever is encountered first. Assuming that the soil from ground surface to five feet below ground surface (bgs) is not contaminated, the soil volume proposed for this limited removal is estimated to be approximately 360 cubic yards.
If during the five-year review period, monitoring data indicate that contaminant concentrations in groundwater do not continue to decline as estimated in the modeling predictions, the Air Force, USEPA, and ADEC will reconsider the remedy decision. |
Louis Howard |
| 2/9/2004 |
Document, Report, or Work plan Review - other |
EPA comments on the Draft ROD.
RCRA Waste Designation. The ROD needs to clearly state that the VOC contamination is not associated with the listed waste under RCRA. VOC contaminated soils may still need to managed as RCRA wastes depending on TCLP results.
Passive tense (use of the word “would”) should be corrected to active tense (“will”) throughout most usage in the ROD. This appears to be an artifact from the RI/FS report where actions are evaluated in the context of what is possible. In a ROD actions are evaluated & a remedy selected in terms of what will be done. There are other examples, that are more page specific where RI/FS language was used that needs to be modified to meet ROD language. As noted in comment 11 below, it will be beneficial to address these through text redline/strikeout.
GW & MNA. The ROD needs to have more information on the lines of evidence that show how & where natural attenuation is occurring, & where there may not be the data to support this (i.e. below the 190 foot contour line). In addition, all of the information required by the April 1999 OSWER policy (OSWER Directive Number 9200.4-17P) needs to be summarized in the ROD. Places where this could be include are: in the nature & extent section; alternatives evaluation; or in the selected remedy. Please note that section 5.2 provides a good start, but it does not address all of the requirements of the policy.
Scope of Treatability Study during RD/RA. In regard to information below the 190 foot contour line, the ROD needs to be clearer that the “treatability study” work includes some additional characterization of the subsurface in the vicinity of & down gradient of the 190 foot contour line. It is not consistently presented that it includes not just an evaluation of the addition of carbon source, but also some limited characterization work of subsurface dynamics related to MNA. Finally, the ROD should describe the goal of this work in terms of determining if subsurface condition are/are not conducive to dechlorination processes.
Source Soil Excavation & Offsite Disposal/Treatment. There needs to be a better description of the rationale for the 25 foot approximate radius for excavation, as well as the 10 foot depth. For the latter, the ROD should describe the fact that the tile drain is buried approximately five feet below grade, therefore the top five feet is expected to be uncontaminated. The results of field investigation for this should also be cited. For both the radius & the depth, known information concerning concentration gradients & estimates (if available) for mass of contamination reduction that is expected to be realized based on the limited soil source removal/treatment/disposal portion of the selected remedy.
POL Contingencies Post-VOC Remediation. The ROD discusses follow on actions for petroleum contaminants in terms of contingency measures &/or as remediation needed as separate from the VOC remedy. Under this description, this would make the current ROD as written an interim action for DP-98. The project team needs to discuss this in the context of the overall strategy for addressing site releases, as well as the interface of the CERCLA FFA program, & the State USAF two party agreement.
Screening Levels. The text at several locations refers to “screening levels” in the context of evaluation of contaminants of concern. The text needs to identify the basis/source of the screening criteria when they are first introduced in order to place them in context in later discussions. Screening Levels. The text at several locations refers to “screening levels” in the context of evaluation of contaminants of concern. The text needs to identify the basis/source of the screening criteria when they are first introduced in order to place them in context in later discussions.
Page 3, second set of bullets. It is premature to state that two consecutive rounds of sampling with no exceedances is sufficient to determine that cleanup goals have been met with the current level of uncertainty associated with site conditions for MNA, particularly down gradient of the 190 foot contour. The stopping rule decisions will likely need to be developed as part of the five year evaluation process described by the draft ROD for evaluating the MNA process, timeframes, & fate & transport models
|
Louis Howard |
| 2/9/2004 |
Document, Report, or Work plan Review - other |
Additional EPA Legal Counsel Comments on DP-98 draft ROD (M. Queitzsch).
Page1 of Part I - The wording of the “Assessment of the Site” should be revised to read as follows: “ The response action selected in this ROD is necessary to protect the public health or welfare or the environment from actual or threatened releases of hazardous substances into the environment. Such a release or threat of release may present an imminent and substantial endangerment to public health or welfare or the environment.”
Page 7-3, 7-5, 7-27 of Part II - It is somewhat unclear in this section after the presentation of the Summary of Contaminants of Potential Concern for Each Medium in Table 7-1 as to why there was no discussion of TCE in the wetland surface water in the exposure assessment, the risk characterization, and the COCs for groundwater and surface water. If TCE is not of concern for surface water, it is suggested that a sentence explaining why be added to page 7-2.
Page 9-13 of Part II - The LUCs are all written in the passive future tense and this tense should be revised throughout. For example, the following statement: “LUCs at DP98 would include restrictions on groundwater use and digging” should be changed to: “LUCs at DP98 include restrictions on groundwater use and digging” or perhaps “prohibit the use of groundwater and restrict digging at the site.”
Table 13-1 of Part II - The location specific ARAR concerning the National Register of Historic Places list is too general and suggests that an eligibility assessment occurred. While the act may be an ARAR, the details in the documentation block are overstated. |
Louis Howard |
| 2/23/2004 |
Update or Other Action |
Staff concurred with the request to extend the submittal date from February 20, 2004 to April 15, 2004. As outlined in the Federal Facility Agreement Administrative Docket Number 1089-07-19-120, Section XXV Extensions, the Department concurred that there was good cause to grant the Air Force an extension on the submittal of the DP98 draft final Record of Decision. |
Louis Howard |
| 3/15/2004 |
Document, Report, or Work plan Review - other |
EPA comments on the draft DP98 ROD.
General.
1. LUC Consistency. LUC consistency. Declaration page 6 states that LUCs are to maintain current land uses at DP-98. The selected remedy at Page 12-14 states that the land use will remain exactly as it is now until cleanup levels are achieved (75 years). In other places the ROD talks about the process to change land use, & notification of the agencies. It would appear tha the first passages cited in this comment are very prescriptive & would not allow for any other uses for 75 years. Is this the intent, or is more flexibility desired ?
2. Elimination of SW. The ROD in some locations has eliminated discussion of surface water as a media of concern, & in other places has retained surface water as a media of concern. It is also clearly listed as a compliance measurement point. Recommend a technical review of the ROD to ensure that surface water is maintained as a media of concern. It is also important to very clearly identify that many of the sediment/surface water sampling locations are at emphemeral seeps. This should be described in Section 5.2. A description along the lines of…”The wetland area receives runoff water in the spring. The rest of the year it is dry, & in the winter is frozen.” Could be inserted after the second sentence of the second paragraph in this Section. It was also be beneficial to note that sampling at the Kettle Pond showed no exceedances of cleanup levels.
3 Removal of POL information. It has been agreed that POL remedy information will be removed from this ROD. However, in some location there remain descriptions of nature & extent (this may be appropriate for context) such as figures 5-1 amd 5-2. In other areas, it has been removed from the text (i.e. Section 5.4.2 GW. There should be a consistent approach for the discussion of the presence of POL in the affected media. There is some logic to leaving in the discussions regarding nature & extent. It could also be noted in Section 5 that the results of the investigation are presented for context only & that the ROD does not address risks or remediation of POL.
Specific.
1. Declaration. Page 1. Please re-instate the original language under Assessment of the Site. This is generic language that is present in all Region 10 RODs, including previous Elmendorf AFB RODs. It is also statutory definitions
2. Declaration Page 2. Under the description of MNA, recommend adding the following language at the end of third sub-component. “to assess the effectiveness of MNA.”
3. Declaration page 3. 1st bullet. Recommend inserting language describing the logic why soil samples for MNA will not be taken until GW remediation levels are achieved. This could be achieved by moving the passage 2 paragraphs below this in the text to this bullet. Also, for that text below, recommend adding the word “further” before…”characterization of the soil….” This would help put this in context that characterization efforts have been made during the EE?CA & RI/FS investigations. Same comment for text at Page 9-4 under monitoring requirements. Same comment also for page 12-5, bullet # 4.
4 Declaration page 3. Treatability Study. Recommend rewriting the 2nd sentence as follows. “The limited data collection to date indicates an uncertainty about the effectiveness of natural attenuation around & down gradient of this contour level.”
5 Declaration page 3. Last sentence. Recommend adding the word “GW” prior to “observations in Section 12.2.2.3…”
6 Declaration page 4. Duration/Termination of MNA. 1st paragraph, last sentence. Recommend rewriting as follows. “Surface water that is downgradient of the site & is believed to be in contact with GW from the site will be monitored….etc”
7 Declaration page 4. Duration/Termination of MNA. 3rd para, 1st sentence. Editorial. Insert the words “source area” after “excavated”.
8 Declaration Page 6. LUCs. The 1st bullet includes a statement that contaminated soil that exceeds Table 8-1 levels is excavated it cannot be transported or disposed of at another location on base. The text would benefit from a statement on where it could be transported to & disposed of. Same comment for page 9-3, first bullet.
9 Declaration page 7. 2nd para, 1st sentence. Please rewrite as follows to be consistent with March 15th wording agreement for page 12-20 between Allison Abernathy & Marc Trost. “The Air Force shall provide notice to the USEPA & ADEC as soon as practicable, but in no case more than 10 days after if it discovers any activity….etc”
|
Louis Howard |
| 6/23/2004 |
Cleanup Level(s) Approved |
The chemical specific ARARs for contaminants of concern are as follows which were memorialized in the Record of Decision for this site for soil (18 AAC 75.341): 1,1-Dichloroethene 0.03 mg/kg, cis-1,2-Dichloroethene 0.2 mg/kg, Tetrachloroethene 0.03 mg/kg and Trichloroethene 0.027 mg/kg. The sediment cleanup levels are:
cis-1,2-Dichloroethene 0.2 mg/kg and
Trichloroethene 0.027 mg/kg.
Groundwater (MCL 40 CFR 141.61): 1,1-Dichloroethene 0.007 mg/L, cis-1,2-Dichloroethene 0.07 mg/L, Trichloroethene 0.005 mg/L, Tetrachloroethene 0.005 mg/L, and Vinyl Chloride 0.002 mg/L.
The remedial action objectives (RAOs) for DP98 are to protect human health and the environment from exposure to contaminated soil, groundwater, and sediment. A principal objective is restoration of the groundwater underlying the site to a potential beneficial use as a drinking water source. The basis and rationale used to form the RAOs include the following:
High contaminant concentrations in the soil acting as source materials for groundwater
contamination are principal threats; The RME and anticipated future land use scenario used in the HHRA include unlimited and unconditional use (e.g. residential land use); and Drinking water is the potential future beneficial use for groundwater underlying the site.
The RAOs for DP98 are as follows: Reduce chlorinated solvent concentrations in soil, sediment, and groundwater to chemical specific
ARAR; Select remedial action alternatives that will minimize the damage to the wetland ecology; Prevent exposure (via ingestion, inhalation, and/or dermal contact) to groundwater until such time as the federal and state drinking water standards are met;
Restrict excavations and the installation of water wells to reduce the possibility of exposure to contaminants and contaminant migration from the contaminated aquifer to the
uncontaminated aquifers; and Maintain current land use designations at this site. |
Louis Howard |
| 6/23/2004 |
Institutional Control Record Established |
The specific land use controls (LUCs) at DP98 are as follows:
Excavating, digging, or drilling in the area shown on Figure 9-1 is restricted to reduce the
possibility of migration or exposure to contaminants that exceed the chemical-specific
ARARs in Table 8-1. If contaminated soil that exceeds chemical-specific ARARs is
excavated, it cannot be transported to or disposed of at another location on base. Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of CERCLA waste under the Off-site Disposal Rule (40 CFR §300.440). No dewatering of excavations or trenches will be allowed unless contaminated water is treated prior to use or disposal. Any excavations or drilling greater than ten feet bgs will require engineering controls to prevent downward migration of contamination and to protect the groundwater aquifer.
•The use of contaminated groundwater throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control or any other activity, is prohibited.
The current land use as shown on Figure 9-1 will be maintained to reduce the possibility of
exposure to contaminants.
The Air Force is responsible for implementing (to the degree controls are not already in place), monitoring, maintaining, reporting and enforcing the identified controls. If the Air Force determines that it cannot meet specific LUC requirements, it is understood that the remedy may be reconsidered, and that
additional measures may be required to ensure the protection of human health and the environment.
The Base General Plan will include the specific LUCs identified in Section 12.2.3, the current land uses
and allowed uses of the site, and the geographic LUC boundaries. The section describing the specific
controls will also refer the reader to the Base Environmental Flight if more information is needed.
The Base General Plan will contain a map indicating locations of LUCs at DP98 and the associated LUCs for each area. The Air Force will notify USEPA and ADEC 30 days prior to making any changes to the Base General Plan, which could affect these restrictions and controls.
The Air Force shall seek prior concurrence from USEPA and ADEC to (a) terminate LUCs, or (b) modify current land use(s). In addition, the Air Force shall seek prior concurrence before any anticipated action that may disrupt the effectiveness of the LUCs, or any action that may alter or is inconsistent with the
land use assumptions or land uses described in this ROD. |
Louis Howard |
| 6/23/2004 |
Long Term Monitoring Established |
With the signing of the ROD, long term monitoring will commence. After the first five years of groundwater monitoring, the Air Force will evaluate the progress of MNA.
This evaluation will compile, analyze, and review all data collected, including information from the RI/FS, the MNA identified in Section 12.2.2.1, and the Treatability study identified in Section 12.2.2.2 to determine the effectiveness of MNA. Additional groundwater modeling will be completed to provide
updated estimates for the time frames to meet the cleanup goals.
If during this evaluation, the data indicates contaminant concentrations in groundwater are not declining as estimated, the Air Force, USEPA, and ADEC may reconsider the remedy decision. One or more of the following observations could lead to reconsideration of the remedy:
• Increase in parent contaminant concentrations indicating that other sources may be present;
• Concentrations of parent contaminants and/or daughter products may indicate that the
estimated cleanup time frames may not be reached; and
• Plume of primary contaminants and/or daughter products increases significantly in aerial or vertical extent and/or volume from that predicted by modeling estimates.
These observations could trigger the implementation of enhanced monitored natural attenuation.
Under the selected remedy, MNA will continue until groundwater contamination is no longer a threat to human health and the environment, verified by two years of consecutive sampling events where analytical results show that the COCs are less than the chemical-specific ARARs in Table 8-1. Sampling for
individual groundwater COCs may be discontinued at any time two sampling events show concentrations are below chemical-specific ARARs. However, during the final two rounds of groundwater monitoring,
samples will be collected and analyzed for all of the COCs in Table 8-1. Surface water that is
downgradient of the site and is believed to be in contact with groundwater from the site will be monitored until such time as all groundwater COCs meet chemical-specific ARARs.
Once it has been verified the groundwater COCs are below chemical-specific ARARs, confirmational sampling will be conducted to verify that soil and sediment COCs are below associated chemical-specific ARARs in Table 8-1. Currently, it is estimated natural attenuation will clean up groundwater within 35 to 75 years and soil outside the excavated source area within 18 to 48 years. Two methods, fate and transport mechanism for
chlorinated solvents in groundwater and mass flux calculations, were used to estimate the time frames to meet the cleanup levels through MNA. These estimates may be revised once the evaluation identified in Section 12.2.2.3 is completed.
Fate and transport modeling using BIOCHLOR computer software demonstrated that natural attenuation of chlorinated solvents and fuel contaminants is occurring in the unconfined aquifer. Model max flux calculations suggest it would take at least 137 years for all of the dissolved DRO and 29 years for all of the TCE to migrate from the site to the nearby wetland. These estimates do not account for continued contribution of contamination from soils above the groundwater saturation zone or natural attenuation of the contaminants. |
Louis Howard |
| 6/23/2004 |
Record of Decision |
Final Record of Decision for DP98 received on August 16, 2004 with all three agency signatures. Victor E. Renuart Jr. Lieutenant General USAF Vice Commander Pacific Air Forces signed on June 17, 2004, ADEC John Halverson signed on June 23, 2004, EPA Kathryn M. Davidson, Acting Director, Environmental Cleanup Office, Region X signed on July 22, 2004. The selected remedy for DP98 addresses a source area that has released the following chlorinated contaminants: trichloroethene (TCE), tetrachloroethene (PCE), cis-1,2-dichloroethene (DCE), 1,1-DCE, and vinyl chloride.
The remedy will address the potential threat to human health and the environment from contaminated soil, sediment, and groundwater. The remedy will excavate and dispose of contaminated soil, which will remove chlorinated contaminants in soil that are acting as a source material, constituting a principal threat because of high contaminant concentrations and subsurface mobility. The remaining soil and sediment contaminants will be remediated via natural attenuation.
Monitored natural attenuation (MNA) will be used to remediate groundwater containing chlorinated contaminants that represent a principal threat to human health and the environment. Excavation will be limited to soil within a 25-foot radius of soil boring DP98-SB01, where the greatest TCE concentrations were detected, adjacent to the end of the drain tile north of Building 18224. The lateral limits of excavation were established using conservative estimates based upon the lateral extent of soil contamination around the tile drain. Based on available data, the 25-foot radius around the soil boring encompasses the lateral zone with the highest TCE concentrations.
Soil will be excavated down to 10 feet or to the water table, whichever is encountered first. Assuming the soil from the ground surface to 5 feet below ground surface (bgs) is not contaminated due to the depth of the end of the drain tile, the soil volume for this limited removal and treatment is estimated to be 360 cubic yards. Excavated soil will be transported to a treatment, storage, and disposal facility in the lower 48 states that is acceptable for disposal of CERCLA waste under the Off-site Disposal Rule (40 CFR §300.440). Clean soil (i.e., laboratory analyzed) will be identified and used for backfilling the open excavation. One construction season is estimated to be required for the limited source removal.
The MNA component of the remedy has three sub-components: 1) natural attenuation of contaminants in groundwater, soil, and sediment; 2) a treatability study to determine the effectiveness of the natural attenuation at/around the 190-foot topographic contour; and 3) an evaluation/compilation of groundwater data collected during the first five years of monitoring. After completion of the source removal, a treatability study will be undertaken in the area of the 190-foot topographic contour to evaluate the effectiveness of natural attenuation. The limited data collection to date indicates an uncertainty about the effectiveness of natural attenuation around and downgradient from this contour level.
Land Use Controls (LUCs) are an integral part of the remedy. The LUCs are designed to prevent activities that could affect the performance of the other components of the remedy, prevent the migration of contaminants in groundwater, and maintain current land uses to protect human health and the environment. |
John Halverson |
| 7/26/2004 |
Update or Other Action |
Remedial Process Optimization Evaluation July 26-29, 2004
This document reports the results of a Remedial Process Optimization (RPO) evaluation that was performed at Elmendorf Air Force Base (AFB), Alaska from July 26 to 29, 2004. The RPO effort focused on four sites: Fairchild Plume, Slammer Plume, Site DP98, & Site ST36/66.
The nature & extent of fuel hydrocarbons & chlorinated solvents has been adequately defined for the purposes of this RPO evaluation. However, the total depth of soil & GW contamination should be reviewed in the event that any full-scale engineered remedial action or confirmation sampling for closure by MNA is conducted. Elmendorf AFB will be collecting additional data in 2004 for 1) the base-wide GW monitoring program, & 2) to support a Phase I TS microcosm study to assist in evaluating enhanced bioremediation as a contingency measure. Specific data gap recommendations for the base-wide monitoring program & for conducting the microcosm study are described in respective subsections below
The LTM plan should focus on two objectives: 1) performance of the proposed remedy to reduce contaminant mass & concentrations, & 2) compliance at potential points of exposure (e.g., sentry wells). It is important to note that upgradient & downgradient monitoring locations that do not exhibit measurable concentrations of contaminants of concern provide little useful information on performance of the proposed remedy.
Seven wells have been proposed for sampling in 2004 (Table 2.2), which represent the current LTM locations used for annual monitoring. These locations consist of an upgradient well & three contingency wells; locations that provide no useful information for performance monitoring. The Team recommends that the number of upgradient & contingency monitoring wells sampled be reduced, & that the sampling frequency at these contingency wells be decreased, while increasing the number of wells useful for establishing concentration trends & mass reduction.
The ROD for DP98 also states that monitoring of seep locations on an annual basis is required. The seep sampling locations should likewise be reviewed to ensure they provide useful & meaningful data to support the MNA remedy.
Preliminary screening of site data indicates that geochemical conditions and the distribution of dechlorination products of PCE and TCE are favorable for an enhanced anaerobic bioremediation TS. To fill data gaps for site-specific screening and conceptual design, the team recommends that additional field data be collected from monitoring wells WL-02, WL-04, and WL-05 during sampling for the Phase 1 microcosm study. The Team recommends collection of methane, ethene, and ethane (MEE); volatile fatty acids (VFAs); dissolved organic carbon (DOC, filtered samples); phospholipid fatty acids (PLFAs, unfiltered turbid samples); and molecular screening for Dehalococcoides species (unfiltered turbid samples) using quantitative polymerase chain reaction (PCR).
Verification of MNA is based on multiple lines of evidence (USEPA Chlorinated Solvent Protocol, 1998), using direct contaminant data & indirect geochemical data. Conversely, compliance with the ROD is based solely on meeting contaminant concentration ARARs specified in the ROD. The Team recommends the calculation of biodegradation rates, use of trend analysis such as linear regression techniques, evaluation of changes in molar ratios & total molar concentrations, & use of mass based calculations as methods to evaluate the progress of natural attenuation of chlorinated solvents at DP98.
These analysis are based on concentration data for the COCs at the site, which should be collected at a frequency sufficient to establish statistical trends. Once a contaminant plume is relatively stable, most geochemical & other indirect parameters used to document MNA do not tend to change dramatically over time. Therefore, indirect indicators of MNA (supplemental MNA analyses in Table 2.3) do not need to be collected on as frequent a basis as the COCs at the site.
Predictive models for MNA are most accurate when steady state geochemical conditions & biodegradation rates are maintained. Depletion of the primary carbon source at DP98 (fuel hydrocarbons) & enhanced rates of biodegradation due to the enhanced bioremediation field test will make predictive numerical GW modeling difficult, if not impractical The use of analytical models such as BIOCHLOR (chlorinated solvents) or BIOSCREEN (fuel hydrocarbons) may provide a range of time for MNA to reduce concentrations to compliance levels, at a much lower cost & similar confidence as that of a numerical model The evaluation of MNA progress should also include the use of mass- or flux-based tools being developed for AFCEE
|
Louis Howard |
| 8/11/2004 |
Update or Other Action |
The Alaska Department of Environmental Conservation (ADEC) has received the draft copy of the work plan on August 5, 2004. ADEC will not and cannot comment on the health and safety plan referenced in Appendix B. Instead, ADEC will keep it on file for our records.
The work plan for DP98 site characterization and limited treatability study phase of the project is approved as submitted, pending EPA comments being incorporated into the document. |
Louis Howard |
| 9/15/2004 |
Update or Other Action |
EPA (Kevin Oates) comments on the Limited Hot Spot Removal WP
1. General comment. The document is titled as a hot spot removal work plan (WP), but it describes tasks that are more reflective of remedial design activities. Specifically, it describes data collection to better define the area for soil excavation in 2005. In addition, it describes data collection to conduct a bench scale treatability study to evaluate larger scale options to enhance the monitored natural attenuation (MNA) portion of the selected remedy for DP-98. EPA anticipates that a WP will be required for the soil excavation & offsite treatment activities that will take place in 2005. It appears the USAF has included an additional WP in the schedule (Figure 2-1) for this activity. In addition, there is a need for a more detailed description of the treatability study. This should include descriptions of the type of set up to be used (columns, shakers, etc); complete listing of analytical parameters; schedule of the sampling regime to evaluate MNA parameters, etc.
2. General Comment. Treatability Study. It is not clear from the information presented in the draft document that there is sufficient information to proceed to Phase 3 of the RABITT protocol. It would be useful to include information &/or references to the RI/FS & other reports that document the information on the stratigraphy & hydrology at DP-98. The following excerpt from the RABITT Protocol reflects the importance of this information.
“3.4.3. Hydrogeologic Profile. The success of RABITT depends on the effective distribution of electron donor & nutrients throughout the subsurface, consequently the ability to control the movement of GW is imperative. The large point value assigned to hydraulically conductive aquifers in Table 3.2 reflects this necessity. Sites with a hydraulic conductivity less than or equal to 10-5 cm/sec have been assigned an exceptionally low score to supercede any other positive site conditions. At such sites, the difficulties in distributing electron donor through the subsurface would make implementation of RABITT infeasible even under the most promising microbial & geochemical conditions. Because many hydrogeological parameters are subjective (e.g. stratification), & because an averaged hydraulic conductivity accounts for several other hydrogeological variables, hydraulic conductivity is the only criterion used for
the purposes of numerically rating a site’s hydrogeologic potential. Other less quantifiable factors (e.g. stratigraphy) must be defined & accommodate before RABITT implementation begins.”
The hydraulic conductivities measured at DP-98 should be reported as to number, values, harmonic mean & some indication of where in the stratigraphic column they were measured. If significant heterogeneities have been observed in soil borings emplaced to date, then values for the sediment package as a whole should be developed & compared to the Phase 2 RABITT Protocol screening guidelines to ensure there is sufficient information to support proceeding to the next phase.
More information on the RABITT Protocol can be found at:
http://www.estcp.org/documents/techdocs/Rabitt_Protocol.pdf
3. Page 1-1. Section 1.0, fourth bullet. The project team needs to discuss what will constitute enhancements that will “markedly increase resulting contaminant degradation.”
4. Page 1-9, last sentence in section 1.2.1.8. The text would benefit from a statement that describes the results of analytical sampling in the lower aquifer formation. As it reads now, the text states there is some degree of communication between the upper & lower aquifer formations, but does not state if there is any contaminant transport.
5. Page 1-10, last paragraph, first sentence. The words “cleanup level” should be substituted for “screening level”. The cleanup level of 0.027 mg/kg for TCE was selected in the DP-98 ROD pursuant to 18AAC75.341. See Section 11 & Table 8-1 of the ROD.
6. Page 3-1. Paragraph two. The text describes taking random samples for TCLP tests. EPA recommends a stratified sampling approach that includes biased samples in the areas of known/suspected highest level. A purely random sampling regime runs the risk that areas of high level would not be subject to TCLP during the remedial design sampling efforts presented in the work plan. This could lead to a presumption that during soil excavation & offsite disposal soils would not have to be handled & managed as potentially hazardous (characteristic) wastes pursuant to state & federal regulations. It is not clear if the intent of the TCLP testing is to better inform decisions on how to manage transport & dispose of soils excavated in 2005. EPA encourages the USAF to undertake a sampling regime in 2004 that will better inform excavation & disposal activities in 2005. This is discussed further in the following comment.
See file for additional information. |
Louis Howard |
| 9/21/2004 |
Document, Report, or Work plan Review - other |
AF Response to EPA Comments on the DP98 Limited Hot Spot Work Plan
Accepted. The 2004 work plan will be renamed DP98 Soil Characterization and Treatability Study Work Plan to more accurately reflect the work to be performed.
The 2005 work plan will be retain the name DP98 Limited Hot Spot Removal.
Accepted. Additional information will be provided on the treatability study in the SAP (Appendix A).
In terms of the treatability study, this project will essentially conduct Phases I-III of the RABITT protocol. The intent is to collect sufficient data to support the follow-on field demonstration using AFCEE and RABITT protocol guidance. The implementation of Phase IV of the treatability study will be conducted in 2005 under a separate contract. The work plan for that study is expected in January 2005. The design specifications will be based on the results of this year’s efforts.
Accepted. The RI/FS will be referenced accordingly.
Based upon existing data presented in the RI/FS, it is unclear if conditions are appropriate to proceed to the next phase of the RABITT protocol. Therefore, additional geophysical and geochemical data are proposed in support of the treatability study. This data will be collected concurrently with the treatability samples. Although the hydraulic conductivity is important to the distribution of the electron donor and nutrients throughout the subsurface, it may not be prohibitive of the success of the treatment. The Phase IV contractor (Parsons) will use the hydraulic conductivity data to determine the most appropriate approach to implement the treatability study. This may include the use of multiple injection points if the hydraulic conductivity is not suitable for effective distribution.
An evaluation of existing data and sample results as well as recommendations for follow-on field demonstration will be included in the 2004 Technical Report. The draft is expected in January 2005.
Noted. Phase 2 and 3 will occur concurrently. Geophysical and geochemical data will be evaluated based upon protocol screening guidelines prior to implementing the next phase of the treatability study. As stated previously, the Phase IV contractor is aware of the possibility of the hydraulic conductivity being less than the RABITT screening guidelines, and has developed an alternative injection approach to address this issue.
Accepted. A discussion will be provided of what will constitute “increase contaminant degradation”. The rate of biodegradation will be evaluated against control (non-amended) conditions to determine if enhancement may provide a significant impact to the biodegradation process.
Accepted. Text will be clarified as follows: “Based on Hydrogeologic surveys there are two distinct, stratified aquifer regions—one on top of the other. The upper zone consists of saturated Clayey, Gravely, Silty Soil (C/G/Si) and Gravely Sand (G/Sa). The lower zone consists of saturated Gravely, Silty, Sandy Soil (G/Si/Sa). The two zones are separated by a 9’ layer of Silty Clay. This Silty Clay layer tapers off toward the North and transitions from Silty Clay to Clayey Silt from East to West, which are both indicators of leakage. Based on suspected leakage (“communication”) between the two aquifers, URS conducted pump test to verify that flow did exist between the upper and lower aquifer, however it is unknown if analytical samples from the lower aquifer were collected.”
Accepted. “Cleanup level” will be substituted for “screening level”.
Accepted. The following approach is proposed. The cylindrical excavation will be divided into four quadrants with one soil boring will be advanced in to the geometric center of each quadrant. One TCLP VOC sample will be collected from each boring at 2-foot intervals and will used to characterize waste for the quadrant and depth. Each TCLP sample result will therefore represent 25yrds of soil, which is the approximate volume of one 20-foot long waste container |
Louis Howard |
| 10/6/2004 |
Update or Other Action |
Maximum contaminant levels above the cleanup levels were detected in the following wells in October 2004: Well 41755-WL02 had PCE at 1,260 ug/L, 1,1-DCE at 16 ug/L and cis-1,2-DCE at 8,030 ug/L. Well 41755-WL04 had TCE at 2,330 ug/L and Well 41755-WL05 had vinyl chloride at 16 ug/L. |
Louis Howard |
| 10/26/2004 |
Meeting or Teleconference Held |
Meeting minutes by Marty Brewer for DP98 Draft Work Plan Comment Resolution Meeting
PARTICIPANTS:
KEVIN OATES – USEPA
CURT BLACK – USEPA
MARTY BREWER – JACOBS
GARY FINK - AFCEE
ELIZABETH GODDEN – 3 CES
TERRY HEIKKILA – JACOBS
Gary began the meeting by providing an overview of the scope of the DP98 project for the calendar years 2004 and 2005. This overview was helpful for the EPA in understanding the scope of the current work plan.
Points of clarification included:
• The scope of this 2004 work plan includes the soil characterization around SB-01 for the subsequent excavation of contaminated soil in 2005. A treatability field study will be conducted in 2005 under a separate contract with Parsons. This work plan is due in January 2005.
• The excavation of contaminated soil will be covered in a separate work plan to follow based upon the results of the 2004 characterization data.
• Additionally, the first three phases of the reductive anaerobic biological in situ technology (RABITT) protocol will be conducted under the scope of the 2004 work plan (collection of baseline treatability data, evaluation of this data, and microcosm studies).
Clarification was made regarding the treatability study sample locations as well. The treatability study will occur in the vicinity of the contamination source at the 190-foot groundwater contour and the topographic 190-foot elevation. Geophysical and geochemical data will be collected and evaluated using AFCEE (AFCEE 2000) and RABITT protocol guidance prior to proceeding to the next phase of the treatability study.
Once the scope of this work plan was clarified, EPA realized that some of their treatability questions would be addressed in the follow-on work plan to be prepared by Parsons.
After this project overview, EPA was asked if there were any specific review comments that they wanted to discuss. They responded that the clarification provided by Gary addressed most of their concerns, but there were a couple issues they wanted to discuss further. These issues included:
Comment #6: EPA agreed that the revised TCLP sampling approach was an improvement over the original approach and accepted the revised approach.
Comment #8: The surface sampling and soil boring approach was clarified, and was acceptable to the EPA.
Comment #13: The budgeted excavation soil volume was briefly discussed to the EPA’s satisfaction.
Comment #25: This is the only comment in which the response has changed since they were issued. To avoid needing an equipment blank, all groundwater samples were collected using hand bailers. EPA accepted this change.
There was a discussion regarding the results of the surface soil samples, which were available for the meeting. The majority of the surface samples had detections for chlorinated solvents; therefore fewer borings would be installed than planned. EPA was fine with this as long as we had enough data to characterize the waste and determine which areas of the excavation were more contaminated than the others.
Also discussed was the high density of utilities inside the security fence. Due to the number of utilities, the dig permits prevented any soil borings from being installed inside the fence. Based on the number of utilities, Jacobs is recommending that no soil be excavated inside the fence either. Instead, we recommend the 25-foot circle centered at SB-01 be moved away from the fence in a direction that would capture the most contaminated soil. Surface soil data showed that the soil inside the fence was an order of magnitude less contaminated than the soil outside the fence, which would support relocating the circle. EPA asked for the surface soil data results, which were subsequently e-mailed to them by Jacobs. Jacobs will write the project report with this recommendation, which EPA will consider during their review. We all recognized that this would be a change from the ROD.
To conclude the meeting, all parties agreed that the work plan could be finalized with the comment responses as written and as discussed in the meeting. |
Louis Howard |
| 11/30/2004 |
Update or Other Action |
Final DP98 Soil Characterization and Treatability Study - Slug testing was performed at the DP98 site on 14 October and 21 October 2004 to determine hydraulic conductivity. Five groundwater monitoring wells (WL-02, WL-04, WL-05, WL-09, and WL-21) were chosen and slug testing was performed using the American Society for Test and Materials, Method D 4044, Test Method (field Procedure) for Instantaneous Change in Head (Slug Tests) for determining Hydraulic Properties of Aquifers (ASTM 1997). The average gradient across the site was estimated to be approximately 0.04. The effective porosity was assumed to be 0.38, a value typical of unconsolidated silts, sands, and gravels. Plausible values range from 0.3 to 0.4, a small range compared to the range of Kh values determined from the slug tests.
In situ bioremediation technology has been successfully demonstrated for remediating groundwater and soils at sites contaminated with TCE and PCE. The RABITT, an enhanced anaerobic dechlorination process, offers the potential for destruction of PCE and less chlorinated chloroethenes by the addition of an electron donor/nutrient formulation to the subsurface, eliminating aboveground treatment. The RABITT will be used as guidance in conducting the treatability study.
A bench scale treatability test will be conducted to determine the potential for using this application at DP98. The study will be done as a phased approach that allows the user to screen out RABITT in the early stages of the process to save time and cost.
Review of data obtained from previous investigations at DP98 indicates that this site meets the screening criteria under the first phase for further characterization.
The second phase requires that a candidate test plot location within the plume be selected for more in-depth characterization (organics, pH, nutrients, etc). This test plot has been determined to be located in the vicinity of the 190-foot groundwater elevation and 190-foot topographic contour. Combination groundwater and aquifer sediment samples will be collected from three existing monitoring wells and sent to RespirTek for the bench scale treatability study. The decision to proceed to the third phase of the treatability study will be based on the evaluation of the data collected during the characterization of this candidate test plot.
The third phase of the treatability study involves conducting laboratory microcosm studies. The scope of this work plan includes the first three phases of the RABITT.
The fourth phase, to be conducted under separate contract, includes the field pilot test of the electron donor/nutrient formulation determined in the laboratory microcosm studies to be the most effective for supporting biologically mediated reductive dechlorination. |
Louis Howard |
| 12/17/2004 |
Update or Other Action |
USAF (Claude Mayer) sent email to EPA (Kevin Oates), ADEC (Louis Howard), AFCEE, JACOBS staff. RE: DP98 Soil Characterization Findings.
This memo is intended to summarize the findings of the soil characterization that was recently completed & to outline our proposed approach for the completion of the source material removal at DP98.
Based on the results of this summer's expanded soil characterization, we have a much better understanding of the nature & extent of trichloroethene (TCE) contamination within the 25’ radius of soil boring DP98-SB01.
The data indicates the highest levels of TCE levels occur near the surface at a depth of 4 to 6’. As part of this expanded soil characterization, TCLP was run on numerous soil samples at various depths. None of the samples were above the TCLP hazardous waste criterion, which suggests that the chlorinated solvents are not leaching downward into GW.
These results from this summer's effort have revealed that some of the assumptions made in section 12.2.1 of the Final DP98 ROD were inaccurate. The assumptions used in the ROD were based on limited data collected during the RI. At the time the ROD was signed, it was believed the source the chlorinated solvent contamination in the soil was the drain tile & these high levels of contaminates were contributing to the GW contamination in the area.
Based on the RI data, it was assumed there would not be high levels of chlorinate solvents in the soil from the surface down to 5’ in depth & the highest levels of chlorinated solvent in the vadose zone would be at a depth greater than 5’. As a result of the assumptions, section 12.2.1of the ROD requires a limited source material removal of chlorinated solvents from the area within a 25’ radius of DP98-SB01.
As stated in the ROD, the objective of the DP98 soil source material removal is to "...remove chlorinated contaminants in soil that are acting as a source material, constituting a principal threat because of high contaminant concentrations & subsurface mobility." The DP98 ROD does not provide a chemical concentration to determine what is a sufficient concentration to constitute source material. However the DP98 ROD does give some clues or parameters on what range would likely constitute source matter.
For example, soil boring DP98-SB01 was determined to be the location of the source material based on one sample collected at approximately 8’ bgs that resulted in TCE at 3.91 mg/kg, or 145 times greater than the cleanup level. However, nearby surface soil with TCE levels at twice the cleanup level (0.06 mg/kg) were not targeted for removal. Additionally, soil samples collected at DP98-SB02 contained TCE at a maximum concentration of 1.69 mg/kg near the surface & were not targeted for removal because they were determined not to be source material.
Therefore, based upon the data presented in the RI/FS & the ROD, it is the Air Force's position the TCE in soil which constitute source material lies somewhere between 1.69 mg/kg & 3.91 mg/kg. A conservative number would be approximately 100 times the cleanup level for TCE or 2.7 mg/kg & this level would meet the objectives of section 12.2.1 of the ROD.
Using the source material criteria of 2.7 mg/kg, we have calculated the volume of soil that would be excavated. The excavation volumes were calculated by including the soil one foot above & below the depth of the sample depth (i.e., the soil targeted for removal at 2’ bgs will be excavated between the depths of 1 & 3’). The total volume of source material to be excavated is estimated at 124 cy.
Soils overburdening the source material would be excavated directly into waste bins for disposal with the source material. The volume of overburden soils to be removed in order to excavate source soils is estimated at 99 cubic yards.
Soils inside the high-security fence could not be characterized at depth due to the presence of multiple mission-critical underground utilities. In addition to the utilities, there is a buried security line present inside the fence, the location of which is classified. Our Wing Instruction 32-1007 dated 12 Jul 01 states all digging within 2’ of the marked utility will be performed by hand.
Additionally, certain communications cable may require hand digging within 3 or 4’ depending on the discretion of the Commander. These utilities would require soil excavation to be performed by hand, & any damage to the security line would impact the project.
Excavation would stop within the required distance from the utilities within the 25’ circle. Assuming the soil around the utilities is contaminated to the same degree & at the same depths as the soil tested within the 25’ circle, approximately 70 cubic yards of contaminated soil would be left in place |
Louis Howard |
| 1/20/2005 |
Meeting or Teleconference Held |
MEMORANDUM FOR FILE
FROM: 3 CES/CEVR
SUBJECT: Meeting with EPA and ADEC, 20 Jan 05
The initial reason for this meeting was to conduct a Remedial Project Manager’s meeting. Mr. Kevin Oates indicated after connecting him by phone that he would have trouble talking since he recently underwent oral surgery. It was recommended to postpone the meeting to 3 Feb 05 at 0830 Anchorage time.
I asked for a few minutes while everyone was present to discuss the memorandum sent earlier about the DP98 soil characterization findings. The data indicates the highest levels of TCE contamination within the 25-foot radius of soil boring DP98-SB01 occurs near the surface at a depth of 4 to 6 feet. Also, Trichloroethene (TCE) levels of contamination not targeted for removal were higher than soil going to be removed from the 25-foot radius of soil boring DP98-SB01. Additional comments were mentioned resulting in the following comments accepted by all parties:
1. Maximize the resources available to the AF. Remove the most contamination for the dollars available under this project. This means the circle may become an elongated circle or the circle may have bites out of it to get the highest contamination.
2. The 500cy of soil to be removed will really be based on weight (tons) and not cubic yards.
3. The utilities inside of the fence include a buried security line. Excavation would stop within the required distance for hand digging around utilities within the 25-foot circle.
|
Louis Howard |
| 1/20/2005 |
Update or Other Action |
The characterization report recommended a slight modification to the excavation circle to avoid utilities and still remove the targeted quantity of soil, which was accepted by ADEC and U.S. Environmental Protection Agency and documented in a January 20, 2005 Memorandum.
Memorandum for File from: 3 CES/CEVR Subject: Meeting with EPA and ADEC 20 Jan 05. The data from the DP98 Soil characterization findings indicates the highest levels of TCE contamination within the 25-foot radius of soil boring DP98-SB01 occurs near the surface at a depth to 4 to 6 feet. Also, trichloroethene (TCE) levels of contamination not targeted for removal were higher than soil going to be removed from the 25 foot radius of soil boring DP98-SB01. Additional comments were mentioned resulting in the following comments accepted by all parties:
1. Maximize the resources available to the AF. Remove the most contamination for the dollars available under this project. This means the circle may become an elongated circle or the circle may have bites out of it to get the highest contamination.
2. The 500 cubic yards of soil to be removed will really be based on weight (tons) and not cubic yards.
3. The utilities inside of the fence include a buried security line. Excavation would stop within the required distance for hand digging around utilities within the 25 foot circle. |
Louis Howard |
| 2/3/2005 |
Meeting or Teleconference Held |
Memorandum for File from 3 CES/CEVR. A quarterly meeting of the remedial project managers (RPMs) convened at 0830 on 3 Feb 05 in the Environmental Flight (3 CES/CEV) conference room, Building 5312. Mr. Louis Howard (Alaska Department of Environmental Conservation (ADEC)), Mr. Joe Williamson (Environmental Restoration (CEVR)), Mr. Gary Fink (CEVR), Mr. Claude Mayer (CEVR), Ms. Ellen Godden (CEVR), and Ms. Donna Baumler (CEVR) attended. Mr. Kevin Oates
(Environmental Protection Agency (USEPA) - Anchorage) joined via teleconference.
Program Update
a. Groundwater (GW) Remedial Process Optimization (RPO) Recommendations (Mr. Fink). Mr. Fink explained that we asked an outside team to look at the Fairchild and Slammer TCE plumes. Previous modeling efforts left data gaps and too many uncertainties. It was unclear if monitored natural attenuation (MNA) was progressing at the rate required to meet our projected cleanup dates. Additionally, we asked the team to review the recently developed long-term monitoring plan for DP98, to determine if we were taking the correct approach. As far as DP98 is concerned, the RPO team suggested some sampling well points but no outstanding recommendations.
b. DP98, Update on Microcosm Study (Mr. Fink). As a recap, the microcosm study contains two phases, the microcosm study this year and fieldwork next year. The microcosm study has been running about 90 days. The lab shows little to no activity. Jacobs Engineering has the contract and Parsons has been acting as a technical advisor. The field data shows dechlorination, and Parsons believes we may not have gotten a representative sample of the microbial population in our samples. At their suggestion, we have split the microcosm study into batches. In some, we raised the temperature, in others we bioaugmented with additional microbes. Others were bioenhanced with lactate and soy. The lab will run the split samples for another 60 - 120 days.
c. DP98, Annual Land Use Control (LUC) Report (Ms. Godden). Section 12.2.3.4 of the DP98 ROD states that the Air Force will submit timely annual monitoring reports on the status of LUCs to USEP A and ADEC. The report has been drafted and is at Legal (llAF/JACE) for review. We anticipate that the report will be complete by 18 Feb 05 and will be distributed to the agencies at that time.
Update on Zone implementation (Mr. Williamson). We began the break out into zones (1,2, and 3) last May. By 1 Oct 06, the change will be fully implemented. Currently, the RPMs are preparing FY06 programming documents for their respective zones and have been reviewing documents for their zones since last summer. The change should improve the whole process of document review and site management. Groundwater will be broken into zones, but Mr. Fink will retain a basewide report.
Quarterly Progress Reports (QPRs) (Mr. Williamson). Mr. Oates and Mr. Howard confirmed that the information they receive in the report, in its current format, is quite useful to them when they are briefing their higher headquarters. Both agreed that we could reduce submittals to semi-annual reports, which will be submitted in December and May. Mr. Howard requested that we continue to break sites out by Operable Unit since that is the way their database has been designed to track. |
Louis Howard |
| 2/22/2005 |
Update or Other Action |
Air Force sent the 2004 DP98 Annual Monitoring report on the status of land use controls (LUCs) at DP98 as required by Section 12.2.3.4 of the DP98 Record of Decision dated June 17, 2004.
Specific LUCs at DP98 are as follows:
Excavating, digging or drilling is restricted to reduce the possibility of migration or exposure to contaminants that exceed chemical specific applicable or relevant and appropriate requirements (ARARs). If contaminated soil that exceeds chemical specific ARARs is excavated, it cannot be transported or disposed of at another location on base. Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of CERCLA waste.
The use of contaminated groundwater throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control, or any other activity, is prohibited.
The current land use will be maintained to reduce the possibility of exposure to contaminants.
The specific LUCs identified above, the current land uses and allowed used of the site, and the geographic LUC boundaries have been added to the Base General Plan.
Site inspections and site visits were conducted using a standard 3 CES/CEVR Site Inspection worksheet. Each inspection indicated that activities in the DP98 area are consistent with LUC requirements, objectives, or controls and that the activities have not interfered with the effectiveness of the LUCs. No deficiencies in the LUCs were identified during the 2004 calendar year. No corrective actions are required, and the LUCs remain protective of human health and the environment. |
Louis Howard |
| 2/28/2005 |
Update or Other Action |
Staff commented on the DP98 Treatability Study Work Plan for Enhanced Monitored Natural Attenuation at DP98 Elmendorf AFB, Alaska February 2005 received on February 15, 2005. Staff declined to comment on the health and safety plan referenced in Appendix B. Instead, it will keep it on file for our records.
The work plan for DP98 Treatability Study for Enhanced Monitored Natural Attenuation was approved as submitted, pending EPA comments being incorporated into the document. |
Louis Howard |
| 3/1/2005 |
Update or Other Action |
Staff reviewed and approved the draft Soil Characterization report for DP98. Results from the surface and subsurface soil samples indicate that TCE and its daughter products are found at very high levels in the proximity of SB-01. Chlorinated solvents were detected in almost every sample location. TCE ranged from 0.00677 to 11.000 mg/kg, PCE ranged from 0.0048 to 0.270 mg/kg and VC was detected in one sample at 0.0077 mg/kg. Because TCE levels are high in all quadrants of the 25 foot radius circle, the majority of this soil is recommended for excavation and disposal. Because of results of TCLP analysis, it is recommended that the soil removed be classified as non-hazardous. It is recommended in the document that the excavation perimeter be slightly modified, rather than excavating a full 25 foot radius circle. Soil within the circle, which is a safe distance away from any utilities, per excavation permit requirements, should be excavated and disposed of off-site. Soil that cannot be excavated because of utilities should be supplemented by removal of contaminated soil along the edge of the northwest quadrant of the circle, which exhibited higher concentrations of contamination. The volume of soil to be removed would remain approximately the same as originally planned. |
Louis Howard |
| 3/4/2005 |
Document, Report, or Work plan Review - other |
EPA Questions on DP98 unexpected TCE in surface soils
Collectively we have talked about the unexpected TCE positive hits above cleanup levels in the surface soils. After reading the report, I have some ideas to explore that may shed some light on the reported results. I noticed that many of the "detects" for TCE in surface soils coincide with the road sample locations. The road is indicated as being a six inch asphalt bed in the boring logs in Appendix A.
This raises at least two questions in my mind about the validity of the reported data.
1) The first one concerns the composition of the surface soil samples from this area.
If the samples contained some, or a lot of asphalt (and asphalt has a high percentage of petroleum products including VOCs), what we could be seeing is matrix interference that is yielding false positive results.
Even if the 0-6" samples from the road area were taken below the road (there are no notes to indicate whether the samples were 0-6" from the top of the road or 0-6" of "native soil") there would still be a good chance of some asphalt being in the sample matrix.
2) The second question in my mind is why are there no QA/QC sample results the Appendix B?
In the absence of the results for trip blanks, splits, MS, MSD runs, there is no way of knowing if the results reflect a problem with the sample collection, collection jars, etc.
You may have already noticed that pattern of distribution of TCE contamination is quite different between the surface samples and the subsurface sample results under the raod, as well as away from the road and near the end of the drain. The contamination profile is more consistent away from the road. I think that there are good reasons to question the reported results and the true areal distribution recommended for excavation of source materials as required by the ROD. |
Louis Howard |
| 3/11/2005 |
Update or Other Action |
Letter from Jacobs regarding the DP98 Soil Characterization Report-Analytical Data. Near Surface TCE results-Unexpected TCE (trichloroethene) hits in surface soils were actually expected. Jacobs believes that the elevated concentrations of TCE detected under the asphalt may be a function of the asphalt layer acting as a cap, trapping the volatile TCE compound. There appears to be little if any evidence of interference related to asphalt road bed material to TCE results. |
Louis Howard |
| 3/18/2005 |
Document, Report, or Work plan Review - other |
EPA Kevin Oates reviewed and commented on the DP98 Soil Characterization Report.
1. Executive Summary. Page ES-1. The sentence regarding detected levels are indicative of a need for remedial action seems out of place. First the ROD for DP-98 already established the need for remedial action. Second the reported levels from the most recent soil characterization effort reports levels for PCE & Vinyl Chloride that are below ROD cleanup levels. Only TCE was detected in soils above ROD cleanup levels.
2. Executive Summary. Page ES-2. In regard to the statement that “all soil removed during the 2005 removal action will be classified as nonhazardous.”, EPA would like to know how soils associated with the sample that showed TCE at 11 mg/kg performed in the TCLP procedure. In the event that soils from the area of highest level were not subject to TCLP analysis, EPA cannot support this statement. It is difficult to discern if this is the case or not from the text & attached data. See EPA comment # 6 on the DP-98 Limited Hot Spot Removal WP for further discussion on this topic.
3. Page 1-1. Section 1.1, 1st para. Recommend replacing “removal” with “remedial” in the second line since this action is being taken pursuant to a CERCLA ROD.
4.Page 1-1. Section 1.1, 1st para. Recommend replacing “desire” with “ROD requirement” in the fourth line since this action is being taken pursuant to a CERCLA ROD.
5. Page 1-2. 2nd para under Sect. 1.2. It would be more accurate to state the location of site DP-98 as west of Fairchild Ave. It is not in the location described in the text.
6. Page 1-12. Last sentence. The text here states that it is unknown if analytical samples were collected from the lower aquifer during the 2002 field season. This needs to be a definitive statement that samples either were or were not collected, & if samples were collected what the results are from the analytical work.
7. Page 1-13. 3rd para. The text here talks about the results of soil sampling. It states that “TCE at DP98-SB01 was detected at 0.5 to 1.5 feet bgs (1.69 mg/kg)”. Figure 1-3 indicates that these are the results for soil boring DP98-SB02. Please review for consistency & accuracy. Revise as needed.
8. Figure 1-4. The units for the two GW level contour maps need to be changed to mg/L. They currently are listed as mg/kg.
9. General Comment on the section & subsections on previous investigations. This information is summarized in other reports. Most recently in the DP98 Limited Hot Spot Removal WP. Repeating this summary information in this document does not add value to the understanding of the conditions found during the recent effort to define the area for excavation in the remedial action. In the case of the subsections on page 1-19, there are inaccurate or incomplete summary statements concerning the results of GW modeling & the risk assessments conducted during the RI/FS. These are discussed further in the next comments. Recommend that in future documents the USAF present the information that is germane to the issues for discussion.
10. Page 1-19. GW modeling results. The first sentence in this section states that natural attenuation of chlorinated solvents & fuel was demonstrated to be taking place by the BIOCHLOR model. Models do not demonstrate what is actually happening in the ambient environment. Media sampling demonstrates & validates or verifies computer predictions associated with rates of events, such as natural attenuation. It is not clear why there is a brief summary of GW modeling from the RI/FS in a report to present RD level soil characterization information.
11. Page 1-19 Risk Assessment Summary. Again, it is unclear how this summary adds to information on RD level soil characterization information. There are several places
in the text here where inaccurate representations of the results of the risk assessment are presented. Recommend reviewing & revising as appropriate the statements concerning “health concerns”. Recommend using CERCLA language for risk assessments regarding potential human health risks. Please explain what is meant by “risks & hazards that exceed target health goals.”
12. Section 1.4.9. Recommend putting all the selected remedy components in this section to provide context for the soil excavation portion. Also, if the text will talk about the treatability study, recommend putting that in the correct context. MNA is known to be occurring at some locations at the site. The treatability study is intended to evaluate enhancements to areas further downgradient where geochemistry results do not favor MNA, & do not indicate it is taking place.
13. Page 2-1. Last two sentences. Recommend putting these in the context of being ROD cleanup requirements.
See file for additional information. |
Louis Howard |
| 3/21/2005 |
Update or Other Action |
Limited hotspot removal action work plan received to excavate and containerize approximately 500 cubic yards of contaminated soil from DP98. |
Louis Howard |
| 3/21/2005 |
Update or Other Action |
2004 Phase I RPO Annual Report Groundwater Performance Optimization Monitoring Program received. . Because of the limited amount of COC results present, many of the modeling activities being prescribed for subsequent plumes cannot be performed at the DP98 Plume. It is recommended modeling efforts be performed at this plume when the requisite input data are available. Analytical results from the DP98 Plume suggest PCE and TCE daughter products have not displayed an appreciable increase. However, results of the MNA evaluation indicate natural attenuation is reducing COC concentrations at this plume. Reductive dechlorination of chlorinated organic compounds such as PCE and TCE is occurring, and it is probable that existing fuel constituents are being used to cometabolize these chlorinated solvents.
Because MNA sample results indicate natural attenuation is removing chlorinated solvents from local groundwater and COC results are not adequate to accurately model this plume, no wholesale performance monitoring changes are recommended for the DP98 Plume. Recommended monitoring changes for the DP98 Plume are minimal and are detailed below:
COC monitoring: Figure 12-1 in the DP98 ROD was created to guide sampling frequencies at the DP98 Plume. Use of MAROS to optimize COC monitoring at this plume is not recommended because sample results are not adequate to meet the minimum input requirements. The DP98 ROD decision guide should be used to direct COC monitoring until MAROS can be properly utilized.
MNA monitoring: To ascertain COC levels, MNA monitoring is currently performed at each well that is sampled. MNA samples are also collected at the same frequency at which these COC samples are collected. It is recommended that these two sampling suites be disconnected. MNA samples should only be collected from wells 41755WL-01, 41755WL-02, 41755WL-05, 41755WL-17, and 41755WL-12. The number 41755WL-01 represents the upgradient well to be used for MNA evaluations. A line can then be drawn from 41755WL-01 through the other four wells that bisect the plume and terminates outside the plume boundary at well 41755WL-12. This line also approximates the direction of groundwater flow at this plume, thereby increasing its value as an MNA monitoring network. It is recommended MNA monitoring continue on an annual basis.
Cleanup date predictions: Although the ROD allows remedial activities to proceed at this plume until 2079, it is recommended the cleanup date for this plume eventually be reevaluated with modeling software. An additional round of sampling data needs to be collected to use Tier 2 of the SourceDK program to predict a cleanup date for this plume. It is recommended a new cleanup date for the DP98 Plume be calculated only when enough data has been collected to properly use SourceDK Tier 2.
Contaminant mass calculations: It is recommended contaminant mass calculations not be calculated for the DP98 Plume at this time. SourceDK Tier 2 will be used to predict a cleanup date when enough sample events have been performed. When implemented to predict a cleanup date, this software will also calculate the contaminant mass. It is recommended contaminant mass calculations be performed only when SourceDK Tier 2 can be properly utilized.
Treatability study: A natural attenuation treatability study is being performed to evaluate the effectiveness of enhanced bioremediation techniques at this plume. An evaluation of the microcosm at this site is ongoing. It is recommended this treatability study continue because the results from the study will augment existing knowledge of MNA performance at this plume.
Remedy protectiveness summary: The ROD mandated that 5-year reviews be performed at this plume to evaluate the performance of the selected remedy (source removal and disposal followed by MNA) and to determine whether the selected remedy is protective of human health and the environment. The next 5-year review is due to be performed in 2008. MNA and COC sample results indicate the remedy should be considered protective. Plume expansion is not occurring; natural attenuation is removing contaminants; and potential downgradient receptors are not being exposed to groundwater contaminants. |
Louis Howard |
| 3/29/2005 |
Interim Removal Action Approved |
Staff received on March 21, 2005 a work plan for a limited hotspot removal action at DP98. The removal action was identified in the May 2004 Record of Decision. The selected remedy for DP98 addresses a source area that has released the following chlorinated contaminants: trichloroethene (TCE), tetrachloroethene (PCE), cis-1,2-dichloroethene (DCE), 1,1-DCE, and vinyl chloride. The remedy is part of a basewide effort to clean up CERCLA contaminated areas. The selected remedy for DP98 will address the potential threat to human health and the environment from
contaminated soil, sediment, and groundwater. The remedy will excavate and dispose of contaminated soil, which will remove chlorinated contaminants in soil that are acting as a source material, constituting a principal threat because of high contaminant concentrations and subsurface mobility. The remaining soil and sediment contaminants will be remediated via natural attenuation. Monitored natural attenuation (MNA) will be used to remediate groundwater containing chlorinated contaminants that represent a principal threat to human health and the environment. The selected remedy will reduce contamination at
the site to attain the chemical-specific applicable or relevant and appropriate requirements (ARARs) established for DP98.
Excavation will be limited to soil within a 25-foot radius of soil boring DP98-SB01, where the greatest TCE concentrations were detected, adjacent to the end of the drain tile north of Building 18224. The lateral limits of excavation were established using conservative estimates based upon the lateral extent of soil contamination around the tile drain. Based on available data, the 25-foot radius around the soil boring encompasses the lateral zone with the highest TCE concentrations. Considering the depth to groundwater, soil will be excavated down to ten feet or to the water table, whichever is encountered first.
Assuming that the soil from the ground surface to five feet below ground surface (bgs) is not contaminated due to the depth of the end of the drain tile, the soil volume proposed for this limited
removal and treatment is estimated to be approximately 360 cubic yards. Excavated soil will be transported to a treatment, storage, and disposal facility in the lower 48 states that is acceptable for
disposal of CERCLA waste under the Off-site Disposal Rule (40 CFR §300.440). Clean soil (i.e., laboratory analyzed) will be identified and used for backfilling the open excavation at DP98. It has been estimated that one construction season will be required for the limited source removal. |
Louis Howard |
| 3/31/2005 |
Update or Other Action |
Air Force proposes changes to the DP98 Limited Hot Spot Removal WP: Use of Super Sacks for Waste Characterization
Page 3-8;
Section
3.4.3
In order to minimize removal costs, waste
will be directly loaded from the excavation
into bins and handed over to the DRMO
(Section 3.3.6 of the WMP [Appendix C]).
Page 3-9;
Section
3.5.1
Excavated soil will be placed directly into
top-loading waste containers on chassis.
Each container will be loaded with
approximately 16 to 17 cy of soil or a depth
of no more than 3 feet of uniformly
distributed material in a 20-cy container.
Pavement located in the excavation will be
broken up and placed in the soil waste
containers for disposal.
Page 3-11;
Section
3.5.2
If removal is required, the drain system will
be crushed and placed into a waste bin
with contaminated soil.
Page 3-13;
Section
3.5.6
The soil will be placed in an estimated 60
top-loading and line waste containers on
chassis.
Appendix C
Page 2-1;
Table 2-1
In approximate quantities column:
60 containers
Appendix C
Pages 3-1
and 3-2;
Section 3.2
As soil is removed from the excavation, it
will be placed directly into a 20-foot top-
loading container with chassis for
transportation and waste disposal
purposes, Once the container is filled,
Jacobs will cover the container and
transport it to the temporary staging
location, Containers will not be filled to
capacity in order to meet the weight
restriction, Containers will be filled with 16
to 17 cy of soil, or to a depth of no more
than 3 feet of uniformly distributed material
in a 20-cv container.
Appendix C
Page 3-2;
Section 3.4
Containers to be used during this RA
include 20-foot, top loading containers on
chassis (provided by the DRMO) and 55-
gallon drums, All waste turnover will be
coordinated with the DRMO, which will
ensure that all top-loading containers on
chassis and drums meet all of the following
criteria.
NEW TEXT
Page 3-8;
Section
3.4.3
In order to minimize removal costs, waste will
be directly loaded from the excavation into
Super Sacks® and handed over to the DRMO
(Section 3.3.6 of the WMP [Appendix Cll.
Page 3-9;
Section
3.5.1
Excavated soil will be placed directly into
Super Sacks® Each container will be loaded
with approximately 0.8 cy of soil. Pavement
located in the excavation will be broken up and
placed in the Super Sacks® for disposal.
Page 3-11;
Section
3.5.2
If removal is required, the drain system will be
crushed and placed into a Super Sack® with
contaminated soil.
Page 3-13;
Section
3.5.6
The soil will be placed in an estimated 625 1
cy Super Sacks®.
Appendix C
Page 2-1;
Table 2-1
625 SuperSacks®
Appendix C
Pages 3-1
and 3-2;
Section 3.2
As soil is removed from the excavation, it will
be placed directly into a 1 cy Super Sack® for
for transportation and waste disposal purposes,
Once the container is filled, Jacobs will
transport it to the temporary staging location~
Containers will be filled with approximately 0.8
cy of soil.
Appendix C
Page 3-2;
Section 3.4
Containers to be used during this RA are l£'i
Super Sacks® and 55-gallon drums, All waste
turnover will be coordinated with the DRMO,
which will ensure that all containers and drums
meet all of the following criteria:
|
Louis Howard |
| 4/15/2005 |
Document, Report, or Work plan Review - other |
EPA (Kevin Oates) Comments on the Draft DP 98 Limited Hot Spot Removal Action Work Plan. March 2005.
1. General Comment. The title of this document should replace the word “removal” with “remedial” in order to be consistent with terminology under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Record of Decision under CERCLA for site DP98 hot spot soils.
2. Section 1.4 represents a more succinct description of information that is necessary at the RD/RA work plan level than some previous submittals. EPA appreciates this more concise approach for presentation of information that is relevant to the remedial actions.
3. Section 1.4.2. This section needs to make a definitive statement regarding the results of the 2003 investigations for the lower aquifer. The text needs to state one of the following conclusions;
Sampling was or was not conducted
Results indicated that cross contamination has occurred
Results indicated that cross contamination has not occurred
Results are inclusive at this time.
4. Page 1-8. The text here states that the DP-98 ROD indicates that the source area excavation for chlorinated solvents will be limited to a 25 foot radius of soil boring DP98-SB01. This is based on the expected greatest “mass of contamination” for the source term. The Project Team has discussed the need for flexibility in terms of relying on actual field conditions (i.e. existence of buried utility lines, presence of security fences, readiness operations, etc.,) to ensure that the actual excavation and treatment of contaminated source materials is executed in the most cost-effective manner. This will likely require a certain amount of real-time interface between USAF, the USAF remediation contractors, and EPA and ADEC. EPA encourages the USAF to consider this aspect not only in the context of meeting the CERCLA requirements in the DP98 ROD, but also in the context of identification, selection, and execution of contract vehicles since there remains a certain amount of uncertainty associated with final source area soil volumes that will; a) provide the greatest source term reduction; and b) provide the greatest reduction in life cycle costs for follow on action such as monitored natural attenuation. EPA recognizes and commends the USAF for the contract contingencies that have been built into the RD/RA process to date to address these issues.
5. Please see EPA previous comments on remedial investigation and remedial design soil sampling for the potential that some soils containing chlorinated solvents may have concentrations that represent hazardous characteristic levels under RCRA. In particular, EPA has asked the USAF to examine the procedures utilized to segregate and undertake stratified sampling recommended in earlier comments for areas of higher known chlorinated solvent concentrations. It is not clear from the documentation provided to date that the USAF has under taken a process that would identify higher areas of contamination, extract media samples from these areas for TCLP analysis, and then make the appropriate determinations as to whether wastes should be managed as solid wastes or hazardous wastes under RCRA, and under RCRA as an ARAR under CERCLA. |
Louis Howard |
| 5/2/2005 |
Update or Other Action |
DP98 Soil Characterization Report summarizing the Phase I soil characterization activities at DP98. This report summarizes the phase one soil characterization activities at the DP98 site located
on Elmendorf Air Force Base. Jacobs Engineering Group Inc. performed this work for the Air Force Center for Environmental Excellence and their customer, the U.S. Air Force 3rd Civil
Engineer Squadron under the Worldwide Environmental Restoration Contract. Field activities were conducted in September and October 2004.
This project included characterization of soil contaminated with chlorinated solvents near the 381st Intelligence Squadron Buildings, also referred to as the DP98 site. The purpose of the soil characterization was to determine the severity and extent of chlorinated solvent contamination in the vadose zone around soil boring SB-01 in preparation for phase two remedial action planned in 2005.
Analytical results indicated that trichloroethylene (TCE) and its breakdown products are found at very high levels near SB-01. Chlorinated solvents were detected at almost every sample location tested and were seen in each quadrant of a 25-foot-radius sampling circle centered at SB-01. TCE levels ranged from 0.00677 to 11.000 milligrams per kilogram (mg/kg). Tetrachloroethylene (PCE) was detected at levels ranging from 0.0048 to 0.0270 mg/kg. Vinyl chloride (VC) was detected in one sample at 0.0077 mg/kg. The cleanup levels for TCE, PCE, and VC are 0.027, 0.03, and 0.009 mg/kg, respectively, thus TCE was the only compound detected above cleanup criteria established in
the Record of Decision (ROD). Remedial action will be taken at the site in accordance with the ROD.
Due to a high concentration of utilities, complete removal of the area screened during phase one is not recommended. Soil excavation is recommended within the circle, keeping a safe
distance from the utilities, per excavation permit clearance requirements. The excavation circle will likely be slightly modified to avoid the utilities and still remove the target quantity of
contaminated soil.
Soils samples were collected from each quadrant of the sampling circle and subjected to toxicity characteristic leaching procedure analysis to determine soil disposal classification. Borings were advanced 10 feet, with samples collected at 2-foot intervals. Analytical results indicated that contaminants of concern were detected at levels below the hazardous waste classification for all samples (0.5 mg/L for TCE, 0.7 mg/L for PCE, and 0.2 mg/L for VC).
Therefore, all soil removed during the 2005 removal action will be classified as non-hazardous.
The ROD assumed that the top five feet of soil at the excavation site would be clean. As a result, it was estimated that approximately 360 cubic yards of soil would require removal. The
results of the soil characterization, however, show that the top five feet of soil is contaminated; therefore, all soil excavated from the site will require disposal. The new estimated excavation quantity is 500 cubic yards.
A plausible explanation for the surface and near-surface soil contamination is that the chlorinated solvents are volatizing up from the deeper soils. This explanation is supported by the fact that the near surface soils beneath the pavement contain higher concentrations of chlorinated solvents than the non-paved locations. It is believed that the pavement is acting as a cap, trapping the gases in the soil. |
Louis Howard |
| 5/23/2005 |
Update or Other Action |
DP98 Limitied Hot Spot Remedial Action Work Plan (FINAL)-The objective of this project is to remove up to 500 cy of chlorinated solvent-contaminated soil characterized in 2004. Project activities include mobilization, site access, security fence relocation, temporary road installation, excavation, confirmation sampling, disposal of nonhazardous material, possible existing drain pipe replacement, fence replacement and site restoraiton. These activities are designed to assist the USAF’s desire to remediate contaminants that have the potential to affect human health and the environment. |
Louis Howard |
| 11/30/2005 |
Update or Other Action |
Limited Hotspot removal report received. Activities performed included: temporary fence installation, temporary roadway construction, existing fence section removal, excavation and containerization of approximately 500 cubic yards (cy) of contaminated soil, characterization sampling, fence replacement and site restoration.
Approximately 768 tons (512 cubic yards-based on 1.5 tons per cubic yard, 10 ft. depth and 10 to 1 slope) was excavated from the DP98 site during the 2005 field season. Soil was containerized in 1 cubic yard Super Sacks for transportation and disposal by the Defense Reutilization and Marketing Office. However, the discharge pipe or leaching field believed to be the source of the chlorinated solvent plume was not encountered during the removal effort.
Trichloroethylene was detected at levels from 0.015 to 3.1 mg/kg with 13 of the 14 samples collected exceeding the 0.2 mg/kg cleanup level in the ROD. Cis-dichloroethene also remained at or above 0.2 mg/kg ROD cleanup levels in four of the samples, with a maximum concentration of 9.0 mg/kg. Confirmation samples indicated that tetrachloroethene was below 0.03 mg/kg ROD cleanup levels and vinyl chloride was not detected. *NOTE to file: Vinyl Chloride in soil detection limits using EPA SW8260B VOC: (all units in ug/kg) 6.7, 7.0, 10, 11, 12, 13, 14, 15, 21, 25, 39, 71, and 140. 18 AAC 75.341 Table B1 Method Two Soil Cleanup Levels Table cleanup concentration is 0.009 mg/kg or 9 ug/kg. The reporting limit in all but two sampling events was higher than the cleanup level for vinyl chloride. Vinyl chloride is NOT a ROD specified contaminant of concern in soil, however it is specified as a groundwater contaminant of concern at 0.002 mg/L or 2 ug/L.
|
Louis Howard |
| 12/8/2005 |
Update or Other Action |
The Alaska Department of Environmental Conservation (ADEC) received the removal action report on November 30, 2005. After reviewing the document, ADEC will approve the document as final, pending incorporation of EPA’s comments on the document. Please provide both a hard copy and electronic copy of the final document for our files.
|
Louis Howard |
| 2/1/2006 |
Update or Other Action |
Air Force sent the 2005 DP98 Annual Monitoring report on the status of land use controls (LUCs) at DP98 as required by Section 12.2.3.4 of the DP98 Record of Decision dated June 17, 2004. Specific LUCs at DP98 are as follows: Excavating, digging or drilling is restricted to reduce the possibility of migration or exposure to contaminants that exceed chemical specific applicable or relevant and appropriate requirements (ARARs). If contaminated soil that exceeds chemical specific ARARs is excavated, it cannot be transported or disposed of at another location on base.
Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of CERCLA waste. The use of contaminated groundwater throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control, or any other activity, is prohibited. The current land use will be maintained to reduce the possibility of exposure to contaminants. The specific LUCs identified above, the current land uses and allowed used of the site, and the geographic LUC boundaries have been added to the Base General Plan.
In 2005, 3 CES/CEVR reviewed two work clearance requests. Both projects at the facility were 3 CES/CEVR projects (DP98 limited hot spot removal and DP98 enhanced treatability study). The site visits during the two projects wer conducted using work plans previously approved by the agencies. The inspection and site visits indicated that the activities in the DP98 area are consistent with LUC requirements, objectives or controls, and that the activities have not interfered with the effectiveness of the LUCs. No deficiencies were identified during the 2005 calendar year. No corrective actions are required, and the LUCs remain protective of human health and the environment. |
Louis Howard |
| 3/6/2006 |
Update or Other Action |
Staff reviewed the draft 2005 Phase I RPO Annual report. Table 2.1-7 Site DP98 Recommendations The table’s first recommendation is to drop 41755-WL05 from the program per Parsons recommendation. ADEC does not concur. This monitoring well is the only well, thus far, which shows vinyl chloride above the 2 µg/L during the last three sampling events (12 µg/L 2000, ND (22 µg/L), 15 µg/L 2004 Summer sampling event). ADEC requests the Air Force conduct sampling at this monitoring well until a baseline trend for vinyl chloride and performance metrics can be established.
|
Louis Howard |
| 7/27/2006 |
Update or Other Action |
Maximum contaminant concentrations were detected above cleanup levels in the following wells in July 2006: Well 41755-WL02 had tetrachloroethene (PCE) at 1,240 ug/L, trichloroethene (TCE) 1,870 ug/L. Well 41755-WL04 had 1,1-DCE (dichloroethene) at 28 ug/L and cis-1,2-DCE at 7,660 ug/L. Well 41755-WL05 had vinyl chloride at 21 ug/L. |
Louis Howard |
| 2/5/2007 |
Document, Report, or Work plan Review - other |
ADEC sent comment letter to 3 CES/CEVR re: Draft DP98 Treatability Study for Enhanced MNA dated December 2006. The text states Appendix A contains analytical laboratory results. The appendix does not contain any analytical laboratory results. Nor does it contain: chain of custody forms for each sample or group of samples, sample receipt forms, a case narrative, and a QA/QC summary/review.
The text states analytical data is available upon request from Parsons. In order to ensure consistency in data quality a technical memorandum (06-002 revised October 9, 2006) has been developed which summarizes the minimum requirements for both laboratory data packages and quality assurance (QA) Summaries (data reduction, verification, evaluation, etc.) that must be included in all reports containing analytical data submitted under the 18 AAC 75 and 18 AAC 78 regulations. The QA submittals described below are necessary to meet requirements of 18 AAC 75.335 (b) (2) (B) & (G), 75.335 (c) (3) & (4), 75.355 (a), 75.360 (2) and 18 AAC 78.007. While not being required for field work conducted in 2006, it is expected all future submittals to ADEC shall meet the minimum requirements for lab data packages/QA summaries and completed ADEC Laboratory Data Review Checklist(s).
The draft document did not include: 1) sample receipt forms documenting the condition of the samples, the ambient temperature of the shipping container adjacent to the sample containers (or temperature blank) WHEN RECEIVED by the laboratory; and; 2) a copy of the Chain of Custody(ies) (COC) for each sample or group of samples, including the COC for samples transferred to alternate locations. ADEC requests copies of these forms be submitted for review.
Please note that ADEC’s review and comments on this document are to ensure compliance with State of Alaska environmental conservation laws and regulations. While ADEC may comment on other state and federal laws and regulations, these comments do not relieve the Air Force, its contractors, subcontractors, or civilian personnel acting on its behalf, from the need to comply with other applicable laws and regulations. |
Louis Howard |
| 2/7/2007 |
Exposure Tracking Model Ranking |
|
Louis Howard |
| 4/2/2007 |
Update or Other Action |
Final Treatability Study report received for DP98.
The activities performed for this treatability study included installation of injection and monitoring wells, injection of a substrate mixture consisting of sodium lactate and emulsified vegetable oil, and four groundwater monitoring events. Specifically, these activities included the following:
• Installation of three substrate injection wells (DP98INJ-01 through DP98INJ-03) and three groundwater monitoring wells (DP98MW-04 through DP98MW-06) using hollow-stem auger (HSA) drilling methods in July 2005.
• Groundwater sampling of initial (i.e., pre-injection) conditions at each of the newly installed injection and monitoring wells, and existing well 41755-WL04, immediately preceding injection of substrate.
• Injection of approximately 2,275 gallons of an oil-in-water emulsion (containing vegetable oil and sodium lactate) and a water push of 1,030 gallons (containing sodium lactate) into the three injection wells in July 2005; and
• Performance (i.e., post-injection) groundwater monitoring at approximately 2, 10, and 14 months after injection (September 2005, May/June 2006, and September 2006).
The purpose of injecting soluble lactate was to ‘condition’ the aquifer for enhanced anaerobic biodegradation by rapidly reducing the mass of competing native electron acceptors and creating strongly anaerobic conditions within the treatment zone. The
purpose of injecting emulsified vegetable oil was to provide a source of slow-release substrate that would enhance and sustain anaerobic biodegradation of chlorinated ethenes in groundwater over a period of a year or more.
Recommendations: Data collected over 14 months following injection of substrate indicates that 1) site geochemistry has become more conducive to anaerobic degradation processes, 2)
biodegradation of TCE to cis-DCE has occurred, and 3) overall reductions in contaminant mass are limited in that the rate of degradation of cis-DCE is slow.
The current data are not of sufficient duration to determine if the treatability study will be capable of reaching all performance objectives and remediation goals. Substrate levels (measured as TOC) remain sufficient to sustain the reaction zone, and will likely
sustain highly anaerobic conditions for at least 12 more months. Data from this treatability study suggest that the period for acclimation and growth of dechlorinating microorganisms in a cold weather environment will be longer than observed for
applications in warmer environments in the lower 48 states. Therefore, Parsons recommends that the United States Air Force (USAF) continue to monitor the treatability study for an additional year to evaluate the full potential for enhanced bioremediation at
the DP98 Site.
Performance of additional monitoring events on an annual basis should be sufficient to determine the long-term impacts related to the injected substrate at DP98. The analyte list in the current sampling program could be reduced to those parameters most important in determining the effectiveness of the feasibility test system. For example, nitrate and phospholipid fatty acids (PLFA) could be eliminated from the sampling protocol. In addition, consideration should be given to using the DP98 site as a demonstration site for bioaugmentation to determine if degradation of cis-DCE to VC and ethene can be stimulated in a cold weather environment. |
Louis Howard |
| 4/17/2007 |
Update or Other Action |
RPO Report Draft received for Zone 1 Groundwater-DP98 was in Zone 1 (1 of 3 zones established for the Base as an effort by the Air Force to better manage sites). This report is an appendix to the 2006 Zone 1 Annual Basewide Field Activities Report (in progress) and contains groundwater monitoring data collected through the 2006 field season.
Originally 8 sites were managed under Zone 1: DP98, ST36/66, ST41, ST61, ST69, LF04 North, PL81, and WP14.
The list expanded to 11 sites that were managed under Zone 1: LF02, LF03, LF04, WP14, ST36/66, ST41, ST61, ST69, SS83, and DP98. LF02 is located in the southeastern portion of the base, near the Boniface gate, whereas the remaining ten sites are distributed throughout the northwestern portion of the base, between the airfield and Knik Arm. Groundwater contamination is tracked in 10 plumes at these sites, and exposed landfill debris is of concern at LF04.
The groundwater monitoring objectives for the DP98 Site are as follows: Reduce chlorinated COC concentrations in groundwater to DP98 ROD-specific cleanup levels. Verify that plume expansion is not occurring and that the monitoring network is sufficient for this purpose. Currently, the plume is monitored for all five of these chlorinated solvents. These COCs, their associated cleanup levels, and the model-predicted cleanup timelines (when available) are the monitoring components that are tracked to measure progress toward achieving monitoring objectives at the DP98 Plume.
If direct-push profiling is found to be impractical, possible DNAPL would be evaluated by two or three deep wells installed somewhat downgradient of the suspected source areas and screened from 10 feet below the water table to the bottom of the shallow aquifer (a screen length of approximately 50 feet). In these wells, contaminant concentration versus depth would be determined using passive diffusion bag (PDB) samplers suspended at 5- or 10-foot spacings along the screened interval.
Monitoring well 41755WL-08 increased from 1997 at 9.96 ug/L to 149 ug/L in 2006 which was the highest level of trichloroethene (TCE) recorded in this well. Well 41755WL-04: In 1999-TCE went from 5,000 mg/L to 620 mg/L in 2006. 1,1-DCE went from 9.4 ug/L in 1999 to 28.4 ug/L in 2006 and cis-1,2-DCE went from 2,200 ug/L to its highest level of 7,660 ug/L in 2006.
Well 41755WL-02: PCE went from 2,800 ug/L in 1999 to 1,240 ug/L in 2006. Cis-1,2-DCE went from 4,200 ug/L in 1999 to its highest level of 6,370 ug/L in 2006. Vinyl chloride went from 12.26 ug/L in 2000 to 21 ug/L in 2006.
Recommendations: Reduce sampling of upgradient well 41755WL-01 to once every five years. Increase sampling of downgradient wells:41755WL-15, 41755WL-16, and 41755WL-23 to once every two years. Include DRO and GRO in the analyte list for all wells in 2007. Develop a detailed physical conceptual site model for natural attenuation to explain recent observations of increasing contaminant concentrations. Conduct a detailed subsurface investigation to identify continuing sources of dissolved contamination. |
Louis Howard |
| 5/14/2007 |
Update or Other Action |
Draft 2006 Zone 1 Annual Remedial Process Optimization Report, April 2007 received on April 18, 2007. Based on the data presented in the report and any pending U.S. EPA comments, ADEC will approve the document as submitted. |
Louis Howard |
| 5/23/2007 |
Document, Report, or Work plan Review - other |
EPA comments on the Zone 1 RPO Report to Glen Verplancke 3 CES/CEVR Email message:
Great report. I agree with the changes to sampling frequency, fewer MNA parameters and water level measurements. Also the geometric regression may yield better predictions. I also think the use of the geoprobe for deep samples at DP 98 is a good idea.
This was a well written report, I especially like the site overview figure at the end. There are valuable observations made in this report , together with some changes to technique(PBDS), so it will be IMPORTANT for future work to revisit this info. I noted that at a couple sites they observed that we may need downgradient sentry wells to follow the plume, lets revisit that someday also.
Sorry I was late. Again, a very professional report. |
Louis Howard |
| 10/1/2007 |
Update or Other Action |
Final 2006 Zone 1 Field Activities Report received. 20 VOCs were detected in one or more of the sampled wells, & 1 VOC was detected in surface water. Among the VOCs detected in groundwater, only the 5 COCs & benzene exceeded cleanup levels. The highest COC concentrations (predominantly cis-1,2-DCE) occurred in 41755WL-02, -04, and -05, with lesser concentrations in -03. The highest concentrations exceeded cleanup levels by more than 2 orders of magnitude. Wells
41755WL-07 & -09 in the north-northwestern leading-edge area were ND for all VOCs.
Well 41755WL-08 in the northern leading-edge area was anomalous, contaminated mostly with TCE at more than an order of magnitude above the cleanup level but with no exceedances for the other COCs. These COC concentrations formed the basis of the plume outlines. Benzene, detected in several wells, exceeded the cleanup level only in 41755WL-01, the well farthest upgradient. The surface water sample (DP98SW-01) was ND for all VOCs except acetone, which was estimated to be present at a
level only slightly above the method detection limit (MDL).
A downward trend for PCE and TCE in 41755WL-02, noted previously (USAF 2006c), did not continue. Downward trends may be present for both TCE and cis-1,2-DCE in 41755WL-03 and for
TCE in -04. Upward trends may be present for cis-1,2-DCE in 41755WL-02 and -04 and for TCE in leading-edge well 41755WL-08. These trends show that PCE and TCE are probably degrading to cis-1,2-DCE in the main body of the plume but that cis-1,2-DCE appears to be stable. Data from 41755WL-01 hint that the upgradient edge of the plume may be attenuating, but at least one more round of sampling is needed to confirm this hypothesis. At
the leading edge (well 41755WL-08), TCE, along with a lesser concentration of cis-1,2-DCE, is migrating downgradient, causing the plume to expand slowly.
Conditions and trends in the DP98 plume are as follows:
• Upgradient—The trailing edge of the plume may be attenuating, but at least one more round of sampling from 41755WL-01 is needed.
• In plume—The body of the plume appears to be stable; PCE and TCE are probably degrading to cis-1,2-DCE, but cis-1,2-DCE appears to be stable and persistent.
• Downgradient—The leading edge of the plume may be migrating slowly but does not presently threaten surface water. Upward trends may be present for cis-1,2-DCE in 41755WL-02 and -04, and TCE in 41755WL-08.
When considering the site as a whole, MNA is clearly making little discernable progress toward cleanup. In-plume reducing conditions favor the slow transformation of PCE and TCE to cis-1,2-DCE, but little further degradation is occurring. In addition, the leading edge of the plume appears to be migrating slowly downgradient, resulting in increasing COC concentrations in 41755WL-08. The point-of-compliance kettle pond and associated bog lie about 400' farther downgradient but do not appear to be immediately (within 2 years) threatened by the migrating plume, given groundwater velocities of 46'/yr or less.
NOTE: Exceedances of 18 AAC 75 Table C values July 2006 results (cleanup level): 1,1-Dichloroethene 12.7 ug/L (7 ug/L) , |
Louis Howard |
| 11/20/2007 |
Update or Other Action |
Remedial Process Optimization (RPO) Report received. This report includes contaminated sites and the associated underlying groundwater for the western portion of Elmendorf Air Force Base
(AFB). This area, referred to as Zone 1, includes eight specific contaminated sites: DP98, ST36/66, ST41, ST61, ST69, LF04 North, PL81, and WP14. This report is an appendix to the 2006 Zone 1 Annual Basewide Field Activities Report (in progress) and contains groundwater monitoring data collected through the 2006 field season.
The eight Zone 1 sites were reviewed in accordance with the Remedial Process Optimization
Handbook (Air Force Center for Environmental Excellence [AFCEE] 2001). RPO is a systematic process for evaluating and improving site remediation so that maximum risk reduction is achieved for each dollar spent. RPO has three phases, which involve different levels of evaluation and effort. Phase I RPO involves a review of key performance data and progress toward site cleanup goals while ensuring remedy protectiveness. Phase II RPO involves a higher level of evaluation and effort and would be conducted only if the system were failing to achieve cleanup objectives or if there were an opportunity to pursue new cleanup goals. Phase III RPO involves implementation of RPO recommendations and depends on results of the first two phases.
The following recommendations are proposed for optimization of the remedial process at
DP98:
• Reduce the sampling frequency of upgradient well 41755WL-01 to once every five years.
• Increase the sampling frequency of downgradient wells 41755WL-15, 41755WL-16, and
41755WL-23 to once every two years.
• Measure groundwater levels in all site wells within a 48-hour period to provide a synoptic
view of the water table across a broader area than was measured in 2006.
• Measure groundwater levels in two site wells periodically over the course of the field
season to aid in interpreting the expected variability of groundwater analytical results.
• Include GRO and DRO in the analyte list for all wells in 2007.
• Conduct a detailed subsurface investigation to identify continuing sources of dissolved
contamination.
• Develop a detailed physical conceptual site model (CSM) for natural attenuation to
explain recent observations of increasing contaminant concentrations.
• Develop quantitative models of groundwater flow and contaminant fate and transport.
Inclusion of Gasoline-Range Organics and Diesel-Range Organics in the Analyte
List: For 2007, GRO and DRO will be added to the analyte list for all water samples. The fuel that is at this site is likely being used to drive reductive dechlorination of the chlorinated ethene COCs. The fuel contamination may also be inhibiting the movement of the chlorinated
COCs. An evaluation of the fuel concentrations at the site compared with historical data will
provide useful information for assessing MNA variables. Addition of these parameters is
consistent with the DP98 ROD (2004).
Revised Physical Conceptual Site Model: An updated physical CSM with greater detail is needed to account for the recently observed persistence and increases in dissolved contaminant concentrations. This CSM will incorporate the physical characteristics of chlorinated solvents and their subsurface distribution in conjunction with the subsurface geology of the DP98 site, the behavior of the groundwater system, and the biological and geochemical conditions in the subsurface.
|
Louis Howard |
| 4/28/2008 |
Document, Report, or Work plan Review - other |
Staff reviewed the Draft 2008 DP98 Evaluation/Compilation of Groundwater Data, April 2008. The text states gasoline range organics (GRO) and diesel range organics (DRO) are above action levels in soil and groundwater, but is not targeted for cleanup because it constitutes a minor risk to human health and aids in the remediation of the chlorinated ethenes. ADEC agrees, partially, with the statement. The 2004 Record of Decision for DP98 did not address the risk of petroleum hydrocarbons. Unless there was a risk assessment developed under 18 AAC 75 regulations and in accordance with ADEC’s Risk Assessment Procedure Manual, specifically for DRO and GRO which supports this statement, ADEC requests the Air Force remove reference to risk from petroleum hydrocarbons in this document.
The text states the best available in situ determinations of hydraulic conductivity come from unpublished slug tests conducted in three wells in 2004 (Table 3-2). ADEC requests the Air Force provide the documents containing these slug tests for review and its files.
The text states the diesel range organics (DRO) is also present and may become a contaminant of concern (COC) if significant concentrations remain at the conclusion of the monitored natural attenuation (MNA) remedy. The 2004 Record of Decision for DP98 (see Section 5.0 on Page 5-1) did not address risks or remediation of petroleum hydrocarbons and therefore, there is no standard listed in the ROD for “significant” petroleum hydrocarbons. ADEC requests the Air Force remove the reference to “significant” and state “...if concentrations remain above cleanup levels listed in 18 AAC 75.”
For future reference, at the end of the MNA remedy for DP98, when the chemical specific applicable or relevant and appropriate requirements (ARARs) are met as specified in the ROD, ADEC will require the Air Force to conduct additional characterization and possibly remediation for those contaminants detected above the most stringent cleanup levels listed in 18 AAC 75.341 Tables B1 and B2 for soil and 18 AAC 75.345 Table C for groundwater. Surface water and sediments will need to be addressed at that time as well for non-ROD COCs (e.g. TAH/TAqH, petroleum constituents, etc..) as required by 18 AAC 70 Water Quality Standards.
The text states no samples have been collected to assess whether significant COC concentrations occur in the surface water, volatilization and photodegradation may quickly attenuate any discharging contamination. The 2004 ROD at Section 12.2.2.1 on Page 12-4 states that surface water samples will be collected from the kettle pond annually as a point of compliance and sampled for the same sampling suite as the groundwater COCs.
Additionally, the 2004 ROD in Section 12.2.2.4 Duration/Termination of Monitored Natural Attenuation on Page 12-5 states surface water that is downgradient of the site and is believed to be in contact with the groundwater from the site will be monitored until such time all groundwater COCs meet chemical-specific ARARs. Surface water data has been collected and in the work plan for Figure 2-2 on Page 2-7 there is a listing of surface water sample results from 2005-2007 for chlorinated solvents and all were non-detect. ADEC requests the text be changed to reflect surface water sampling has been conducted, but the levels were non-detect. |
Louis Howard |
| 6/6/2008 |
Update or Other Action |
Air Force sent in the Draft Demonstration Plan for loading rates and impacts of substrate delivery for enhanced anaerobic bioremediation dated February 2, 2008 on June 5, 2008 for review.
The DP98 and Kenney Avenue Plume sites at Elmendorf AFB, Alaska have been selected for Phase II evaluations to determine whether incomplete dechlorination is a result of geochemical
conditions or microbiology. Dechlorination at the DP98 site stalled at cis-1,2-DCE after 15 months of monitoring, with some indications that an inability to induce low redox conditions may relate to the production of VC. Microcosm studies indicate that acclimation of dechlorinating bacteria proceeds very slowly in the cold groundwater at these sites. Therefore, soil (soil chemistry) and groundwater sampling (including molecular screening for
Dehalococcoides reductase genes) is proposed at the older DP98 site, while molecular only screening is proposed for the younger Kenney plume Avenue Site. Soils at the Kenney Avenue
Plume have been previously characterized in Fall 2007.
Only screening for Dehalococcoides reductase genes will be conducted at the Kenney Avenue Plume (four samples) since a rigorous biogeochemical sample protocol will be implemented there. Sampling at the Kenney Avenue Plume for a base monitoring event is scheduled for May 2008. Monitoring at the DP98 site is proposed for the same time to reduce mobilization and rental equipment costs.
Comments were in regards to an ADEC qualified person taking samples for the project and ensuring compliance with the ADEC technical memorandum for QA requirements as well as the Lab data review checklist. Comments were provided on soil sampling methods, however response to comments were that no soil sampling is being proposed for DP98 or Kenney Avenue Plume site under this field effort. Staff requested a map or figure be provided showing the sampling points proposed in the document. |
Louis Howard |
| 10/15/2008 |
Update or Other Action |
5 YR Review
Natural attenuation is the remedy for low concentration contaminants remaining at DP98 after the limited soil removal is completed. The Air Force will monitor the actual performance of the natural attenuation remedy in accordance with the following monitoring guidelines.
• Frequencies for GW & seep monitoring will be based on the sampling guidelines provided in the monitoring frequency decision guide from the DP98 ROD.
• Surface water samples will be collected from the kettle pond annually as a point of compliance & sampled for the same sampling suite as the GW COCs.
• The analytical testing of water samples will monitor concentrations of the COCs, daughter products, & other analytes, as appropriate. In addition, field-testing will monitor changes in site conditions. Analytes & field parameters will be measured to track changes in contaminant migration as well as to monitor the progress of natural attenuation.
• Natural attenuation in soil & sediment will not be monitored prior to collecting soil confirmation samples. Confirmation sampling will be conducted to confirm effectiveness of the natural attenuation of soil & sediment only after GW chemical-specific ARARs have been achieved.
After the first five years of GW monitoring, the Air Force will evaluate the progress of MNA. This evaluation will compile, analyze, & review all data collected, including information from the RI/FS, & the natural attenuation & treatability study remedy components described above. Additional GW modeling will be completed to provide updated estimates for the time frames to meet the cleanup goals.
Scheduled to be completed in October 2008.
After the ROD was signed in June 2004, there were several notable detections of contaminants at DP98 in addition to COCs:
• DRO, GRO, & benzene were detected at concentrations above the ADEC GW cleanup levels (ADEC, 2006d) &/or MCL. All of these contaminants are COPCs for DP98 & their detection does not indicate a new source of contamination. Monitoring for DRO & GRO was conducted at DP98 in 2007 (for first time since the ROD) to help assess the impact of petroleum hydrocarbons on natural attenuation of the chlorinated solvent COCs. Benzene was detected above the MCL of 5 µg/L at well 41755WL-01 (30.1 µg/L in 2006); however, concentrations are declining & this is the only well where benzene has been above the MCL. Benzene has consistently been a low-level contaminant at DP98, but it occurs at concentrations in excess of the MCL only at one isolated location.
• A few compounds were detected in GW samples for the first time since the ROD. The chlorinated solvent decay product 1,2-dichloroethane was detected in only one sample (0.58 µg/L) in 2006 & was only slightly above the detection limit for that sample. Methyl-ethyl-ketone (up to 5.3 µg/L) & methyl-isobutyl-ketone (up to 2.3 µg/L) were also detected. Ketones can be produced by fermentation of petroleum contaminants under low pH conditions, & are unstable in the environment. The MCL & ADEC cleanup standard for 1,2-dichloroethane is 5 µg/L, but standards have not been established for the ketones.
Recommendations for changes to the DP98 monitoring program include:
• Increase the sampling frequency of well 41755WL-08, located in the smaller COC plume, to semi-annual. The DP98 ROD (USAF, 2004d) requires this frequency of monitoring if wells are upgradient of a receptor & COC concentrations are increasing (Attachment F, Figure F-2).
• Sample surface water in the vicinity of well 41755WL-08 concurrently with GW
sampling.
Recommendations & Follow-up Actions
Increase the sampling frequency of well 41755WL-08, located in the smaller COC plume, to twice annually. The DP98 ROD requires this frequency of monitoring if wells are upgradient of a receptor & COC concentrations are increasing. Sample surface water in the vicinity of Well 41755WL-08 concurrently with GW samples.
Prepare a Remedial Action report when all components of the remedy are implemented.
The remedy at DP98 is expected to be protective of human health & the environment upon completion. In the interim, exposure pathways that could result in unacceptable risks are being controlled.
Future five-year reviews for OUs 1, 2, 4, 5 & 6 & DP98 are necessary because contamination remains above levels that allow for UU/UE in these areas. The next five-year review will be completed in 2013 & no later than five years from the signature date on this document.
|
Louis Howard |
| 3/17/2009 |
CERCLA ROD Periodic Review |
Cover letter to the EPA's Five-Year Review signature sheet sent to Richard J. Walberg, Colonel, US Air Force Vice-Commander from EPA Region 10 Office of Environmental Cleanup Daniel D. Opalski, Director. The Environmental Protection Agency (EPA) has completed their review of the third Five-Year Review report for the United States Air Force (USAF) Elmendorf Superfund site, in Anchorage Alaska.
EPA reviewed this report for technical adequacy, accuracy, and consistency with EPA guidance. In general, EPA agrees with the protectiveness determinations in this report. However, I understand that all parties to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 120 Federal Facility Agreement (FFA) are aware of a potential new source that has not been fully characterized, namely SS-022. It is also my understanding that while the Five-Year Review identifies this potential new source, the USAF has not adequately discussed the interim measures it has already taken to ensure protectiveness as site characterization proceeds, such as Institutional Controls (ICs) at SS-022 and the ongoing Remedial Investigation.
Therefore, we recommend that within ninety (90) days (by June 15, 2009), USAF supplement the Site File and Administrative Record with a Memorandum to document the ICs (e.g., installation of a fence, signage, and notation on the Environmental Restoration Program Atlas) that have been implemented for the protection of human health and the environment at SS-022. The Memorandum should also mention the Installation-wide ICs (including restriction of ground water use) already in place.
In addition, EPA agrees with USAF's recommendation for further action at the OU-l landfill area for the trichloroethylene (TCE) groundwater contamination, and requests that the Program Managers meet to discuss the timeline for completion of the groundwater contamination characterization and establish deadlines and, as appropriate, target dates for subtasks, as required under the FFA.
|
Louis Howard |
| 4/16/2009 |
Update or Other Action |
Staff reviewed and commented on the Draft Final 2009 Zone 1 Work Plan, Elmendorf Air Force Base, Alaska April 3, 2009. Zone 1 includes: LF02, LF04, WP14, ST36/66 (ST36 was associated with SERA Phase I and ST66 was associated with SERA Phase II), ST42, ST61, ST69 and DP98. DP98 Plume contains the contaminants of concern (C0Cs) = PCE, TCE, cis-DCE, 1,1-DCE, VC.
3.4.1 Sampling for Contaminants of Concern and Natural Attenuation Parameters Page 3-5: The text states: “In general, analytes are limited to the contaminants of concern (COCs) for each site, but five wells in the main plume at DP98 will also be sampled for methane and hydrogen as additional indicators of chemical reduction, complementing the redox estimates provided by measurements....”
ADEC requests the sample data for volatiles analysis (e.g. EPA Method SW8260B) list the results of all analytes detected by the method as well as the method detection limit (MDL), practical quantitation limit (PQL), concentrations, dilutions, data qualifiers, etc. in the appendix of the report.
The sample results for the COCs at a given site will be listed in the report in text and/or tables, but ADEC expects the Air Force to provide all the analytical results detected by the laboratory method. Because the Air Force is depending on natural attenuation of chlorinated solvents as its remedy, a discussion or graphical representation of these levels and the general trends of daughter products should be presented in the reporting document. This is especially important for vinyl chloride which is more toxic than the original contaminant of concern.
Appendix A Part I Table 6-2: The notes to the table for VOCs states the list of analytes requested for VOC analysis will be limited to COCs for the plume from which the water sample was taken. ADEC disagrees. ADEC requests the Air Force not limit the reporting of analytes to specific COCs, but have the laboratory report all of the compounds detected by the method in an appendix to the reporting document. This would be in addition to discussion in the report regarding the detected levels and general trends of expected daughter products from natural attenuation of the COCs.
Appendix A Part II: QAPP Table 3-1 4.2 Method Detection Limits, Reporting Limits, and Regulatory Criteria Page A-II-4-4: The table and text on this page refer to laboratory statement of work for each contaminant of concern. ADEC requests the Air Force not only report the COCs detected by each of the methods, but report all of the contaminants detected by the method in the appendix to the reporting document. This would be in addition to discussion in the report regarding the detected levels of expected daughter products generated as a part of the natural attenuation of the COCs.
|
Louis Howard |
| 12/1/2009 |
Update or Other Action |
Semi-Annual Progress Report received. SUMMARY OF WORK PERFORMED DURING LAST SIX MONTHS-Took groundwater samples at 10 monitoring wells and 1 surface water point of compliance (Jul 09), Conducted annual land use control (LUC) site inspection (Jul 09), Received the final DP98 Remedial Action Report (Sep 09) and Took 2nd round of groundwater samples at 1 monitoring well (Oct 09).
PLANNED ACTIVITIES FOR NEXT SIX MONTHS-Receive signature pages and distribute DP98 Remedial Action Report (Nov 09), Award FY10 Zone 1 Remedial Action-Operation (RA-O) project (Jan 10), Submit annual LUC report to EPA and ADEC (Jan 10), Receive work plan for demonstration project (Mar 10), Receive final 2009 Zone 1 Field Activities Report (May 10), Receive annual work plan for summer 2010 field activities (May 10), and Begin 2-year demonstration project - Biogeochemical Transformation versus Biogeochemical In-Situ Remediation (May 10) |
Louis Howard |
| 2/4/2010 |
Document, Report, or Work plan Review - other |
EPA (J. Gusmano) sent comments via email to USAF (D. Baumler) on the Draft Work Plan for Biogeochemical Transformation of Chlorinated Solvents for DP98. There is a very good overview of Anaerobic, Aerobic and Biogeochemical processes. However, the description of the Study Project begs a few questions from this reviewer.
The description of soil sampling at each cell is unclear. I believe you will be testing soils at two borings and, through a PID screen, will send one from each cell to a lab for VOCs analysis. But exactly where and how it will be collected is unclear.
The rationale for cell location in each plume is unclear. For example in Cell No.1, the location is not in an area of highest TCE, was the location random, or because of access issues?
In Cell No. 3 , EHC will be used. Is the fact that this plume is VC a consideration in the choice, or again was the choice random?
Finally, a major concern with any injection of this proportion, is the potential for flushing of contaminant down gradient. Selection of down gradient wells to measure this potential should be part of this effort.
A quick review of the Zone 1 Monitoring Plan leaves doubt as to a proper schedule or correct wells in current plans to detect such an event. If wells are too far from the cell it could take years to see the results, depending on GW flow rates. |
Louis Howard |
| 2/9/2010 |
Document, Report, or Work plan Review - other |
Staff reviewed & commented on the Draft Work Plan for Biogeochemical Transformation of Chlorinated Solvents at DP98, Elmendorf Air Force Base, Alaska January 2010. 1.6 Site-Specific Data Review Page 1-8: The text states that "Site-specific data were reviewed to evaluate GW flow & contaminant transport, & to evaluate locations for installation of the demonstration test cells at DP98." ADEC requests the Air Force provide clarification on how the location of the demonstration test cells was chosen by the contractor (e.g. random number generator, areas with the highest GW contamination or ease of access, etc).
3.1 DP98 Regulatory Requirements Page 3-2: ADEC requests the Air Force include those ARARs from the 2004 Record Of Decision for DP98 applicable to soil (Table 8-1 page 8-1) since this demonstration plan includes analysis for volatile organic compounds (VOCs) (See section 4.4.2 4th paragraph Page 4-10).
4.1 Technical Approach Page 4-1:The text states: "Up to four monitoring points will be installed for each test cell to allow monitoring of groundwater (GW) quality up gradient, within, & immediately downgradient of the reaction zone to evaluate the performance of each test cell." ADEC requests the Air Force consider sampling the existing monitoring GW wells at DP98 downgradient of the test cells on a more frequent basis for those wells on the biennial or five year monitoring schedule (e.g. annual monitoring frequency for the biennial wells & biennial monitoring frequency for the five year wells).
Absent the demonstration project's potential influence on GW velocity, the calculated horizontal GW velocity from the 2007 treatability study area is on the order of 6.3 feet per year (ft/yr) to 120 ft/yr (Treatability Study for Enhanced MNA at DP98, Section 2.2.3 Hydrogeology, April 2007 & 1.6.3 Page 1.9 of this demonstration plan). It appears the position of the GW monitoring points, installed 12 ft. downgradient from the demonstration test cells, may not account for average GW velocity at the site. This is especially true if one were to wait until 4 months after treatment as the initial monitoring event.
ADEC requests the Air Force either increase the distance for the downgradient monitoring point installation (e.g. 50 or 60 ft downgradient for Test Cells 2 & 3) or increase the monitoring frequency for GW (e.g. 3 months, 6 months, & 12 months after injection of amendments).
4.4.2 Borehole Advancement & Soil Sampling Page 4-10: The text states: "Soil samples will be collected from the two boreholes for monitoring points located within each test cell using an acetate-lined Geoprobe® core barrel within the 10-foot interval designated for injection of amendments. A portion of each sample will be used to measure the total ionizable volatile organic compound (VOC) concentration in soil headspace using a photoionization detector (PID)."
ADEC requests the Air Force provide further clarification on exactly how the soil samples will be field screened from the core barrel within the 10-foot interval & how that information will be used to guide soil sample collection. Unless otherwise approved by ADEC, all lab soil samples must be grab samples & may not be composited before analysis, except that soil samples for total arsenic, cadmium, chromium, & lead that are for screening purposes may be compo sited in the field or in the lab before analysis.
In accordance with 18 AAC 75.355 & 18 AAC 78.090, the Air Force shall ensure all soil sampling for this project will be conducted or directly supervised by personnel who meet the definition as defined by 18 AAC 75.990 (100) "qualified person". Soil samples for all parameters listed in UST Procedure Manual (adopted by reference by 18 AAC 75) Table 1: Reference Guide to Sample Collection & Lab Analysis, must be collected in accordance with method specifications.
4.5.1 GW & Soil Sampling Page 4-14:Soil samples will also be submitted to APPL, Inc. for analysis of VOCs (first sampling event) & to Microseeps for analysis of bulk iron & sulfide content (first & second sampling events). Samples from the second sampling event will also be provided to Camp Dresser & McKee for mineralogical analysis by scanning electron microprobe at the University of Colorado."
18 AAC 75.355 (e) states: Lab analysis under the site cleanup rules must be performed by a lab approved by the department under 18 AAC 78.800 - 18 AAC 78.815. The Air Force shall ensure that the labs used to conduct analyses for this demonstration project are certified for the methods & analytes described in this work plan when the analyses are scheduled to be performed. Please note according to the ADEC webpage http://www.dec.state.ak.us/eh/labIUSTLabs.aspx for "Labs Approved for Contaminated Sites Analysis Including Underground Storage Tank Sites", the APPL Clovis, CA lab's (UST-081) certification expires on June 17,2010. |
Louis Howard |
| 3/3/2010 |
Update or Other Action |
Zone 1 Field Activities Report received. Zone 1 is one of three zones established on EAFB for management of environmental restoration. Eight sites are managed under Zone 1: LF02, LF04, WP14, ST36/66, ST41, ST61, ST69, and DP98. Groundwater contamination is monitored at 10 plumes in Zone 1, and exposed landfill debris is removed annually at LF04. Five sites (LF02, LF04, WP14, ST41, and DP98) are administered under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) with U.S. Environmental Protection Agency (EPA) oversight and are governed by Records of Decision (ROD). The three remaining sites (ST36/66, ST61, and ST69) are regulated according to State of Alaska cleanup requirements.
The highest COC concentrations (predominantly cis-DCE) occurred in 41755WL-02, -04, -05, and DP98INJ-02, with lesser concentrations in 41755WL-03. In July 2009, the concentration of cis-DCE in 41755WL-08 exceeded its cleanup level for the first time. As in 2007, only one monitoring well (41755WL-01) contained measurable product.
Twenty temporary wellpoints were installed and sampled to investigate COC concentrations in two areas where natural attenuation may not be progressing. Concentrations of VC were ND except in DP98WP-0905, which was closest to the main body of the plume. GRO and DRO were detected in some wellpoints at less than cleanup levels (1,300 and 1,500 µg/L, respectively). The wellpoints delineated a lobe of TCE and cis-DCE contamination upgradient of monitoring well 41755WL-08. Although this lobe could be a continuous extension of the main body of the DP98 chlorinated solvent plumes, the absence of VC and the much lower levels of GRO and DRO indicate a different biogeochemical environment. To emphasize this, the updated plume outlines depict a separate zone of TCE contamination near 41755WL-08, consistent with the presence of TCE at only a low level in wellpoint DP98WP-0905.
Samples from 12 wellpoints in the area surrounding 41755WL-02 contained up to 78 µg/L PCE, 1,500 µg/L TCE, 2,100 µg/L cis-DCE, 110 µg/L 1/1-DCE, and 8.7 µg/L VC. In these samples, GRO ranged up to 3,800 µg/L and DRO ranged up to 250,000 µg/L. Although DRO concentrations greater than 3,000 to 5,000 µg/L generally indicate the presence of LNAPL, neither sheen nor product droplets were visible during sampling. However, the samples were very turbid, and suspended soil particles likely served as an emulsifying agent. The highest solvent concentrations were near monitoring well 41755WL-02 except for DP98WP-0915, which was located approximately 200 feet to the northwest and contained the highest TCE concentration (2,100 µg/L). Concentrations of cis-DCE generally followed a similar distribution pattern as TCE. VC results in wellpoints
surrounding 41755WL-02 ranged from ND to 8.7 µg/L and exceeded the cleanup level (2 µg/L) at six sample locations.
Recommendations for the future monitoring at DP98 include the following:
Collect the semiannual sample at monitoring well 41755WL-08 in May 2010 to confirm or refute the observed ND result for TCE in October 2009. If semiannual sampling of this well is required over the long term, May sampling would be preferable to October sampling because post-breakup hydrologic conditions most likely differ more from midsummer conditions than pre-freezeup conditions.
Collect two surface water samples in the vicinity of monitoring well 41755WL-08 in 2010 to investigate the relationship of the plume to the surface water. Samples should be collected one time during the regularly scheduled DP98 summer monitoring period (typically July). Samples should be collected at the DP98SW-03 location northwest of monitoring well 41755WL-08 and at a new location southwest of monitoring well 41755WL-08, as recommended in the 2007 RPO Report (USAF 2008b).
Install and sample a new monitoring well in the northern lobe, upgradient of 41755WL-08, to characterize attenuation in that portion of the plume. This well will target the core of combined TCE and cis-DCE contamination and should be located near wellpoint DP98WP-0904.
Predict a cleanup date for 41755WL-08 using a simple, one-dimensional fate-andtransport model (e.g., BIOCHLOR). This information may be useful for the next five-year review in 2012.
Evaluate whether the lack of attenuation in monitoring/injection well DP98INJ-02 warrants testing of further active measures (e.g., bioaugmentation with bacteria capable of metabolizing cis-DCE). Because this well is located in the core of the plume, its high COC concentrations are not threatening to enlarge the plume or discharge to the wetland. Therefore, continued monitoring of DP98INJ-02 may be most appropriate at this time. This evaluation may be completed before the next five-year review or as a result of the five-year review. |
Louis Howard |
| 4/28/2010 |
Update or Other Action |
Memorandum for ADEC. SUBJECT: Response to ADEC Comment on Draft 2009 Zone 1 Field Activities Report (Ref: ADEC Memo, 12.Mar 10)
1. This memorandum is in response to ADEC's concern as to why diesel-range organics (DRO) and gasoline-range organics (GRO) at select groundwater plumes were not sampled in 2009 as
previously agreed in a January 14, 2003 meeting. Specifically, ADEC's comment (Attachment 1) is in reference to Section 3.7.1 Implications of Contaminant and Geochemical Monitoring, Page 3-17 of the draft 2009 Zone 1 Field Activities Report, which stated: "The text states: When these parameters were monitored from 1999 to 2007, GRO concentrations in this monitoring well exceeded cleanup levels while DRO concentrations hovered near the cleanup level. ADEC requests the Air Force provide an explanation or a memorandum to the site file as an appendix to the document on why DRO and GRO were eliminated from the monitoring program as previously agreed to in a January 14, 2003 meeting with ADEC, USAF and EPA."
2. The analytes in question were not included in the Zone 1 groundwater monitoring program
for FY09 due to an administrative oversight. The agreement to monitor for DRO and GRO was
captured in meeting minutes (Attachlnent 2), not in a more formal mechanism such as a decision
document or memorandum to the·site file. In preparation for programming of project
requirements, we reviewed the governing documents for the Zone 1 sites. None of the governing
documents for Zone 1 sites identified GROIDRO as a contaminant ofconcem (COC); therefore,
GRO/DRO sampling was not programmed or conducted in 2009.
3. The U.S Air Force agrees with ADEC's request to continue sampling for diesel-range organics (DRO) and gasoline-range organics (GRO) for CERCLA sites with fuel-related plumes. Minutes of a 14 Jan 03 meeting with EPA, ADEC and DRS, provided with the above referenced ADEC memo, documents that the Air Force agreed to add DRO/GRO into the sampling program under the following conditions:
a. The decision will be documented in the 5-Year Review. The addition of DRO/GRO to the program should be introduced in the 5-Year Review under· mention of new issues affecting protectiveness.
b. The Air Force will NOT add DRO/GRO as a CERCLA ARAR, but will compare DRO/GRO results to ADEC cleanu levels in the annual re orts and will discuss in subsequent 5-Year Reviews. The benefit ofthis is that if CERCLA COCs meet ARARs, the Air Force can achieve a partial delisting.
c. The Air Force will add DRO and GRO to the suite of analyses at monitoring wells associated with fuel plumes starting in 2004.
d. The Air Force will not pursue a decision document with ADEC on DRO/GRO until more data is gathered on the extent of the problem.
e. Until a decision document is signed with ADEC, GRO and DRO concentrations will be compared to ADEC regulations in 18 AAC 75 (Table C, Groundwater Cleanup Levels; 1,500 ug/L for DRO, 1,300 ug/L GRO).
f. Sampling frequency for DRO/GRO will follow the latest Decision Guide for Sampling Frequency (see 2002 Basewide Annual Report). "Immediately up gradient" means within a 2-year warning line, similar to that generated for OU5.
g. ADEC GRO/DRO criteria apply to groundwater, not to seeps which daylight as surface water. Criteria in 18 AAC 70 (TAR, TAqH) apply to surface water.
4. The fact that these analytes were not included in the Zone 1 groundwater monitoring program
for FY09 is attributed to an oversight. The USAF will add DRO/GRO into the suite of analyses
at monitoring wells associated with fuel-related plumes for Zone 1 (LF04 South and WP14) and
will prepare a memo to the site file to prevent this type of oversight from occurring in the future.
The USAF strategy will be to compare DRO/GRO and total aromatic hydrocarbon (TAH)/total
aqueous hydrocarbon (TAqH) sample results as contaminants of interest with current ADEC
regulations in 18 AAC 75 - Table C - Groundwater Cleanup Levels and 18 AAC 70 for surface
water. Should you have any questions, please feel free to contact me at (907) 552-2875.
Signed Gary Fink YF-02 Chief, Environmental Restoration. |
Louis Howard |
| 11/17/2010 |
Meeting or Teleconference Held |
A meeting of the remedial project managers (RPMs) convened at 0900 on 17 November 10 at
the Joint Base Elmendorf-Richardson (JBER)-Richardson Conference Room in Building 658.
Attendees included: Mr. Bill Adams - Environmental Protection Agency (EPA); Mr. Louis
Howard - Alaska Department of Environmental Conservation (ADEC); Mr. Robert Shirley - Air
Force Center for Engineering and Environment (AFCEE) Western Region Environmental Office;
Mr. Nick Muszynski - AFCEE Restoration - Program Management Office (R-PMO); Mr. Rafael
Vazquez - AFCEE R-PMO; Mr. Jim Klasen - lith Air Force Environmental Attorney;
Ms. Renee Wright - Environmental Restoration Community Relations Coordinator; and CEANR
personnel - Mr. Gary Fink, Mr. Mark Prieksat, Ms. Donna Bawnler, Mr. Don Aide, Mr. Tim
Plucinski, Mr. Dick Nenahlo, and Ms. Cynthia Tomlinson.
DP98 Biogeochemical Transformation of Chlorinated Solvents Demonstration Project Status - Ms. Baumler explained the progress of this demonstration project, which is being conducted in an attempt to identify an enhanced approach to clean up chlorinated solvents in a cold groundwater environment. In May 2010, 3 test cells were injected with 3 different amendments. In Test Cell #1 EHC, a commercial product, mixed with makeup water was injected at 14 points at depths of 21-31' below ground surface (bgs); in Test Cell #2 emulsified vegetable oil (EVO) and powdered iron oxide (natural hematite) mixed with makeup water was injected at 11 points; and in Test Cell #3 EVa and ferrous sulfate mixed with makeup water was injected at 4 points at depths of 21-31' bgs.
The makeup water was primarily potable water from a City of Anchorage water supply with a limited quantity of groundwater from well development and purging. All injection points were abandoned (grouting with bentonite) and monitoring points were completed after injections with flush-mounted surface completions and locking caps. Two sampling events, a baseline was taken in May 2010 and the 1st round of samples (postinjection) were collected in September 2010 with two additional rounds scheduled for next summer (May and September). Sample results indicate that anaerobic degradation appears to have been stimulated; however, it is too soon to tell how much is due to sequential biotic dechlorination or abiotic degradation. Abiotic degradation is preferred as it does not produce regulated intermediate dechlorination products . |
Louis Howard |
| 1/28/2011 |
Update or Other Action |
Staff received the 2010 Annual Land Use Control (LUC) Monitoring Letter for DP98 and Operable
Units (OUs) 1,2,4,5, and 6. References: (a) DP98 Record of Decision, Section 12.2.3.4, dated May 2004, (b) OU6 Explanation of Significant Differences, Section 4.3.1.3, dated Mar 2007, and
(c) Memorandum to the Site File for OUs 1,2,4, and 5, Section 4, dated Jan 2010.
This letter serves as the annual monitoring report on the status of LUCs in place at DP98 and
at OUs 1,2,4,5 and 6.
Groundwater - The use of contaminated groundwater throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control or any other activity, is prohibited.
Soil - Excavating, digging, or drilling is restricted to reduce the possibility of migration
or exposure to contaminants that exceed chemical-specific applicable or relevant and appropriate requirements (ARARs). If contaminated soil that exceeds chemical-specific ARARs is excavated, it cannot be transported to or disposed of at another location on base. Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) waste. No dewatering of excavations or trenches will be allowed unless contaminated water is treated prior to use or disposal.
Any excavations or drilling greater than ten feet below ground 'surface will require
engineering controls to prevent downward migration of contamination and to protect the
groundwater aquifer.
The current land use will be maintained to reduce the possibility of exposure to
contaminants.
Evaluation - A land use control inspection was peiiol'med and land lise controls Qi'e in
place and continue to be effective at DP98. A demonstration project to stimulate
biogeochemical transformation and chemical reduction processes of chlorinated solvents began in 2010.
Three (3) test cells withfour (4) temporary monitoring points were constructed in May 2010. Each test cell was injected with an organic substrate and/or chemical amendment Baseline groundwater samples were taken in May and thefirst round of groundwater samples were collected in September 2010. Two (2) additional rounds of groundwater samples will be collected in 2011 and evaluated to determine if this cleanup technology for chlorinated solvents is effective in a cold weather environment.
The Air Force ensures compliance with LUCs by conducting periodic monitoring and completing site inspections. Separate controls are in place and enforced by the Air Force to prevent inappropriate soil and groundwater exposure at these sites. The Air Force currently requires all proj ects resulting in soil disturbance of greater than four inches below ground surface
to follow 3r Wing Instruction 32-1007, Safeguarding Utilities from Damage, dated 17 Aug 07
and 3rd Wing Instruction 32-7003, Land Use control Management, dated 16 Feb 07. Both instructions require the proponent to obtain an approved Base Civil Engineer Work Clearance
Request (3 WG Form 3) prior to conducting work on the Base. |
Louis Howard |
| 2/10/2011 |
Update or Other Action |
Zone 1 Draft Field Activities Report received. Results for field & MNA parameters identified two groups of wells, as in 2009:
The highest COC concentrations (predominantly cis-DCE) occurred in 41755WL-02, -03, & -05 with lesser concentrations in 41755WL-08 (Table 10-4). In 2009, the concentration of cis-DCE in 41755WL-08 exceeded its cleanup level for the first time. Concentrations this year appear similar to 2009 results.
Estimated cleanup dates for three of the five plume-core monitoring wells (41755WL-02, -03, & -05) are calculated according to the statistical geometric regression approach. As of 2009, the concentration trend in DP98INJ-02 had not yet shown a declining trend, preventing meaningful regression of data from that well. Two of the five plume-core monitoring wells (41755WL-04 & DP98INJ-02) were sampled by another contractor in 2010 & thus are not analyzed here.
Individual COCs in each well frequently have shown disparate trends. Analyzing trends by COC for each well produces a variety of results with no clear consensus regarding degradation rates or cleanup times. This situation may be simplified, however, by recognizing that cis-DCE (& 1,1-DCE) degradation is the limiting step (USAF 2008d). PCE & TCE concentrations can be considered to represent future cis-DCE levels. With the assumption that PCE & TCE degradation is faster than cis-DCE degradation, PCE & TCE concentrations can be added to cis-DCE (& 1,1-DCE) concentrations to obtain total COC values, reducing four COCs to one parameter. Before addition, PCE & TCE by-weight concentrations are scaled by the ratio of the formula weights of cis-DCE to PCE or TCE in order to conserve total molar concentrations. Although VC is the final step in the chain of chlorinated solvent degradation, its concentrations are least two orders of magnitude lower than cis-DCE.
Therefore, VC is expected to be below its cleanup level by the time cis-DCE reaches cleanup
& is not included in total COCs.
Estimated half-lives for attenuation of total COCs range from 7.0 to 9.4 years, with cleanup
predictions ranging from 2041 to 2073 (Figure 10-5a through c). These predictions are similar
to those reported in 2009 (2043 to 2078) & meet the ROD goal of cleanup in 75 years (by 2079). The data are moderately scattered, with correlation coefficients ranging from 0.45 to 0.85. The data sets for individual wells are also relatively small (seven to nine points), resulting in significant sensitivity to new data. Specific changes from 2009 to 2010 are as follows:
For monitoring well 41755WL-02 (Figure 10-5a), the cleanup date advanced from 2078 to 2073, & the correlation coefficient improved from 0.34 to 0.45.
For monitoring well 41755WL-03 (Figure 10-5b), the cleanup date advanced from 2043 to 2041, & the correlation coefficient improved from 0.39 to 0.48.
For monitoring well 41755WL-05 (Figure 10-5c), the cleanup date advanced from 2055 to 2049, & the correlation coefficient improved from 0.79 to 0.85.
Current understanding of the DP98 site confronts two problems:
The extent of contamination along the southwestern margin & at the upgradient edge of the northern lobe remains unbounded except by distant monitoring wells.
Duration of natural flushing of the northern lobe through monitoring well 41755WL-08 is unknown. The apparent stabilization of TCE & cis-DCE in this in well in 2010 offer hope that a downward trend may be established in several years, supporting prediction of a cleanup date.
Detection of TCE in the surface water near 41755WL-08 reiterates the need to understand the
contaminant dynamics upgradient of this well & the potential for additional contamination
surfacing in this area. Contaminants are not migrating to the downgradient point of
compliance nor to the next downgradient surface water point, but the extent, duration, &
potential for localized wildlife exposure due to plume discharge are unknown.
The 2010 recommendations for the future monitoring at DP98 include the following:
Continue the 2010 sampling program. Additional monitoring may be needed to support the 2010 treatability study, but those needs will be evaluated elsewhere.
Collect an additional round of samples from the two surface water locations (DP98SW-03 & -10) in the vicinity of monitoring well 41755WL-08 in 2011 to investigate further the relationship of the plume to surface water contamination & determine whether annual sampling would be beneficial. Protectiveness of the LUCs with respect to contaminated surface water should be evaluated in the next 5-year review in 2012.
Predict a cleanup date for 41755WL-08 using a simple, one-dimensional fate-andtransport
model (e.g., BIOCHLOR) & the upgradient distribution of contamination based on the 2009 temporary well point results. This information may be useful for the next 5-year review in 2012. |
Louis Howard |
| 2/24/2011 |
Document, Report, or Work plan Review - other |
Staff reviewed and approved the recommendations in the draft field activities report for this site. |
Louis Howard |
| 7/15/2011 |
Update or Other Action |
Draft Work Plan Environmental Remedial Action-Operations & LTM & Maintenance received.
The purpose of this project is to perform RA-O & LTM activities for several JBER Programs. These programs include sites distributed across both JBER-Elmendorf & JBER-Richardson. This Work Plan addresses remedial activities in JBER-Elmendorf Zone 1, Zone 2, & Zone 3 Management Areas, JBER-Elmendorf Compliance Restoration Program (CRP) sites, the JBER Elmendorf Operable Unit (OU) 1 Landfill, JBER-Richardson Multiple Installation Restoration Program (IRP) Sites, & JBER-Richardson Poleline Road & OUE Armored Vehicle Maintenance Area (AVMA).
Environmental Restoration Program Zone 1 Mgt Area covers the comparatively sparsely developed portions of JBER-Elmendorf to the west, north, & east of the airfield & administrative core of the base. Eleven sites are now managed under Zone 1: LF02, LF03, LF04, WP14, ST36/66, ST41, ST61, ST69, SS83, & DP98. LF02 & LF03 are located in the southeastern portion of the base, near the Boniface gate, whereas the remaining nine sites are distributed throughout the northwestern portion of the base, between the airfield & Knik Arm. GW contamination is tracked in nine plumes at these sites, & exposed landfill debris is of concern at LF04.
LF02, LF03, LF04, WP14, ST41, & DP98 are administered under CERCLA, with USEPA oversight, & are governed by ROD. The five remaining sites (ST36/66, ST61, ST69, & SS83) are regulated according to State of Alaska requirements. GW COCs for most of the sites (WP14, ST36/66, ST41, ST61, & SS83) are fuel constituents (one or more of benzene, toluene, ethylbenzene, xylenes, or diesel-range organics [DRO]). These sites were contaminated by pipeline & storage tank leaks & past practices. The primary sources have been removed, leaving secondary sources comprised of residual fuel distributed in contaminated smear zones at the water table. Two sites have chlorinated-solvent GW COCs: LF04 (1,2-dichloroethane & methylene chloride, as well as fuel constituents), & DP98 (chlorinated solvents). The chlorinated solvents occur in shallow GW as dissolved contaminants at LF04 & in conjunction with a DRO contaminated smear zone at DP98.
DP98 is a 27-acre site northwest of Buildings 18220 & 18224 on Fairchild Avenue. It includes a former vehicle maintenance building (Building 18224), two concrete buildings (Buildings 18218 & 18220), & a fan-shaped area of undeveloped land extending north & west of the perimeter fence. This site was known previously as ST423 under the SERA investigation of the USTs that serviced Building 18224.
At site DP98, the 381st Intelligence Squadron security will be notified whenever contractor & subcontractor personnel are onsite working outside the security fence. For work inside the fence, the contractor will arrange in advance for a security escort from the 381st Intelligence Squadron. Utility clearances are required for all soil disturbances within site DP98, which exceed a depth of 4 inches.
Seep & surface water samples include samples from LF02, LF04 South, ST41, & DP98. Seep & surface water samples will be submitted to a fixed-base laboratory for DRO, VOCs, & polynuclear aromatic hydrocarbon (PAH) analysis per Table 2.1. PAH & VOC concentration data will be used to calculate TAH & TAqH concentrations 117 to determine if results meet Alaska’s water quality standards presented in 18 AAC 70.
The Zone 1 Mgt Area sites are located throughout the western, northern, & eastern portions of JBER-Elmendorf. Nine sites on JBER are managed under Zone 1: LF02, LF04, WP14, ST36/66, ST41, ST69, SS83, & DP98. COC are tracked in all nine GW plumes at these sites, & are listed below. LF04 also contains an inactive landfill where debris is monitored & fallen debris removed.
• Site LF02 - 1,1,2,2-tetrachloroethane (PCA)
• Site LF04 - Benzene, ethylbenzene, toluene, methylene chloride, 1,2-dichloroethane
(DCA)
• Site WP14 - Benzene, ethylbenzene, toluene
• Site ST36/66 - diesel range organics (DRO)
• Site ST41 - benzene, toluene, ethylbenzene, & xylenes (BTEX)
• Site ST69 - Benzene
• Site SS83 - DRO
• Site DP98 - tetrachloroethene (PCE), Trichloroethene (TCE), 1,1-dichloroethene, cis-1,2-
dichloroethene, vinyl chloride (VC)
Zone 1 Management Area project objectives in 2011 include:
Evaluate & maintain the integrity of monitoring wells;
Evaluate GW flow characteristics while continuing to study trends in GW level with the monitoring wells; &
Evaluate erosion rates & characteristics of the LF04 bluff.
The activities to be performed under this TO include:
Collect & analyze GW & surface water samples;
Conduct GW level survey;
Perform maintenance of existing wells, as needed;
Install a maximum of 2 new/replacement GW wells;
Decommission a maximum of 5 damaged/redundant wells; &
Conduct LF04 erosion survey & debris removal. |
Louis Howard |
| 8/30/2011 |
Document, Report, or Work plan Review - other |
WP Addendum received and approved for field verification test of enhanced natural attenuation via email. |
Louis Howard |
| 2/2/2012 |
Update or Other Action |
Memorandum for 2010 Annual Land Use Control (LUC) Monitoring Letter for DP98 and OUs 1, 2, 4, 5, and 6 received by ADEC from 673 CES/CEANR.
References:
(a) DP98 Record of Decision, Section 12.2.3.4, dated May 2004
(b) OU6 Explanation of Significant Differences, Section 4.3.1.3, dated Mar 2007
(c) Memorandum to the Site File for OUs 1, 2, 4, and 5, Section 4, dated Jan 2010
1. This letter serves as the annual monitoring report on the status of LUCs in place at DP98 and at OUs 1, 2, 4, 5 and 6. The specific LUCs in place at each site are provided below. An evaluation of the implementation of these requirements is provided in bold following each specific LUC.
DP98: Groundwater - The use of contaminated groundwater throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control or any other activity, is prohibited.
Soil - Excavating, digging, or drilling is restricted to reduce the possibility of migration or exposure to contaminants that exceed chemical-specific applicable or relevant and appropriate requirements (ARARs). If contaminated soil that exceeds chemical-specific ARARs is excavated, it cannot be transported to or disposed of at another location on base.
Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) waste. No dewatering of excavations or trenches will be allowed unless contaminated water is treated prior to use or disposal.
Any excavations or drilling greater than ten feet below ground surface will require engineering controls to prevent downward migration of contamination and to protect the groundwater aquifer.
The current land use will be maintained to reduce the possibility of exposure to contaminants.
Evaluation - LUCs are in place and continue to be effective at DP98. A land use control inspection was accomplished in Oct 2011. The inspection forms will be presented in Appendix B of the 2011 Zones 1, 2, and 3 Mgt. Area Annual Report.
2. The Air Force ensures compliance with LUCs by conducting periodic monitoring and completing site inspections. Separate controls are in place and enforced by the Air Force to prevent inappropriate soil and groundwater exposure at these sites. The Air Force currently requires all projects resulting in soil disturbance of greater than four inches below ground surface to follow 3 Wing Instruction 32-1007, Safeguarding Utilities from Damage, dated 20 Aug 10 and 673d Wing Instruction 32-7003, Land Use control Management, dated 19 May 2011. Both instructions require the proponent to obtain an approved Base Civil Engineer Work Clearance Request (3 WG Form 3) prior to conducting work on the Base. |
Louis Howard |
| 3/16/2012 |
Update or Other Action |
Co-Occurrence of 1,4-Dioxane with Trichloroethylene in Chlorinated Solvent Groundwater Plumes at US Air Force Installations: Fact or Fiction
Richard H Anderson,*Janet K Anderson, and Paul A Bower
Air Force Center for Engineering and the Environment, Technical Support Division (AFCEE/TDV), 2261 Hughes, Site 155, Lackland AFB, Texas 78236, USA
Contractor, Air Force Center for Engineering and the Environment, Environmental Restoration Branch (AFCEE/ERD), Lackland AFB, Texas, USA (Submitted 22 November 2011; Returned for Revision 23 January 2012; Accepted 16 March 2012)
ABSTRACT
Increasing regulatory attention to 1,4-dioxane has prompted the United States Air Force (USAF) to evaluate potential environmental liabilities, primarily associated with legacy contamination, at an enterprise scale. Although accurately quantifying environmental liability is operationally dif?cult given limited historic environmental monitoring data, 1,4-dioxane is a known constituent (i.e., stabilizer) of chlorinated solvents, in particular 1,1,1-trichloroethane (TCA). Evidence regarding the co-occurrence of 1,4-dioxane and trichloroethylene (TCE), however, has been heavily debated.
In fact, the prevailing opinion is that 1,4-dioxane was not a constituent of past TCE formulations and, therefore, these 2 contaminants would not likely co-occur in the same groundwater plume. Because historic handling, storage, and disposal practices of chlorinated solvents have resulted in widespread groundwater contamination at USAF installations, signi?cant potential exists for unidenti?ed 1,4-dioxane contamination.
Therefore, the objective of this investigation is to determine the extent to which 1,4-dioxane co-occurs with TCE compared to TCA, and if these chemicals are co-contaminants, whether or not there is signi?cant correlation using available monitoring data. To accomplish these objectives, the USAF Environmental Restoration Program Information Management System (ERPIMS) was queried for all relevant records for groundwater monitoring wells (GMWs) with 1,4-dioxane, TCA, and TCE, on which both categorical and quantitative analyses were carried out.
Overall, ERPIMS contained 5788 GMWs from 49 installations with records for 1,4-dioxane, TCE, and TCA analytes. 1,4-Dioxane was observed in 17.4% of the GMWs with detections for TCE and/or TCA, which accounted for 93.7% of all 1,4-dioxane detections, verifying that 1,4-dioxane is seldom found independent of chlorinated solvent contamination. Surprisingly, 64.4% of all 1,4-dioxane detections were associated with TCE independently. Given the extensive data set, these results conclusively demonstrate for the ?rst time that 1,4-dioxane is a relatively common groundwater co-contaminant with TCE. Trend analysis demonstrated a positive log-linear relationship where median 1,4-dioxane levels increased between approximately 6% and approximately 20% of the increase in TCE levels.
In conclusion, this data mining exercise suggests that 1,4-dioxane has a probability of co-occurrence of approximately 17% with either TCE and/or TCA. Given the challenges imposed by remediation of 1,4-dioxane and the pending promulgation of a federal regulatory standard, environmental project managers should use the information presented in this article for prioritization of future characterization efforts to respond to the emerging issue. Importantly, site investigations should consider 1,4-dioxane a potential co-contaminant of TCE in groundwater plumes. Integr Environ Assess Manag 2012;8:731–737
|
Louis Howard |
| 4/10/2012 |
Update or Other Action |
Draft Annual Report for Zones 1, 2, and 3 received. Zone 1 consists of eleven sites: LF02, LF03, LF04, WP14, ST36/66, ST41, ST61, ST69, SS83, 723 and DP98.
Sheen was observed in three monitoring wells, DP98INJ-02, 41755WL-03, and 41755WL-05. Sheen has been observed historically in 41755WL-03. The highest COC levels (predominantly cis-DCE) occurred in 41755WL-2889 02, -04, -05, and DP98INJ-02, with lesser levels in 41755WL-03 and -08 (Table 2.43). In 2009, cis-DCE in 41755WL-08 exceeded its cleanup level for the first time. Levels this year appear similar to 2009 and 2010 results.
In 2011, several analytes with nondetect results had LODs that exceeded the cleanup levels. In
most cases, this was caused when the samples required dilutions at the laboratory during analysis due to high concentrations of other analytes in the sample. When the dilution factor was used to calculate the result, the LODs were then elevated to levels that were higher than normal.
Conditions and trends in the DP98 plume are as follows:
· Upgradient. COC concentrations in upgradient monitoring well 41755WL-01 have attenuated and are not expected to return, but DRO is expected to remain above the ADEC groundwater standard for some time. Last sampled in 2007, this well is scheduled 3047 for sampling every 5 years and was not monitored in 2011.
· In-plume. Concentration trends in most in-plume wells are consistent with degradation of
PCE and TCE to cis-DCE, but detection of VC (indicative of cis-DCE degradation) is limited to the center of the plume near wells 41755WL-03 and -05 and surrounding well 41755WL-02. VC increased in monitoring wells 41755WL-04 and DP98INJ-02 in 2011. Geometric regression of total COCs versus time for four in-plume wells (41755WL-02, -03, -04, and -05) predicted cleanup dates as far in the future as 2293, but the chlorinated solvents appear to be on track to attenuate by the target date of 2079.
Monitoring well 41755WL-08 may have reached a plateau for TCE and cis-DCE, indicating that natural flushing has advected the core of the plume to this well and that future concentrations
may decline, but at least one more year of semiannual monitoring is needed to bolster this
inference.
· Downgradient. The leading edges of the COC plumes appear stable. Sentry wells and the
surface water point of compliance were ND for all COCs.
Current understanding of the DP98 site confronts two problems:
· The extent of contamination along the southwestern margin and at the upgradient edge of
the northern lobe remains unbounded except by distant monitoring wells.
· Duration of natural flushing of the northern lobe through monitoring well 41755WL-08 is
unknown. Concentrations of TCE and cis-DCE in this well may be stabilizing, such that a
downward trend may be established in several years and support prediction of a cleanup
date.
The 2011 recommendations for the future monitoring at DP98 include the following:
· No changes to the sampling program presented in Table 2.41.
· Collect an additional round of samples from the two surface water locations (DP98SW-03 and -10) in the vicinity of monitoring well 41755WL-08 in 2012 to investigate further the relationship of the plume to surface water contamination and determine whether annual sampling would be beneficial.
· Evaluate protectiveness of the LUCs with respect to contaminated surface water in the
2012 five-year review.
Predict a cleanup date for 41755WL-08 using a simple, one-dimensional 3076 fate-and transport model (e.g., BIOCHLOR) and the upgradient distribution of contamination based on the 2009 temporary well point results.
|
Louis Howard |
| 3/1/2013 |
Institutional Control Update |
2012 Annual LUC IC Monitoring memorandum received. This letter serves as the annual monitoring report on the status of LUCs in place on JBER-Elmendorf at DP98 & OUs 1, 2, 4, 5 & 6. The specific LUCs in place at each site are provided below. An evaluation of the implementation of these requirements is provided in bold following each specific LUC.
DP98:
GW - The use of contaminated GW throughout DP98 for any purpose including, but not limited to, drinking, irrigation, fire control, dust control or any other activity, is prohibited.
Soil - Excavating, digging, or drilling is restricted to reduce the possibility of migration or exposure to contaminants that exceed chemical-specific applicable or relevant & appropriate requirements (ARARs). If contaminated soil that exceeds chemical-specific ARARs is excavated, it cannot be transported to or disposed of at another location on base. Excavated soil will be transported to a disposal facility in the lower 48 states, which is acceptable for disposal of Comprehensive Environmental Response, Compensation, & Liability Act (CERCLA) waste.
No dewatering of excavations or trenches will be allowed unless contaminated water is treated prior to use or disposal. Any excavations or drilling greater than ten feet below ground surface will require engineering controls to prevent downward migration of contamination & to protect the GW aquifer.
The current land use will be maintained to reduce the possibility of exposure to contaminants.
Evaluation -Inspection conducted on 29 Aug 12 & LUCs are in place & continue to be effective at DP98.
1. Soil borings to 5 ft. along the proposed path of fiber optic cables in OU4 East. The contractor submitted a SAP & sample results were below regulatory limits.
2. Soil borings to 5 ft. along the proposed path of fiber optic cables just within the northwestern boundary of SS22. The contractor submitted a SAP & sample results were below regulatory limits.
3. Replacement of water service on the eastern boundary of SS043. Dig site was not in the original area of contamination, but the excavator was informed of the potential to encounter contaminated soil. No contamination was encountered.
4. Electrical trenching to 4 feet deep north of building 16718 as part of ELM300 construction project within OU4 East. Trench line was within the area investigated during the ELM300 EECA, but the contractor was informed that there was a potential for contamination & that a PID should be used for screening. No contamination encountered.
5. Parking lot replacement near bldg. 10480. The excavator was informed that monitoring wells were in the area & that they must be protected.
6. Replacement of power line poles near LF03. The project was outside of the known boundaries of the site & LUC, but the contractor was informed that there was a possibility of encountering landfill waste. None was encountered.
7. Additional waterline work to #5 above. The same information was provided. We were informed that well 62WL-07 could not be located & that it was most likely destroyed during waterline work about 15 years ago. Unable to locate well casing.
8. Communication line work north of bldg. 27569. Contractor was informed of the location ofST36 boundary & what the requirements would be to trench through it & they chose to trench around it, but still screen for contamination with a PIO. No contamination was encountered.
9. Replacement of perimeter alann cable around 381- Communications facility (DP98). Approximately 25% of the linear distance would be within the DP98 LUC. Contractor submitted a SAP, performed field screening, & contaminated soil was not encountered. Dewatering was not necessary for this project since the excavation was only 30" deep & GW was not encountered.
10. Replace propane lines that were 1.5' deep north of bldg. 31562. Excavator was informed that there was a potential to encounter petroleum contamination due to the project's proximity to ST72. This work was not accomplished before the dig permit expired.
11. Capping of water line south of bldg. 5374. Excavator was infonned of the two sites in the area, ST76 & ST5 16, & the possibility of encountering petroleum soil contamination. The excavation took place outside of the known boundaries of both sites & no contamination was encountered.
12. Replace propane lines that were 1.5' deep north of bldg. 31562. Excavator was informed that there was a potential to encounter petroleum contamination due to the project's proximity to ST72. No contamination was encountered. |
Louis Howard |
| 5/30/2013 |
Update or Other Action |
Draft Annual Field Activities report received for review and comment.
This report summarizes the 2012 annual long-term management activities, including remedial
action-operation (RA-O) and Record of Decision (ROD) requirements conducted at Joint Base
Elmendorf-Richardson (JBER) Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) sites. The United States Air Force (USAF) has mandated a reduction
of long-term environmental liabilities and life-cycle costs through accelerated cleanup of
contaminated sites. As such, the Performance Based Remediation (PBR) initiative has been
developed to protect human health and the environment in a cost effective manner while at the
same time reducing life-cycle costs. In April 2012, Weston Solutions, Inc. (WESTON) was
awarded a PBR contract from the Air Force Civil Engineer Center (AFCEC) (Contract Number
FA8903-09-D-8589, Task Order No. 0016) that includes remediation and related activities at
several JBER contaminated sites. The contract includes performing RA-O and ROD
requirements at those sites. The WESTON Team performing the activities summarized in this
report consists of WESTON and CH2M Hill Constructors, Inc. (CH2M HILL). WESTON
executed project work on sites located within JBER-Elmendorf (JBER-E) while CH2M HILL
executed project work on sites located within JBER-Richardson (JBER-R).
This site was previously designated as ST423 under the State-Elmendorf Environmental Restoration Agreement (SERA) investigation of two underground storage tanks (USTs) that serviced Building 18224. In 1995, petroleum-hydrocarbon contamination was discovered in the
soil and groundwater during UST removal. During the 1997 SERA Phase VI investigation (USAF, 1998a), measurable concentrations of chlorinated solvents were confirmed in soil and groundwater samples, resulting in the addition of DP098 to the ERP in 1999 for further investigation.
In 2000, an engineering evaluation and cost analysis (USAF, 2001) delineated the chlorinated solvent contamination and characterized the site. In 2002, a remedial investigation/feasibility study (RI/FS) (USAF, 2003c) refined the nature and extent of contamination and reviewed data from previous investigations, determining that petroleum hydrocarbons and chlorinated solvents were present in the soil, sediment, and groundwater at DP098 at concentrations greater than cleanup levels.
Contamination at the DP098 site appears to originate from Building 18224 and two USTs located
on the southwest corner of the building that had been used to store diesel fuel. The tanks were
removed or abandoned in place in 1995 and are thought to have been the source of fuel
contamination at the site. Chlorinated solvents were most likely released from Building 18224
through floor drain tiles when it was used as a vehicle maintenance facility.
During 2012, groundwater monitoring wells were sampled for site COCs. Table 2-1 and Figure 2-1 presents a summary of analytical results. Surface-water sampling was not conducted. The point of compliance at the kettle pond (DP98SW-01) was not located and no surface water was observed in the surrounding area. Sampling was not required in 2012 for wells 41755WL-01 and 41577WL-23. A LUC inspection performed at DP098 on 29 August 2012 did not identify any LUC issues.
Site Summary
During 2012 activities groundwater samples were collected upgradient, downgradient and inplume.
The upgradient sample collected from monitoring well 41755WL-01 was analyzed for volatile organic compounds (VOCs) only. COC concentrations were below DP098 ROD cleanup criteria. This well is to be sampled again in 2017. The leading edges of the plume continue to appear stable. COCs in the downgradient wells were either non-detect or below DP098 ROD cleanup criteria. Concentration trends in the in-plume wells are consistent with historical results. 1,1-DCE concentrations decreased in DP98INJ-02; but overall, 2012 results indicated no notable changes.
Additional investigation to characterize soil and groundwater contamination is being proposed
for DP098 under the new PBR contract. No other changes to the annual monitoring are being
proposed for this site. |
Louis Howard |
| 6/3/2013 |
Document, Report, or Work plan Review - other |
Email from EPA Sandra Halstead (RPM) to JBER (Donna Baumler):
Donna, I did a quick skim of the 2012 annual report on Friday, and have a question that really needs to be clarified before I start on the review.
When we approved the 2012 Workplan addendum, it was based on the 2011 Field workplan QAPP (JBER Operations and LTM and Maintenance, Aug 2011).
In the 2012 Annual Report, Data Quality Assessment section, the report suggests the 2012 sampling used the Draft Basewide UFP (2012). I looked quickly at the Project Reporting Limits, and they differ for some compounds between the 2011 and Draft 2012 workplans. Also the 2011 Final workplan has a special table for the OU1 Landfill project cleanup limits, where the draft 2012 QAPP does not.
From the 2012 Annual Report, QA/QC Summary Report
Section 1.1 (this is the first place I found reference to the guiding workplan)
Acceptance criteria for this project are specified in the Draft Basewide Uniform Federal Policy-
Quality Assurance Project Plan (UFP-QAPP) (USAF, 2012b), criteria specified in the analytical
laboratory standard operating procedures (SOPs), and accepted analytical methods.
Please let us know if the annual report should be reviewed as sent. This may influence how non-detects are reported, and could influence other conclusions in the report. |
Louis Howard |
| 6/10/2013 |
Update or Other Action |
Draft 2012 Annual Report for CERCLA sites received.
Acceptance criteria for this project are specified in the Draft Basewide UFP-QAPP, criteria specified in the analytical lab SOPs, & accepted analytical methods. Overall, the data have met the quality control acceptance criteria specified for this project. Nonconformances of data are identified, discussed, & qualified in this report. When possible, direction of potential bias is assigned.
Surface-water sampling was not conducted. The point of compliance at the kettle pond (DP98SW-01) was not located & no surface water as observed in the surrounding area. Sampling was not required in 2012 for wells 41755WL-01 & 41577WL-23. A LUC inspection performed at DP098 on 29 August 2012 did not identify any LUC issues.
During 2012 activities groundwater samples were collected upgradient, downgradient & inplume. The upgradient sample collected from monitoring well 41755WL-01 was analyzed for VOCs only. COC concentrations were below DP098 ROD cleanup criteria. This well is to be sampled again in 2017. The leading edges of the plume continue to appear stable. COCs in the downgradient wells were either non-detect or below DP098 ROD cleanup criteria. Concentration trends in the in-plume wells are consistent with historical results.
Cis-1,2-DCE was highest in well DP98INJ-02 at 9,300 ug/L & in 41755WL-02 at 1,400 ug/L.
PCE 450 ug/L in 41755WL-02 (highest observed PCE & only exceedance of PCE).
TCE 570 ug/L in 41755WL-02 (highest obeserved TCE & 3 othere lower exceedances were observed).
Vinyl chloride in well DP98INJ-02 at 400 ug/L, & highest in two wells at 1,500 ug/L for well 41755WL-04 & 41755WL-04 (Field Duplicate).
1,1-DCE concentrations decreased in DP98INJ-02; but overall, 2012 results indicated no notable changes.
Benzene at 22 ug/L was in 41755WL-01
Additional investigation to characterize soil & groundwater contamination is being proposed under the new PBR contract. No other changes to the annual monitoring are being proposed for this site.
|
Louis Howard |
| 6/28/2013 |
Update or Other Action |
Staff provided review comments on the CERCLA Annual field activies report.
2.4 DP098 Site Summary
ADEC is requesting that 1,4-dioxane be sampled for in groundwater where trichloroethylene (TCE) or 1,1,1- trichloroethane (TCA) contamination exists or was previously above cleanup levels at any site (CERCLA or State restoration or compliance). Please incorporate these comments into any basewide sampling plans (current/future).
AFCEE research has found 1,4-dioxane at Air Force sites contaminated with TCE. The study, titled "Co-Occurrence of 1,4-Dioxane with Trichloroethylene in Chlorinated Solvent Groundwater Plumes at US Air Force Installations: Fact or Fiction," found detections of 1,4-dioxane at sites with TCE, independent of TCA.
"Surprisingly, 64.4% of all 1,4-dioxane detections were associated with TCE independently," the researchers say in the abstract. "Given the extensive data set, these results conclusively demonstrate for the first time that 1,4-dioxane is a relatively common groundwater co-contaminant with TCE."
The study authors recommend site investigations consider 1,4-dioxane as a potential co-contaminant of TCE at groundwater plume sites. The study, which was published in the Integrated Environmental Assessment and Management journal last year, explicitly warns that new discoveries of 1,4-dioxane contamination could delay cleanup completions and require more costly revisions to existing remedies, noting that there is strong evidence suggesting that 1,4-dioxane "will migrate much further than chlorinated solvents."
ADEC has promulgated enforceable cleanup levels (not advisories) for 1,4-Dioxane in soil and groundwater (latest version 18 AAC 75 April 2012 Table B1 and Table C) effective since 2008 which has remained unchanged in 2012 revised regulations.
Soil Under 40 inch Zone
540 mg/kg direct contact
0.21 mg/kg migration to groundwater
0.077 mg/L (77 µg/L) Table C groundwater cleanup level
This comment regarding monitoring requirements for 1,4-Dioxane applies to JBER-Elmendorf and JBER-Richardson sites with current or past TCE or TCA contamination. The monitoring requirement is also applicable to the “Early Warning and Sentry Wells” which were established to provide early detection of contaminant plumes that may impact Ship Creek or other downgradient environmental receptors.
1,4-Dioxane readily leaches to groundwater, is not expected to adsorb significantly to soil particles, and is difficult to biodegrade. Due to these properties, a 1,4-Dioxane plume typically proceeds ahead of the chlorinated solvent plume, and will tend to impact an aquifer system to a much larger extent.
Suggested laboratory methods: SW-846 Method 5030C, SW-846 Method 5021, SW-846 Method 8261A, SW-846 Method 5031, SW-846 8270C SIM, LVI and isotope dilution (1.0 µg/L or 2.0 µg/kg reporting limits). Dioxane can be detected using EPA 8260; however, its high water solubility causes relatively high reporting limits.
Routine organic extraction procedures like those traditionally used for EPA 8270 analyses produce low recoveries (approximately 50% or less). Whatever laboratory method is proposed for 1,4-Dioxane by JBER, the laboratory method must be able to detect at or below the ADEC promulgated groundwater cleanup level in Table C and migration to groundwater cleanup level in soil.
Be aware that with ADEC’s regulatory revisions in 2014, the level for 1,4-Dioxane (as well as many other compounds) will go down substantially from its current promulgated levels for soil and groundwater. These changes in regulations will be available for public comment sometime this year.
Finally, the EPA May 2013 Regional Screening Levels for tapwater lists a lower screening level of 0.67 ug/L which equates to a 1x10-6 total risk as well as a noncarcinogenic screening level of 47 µg/L which equates to a HI of 0.1.
|
Louis Howard |
| 8/2/2013 |
Update or Other Action |
Draft UFP-QAPP for DNAPL Evalution Work Plan received for review and comment.
The vertical and horizontal extent of CAH contamination at the site is unknown. Contaminant
distribution suggests the potential for a source below currently defined limits. The 2007 MIP
profiling indicated the potential for DNAPL at approximately 40 – 60 feet below ground surface
(bgs) and identified CAH contamination at depth presenting a potential data gap among the
existing evaluations and studies. A summary of the technical approach for the DNAPL
evaluation and data gap collection at this site is presented below.
Investigative Approach:
Three soil borings will be installed in the vicinity of the assumed drain tile (Figures 2 and 3). Soil borings 1 and 2 will be installed to a depth of 60 feet bgs and soil boring 3 will be installed to a depth of 70 feet bgs in order to better characterize the vertical limits of contamination. Three to four additional borings may be installed downgradient and perpendicular to the drain tile to better define the source. Field screening samples from the soil boring cores will be collected continuously along the core and screened utilizing a photoionization detector (PID). Based upon results of the PID field screening, one to two samples from each boring interval with the highest PID reading will be collected and submitted for laboratory analysis of gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), and volatile organic compounds (VOC) constituents.
In heavily contaminated locations, samples to be analyzed for polycyclic aromatic hydrocarbons (PAHs), extractable petroleum hydrocarbons (EPH), and volatile petroleum hydrocarbons (VPH) may also be collected. Sample preference will be given to depths below 30 feet bgs and/or at the soil water interface. The objective of these borings is to better define the potential source area and delineate the existing CAH plume. Figures 4 and 5 present cross-sections of known contamination at the DP98 site. |
Louis Howard |
| 8/19/2013 |
Update or Other Action |
Staff provided comments on the DNAPL Evaluation WP.
Table 15-1 & 15-2 Table 15-1 Comparison of TestAmerica-West Sacremento Laboratory DLs, LODs, & LOQs with DP98 Cleanup Levels for GW
The table lists a cleanup level for CAS No. 75-34-3 1,1-Dichloroethylene at 70 µg/L which is based on the 2004 Record of Decision based on 40 CFR141.61.
Be aware that the current 18 AAC 75 (April 8, 2013) regulations lists Table C GW cleanup level for 1,1-Dichloroethylene at 7 µg/L. While not a part of this PBR contract, this lower cleanup level for 1,1-Dichloroethylene in GW needs to be addressed at the next Five-Year Review. Changes in the promulgated standards or “to be considereds” (TBCs) may impact the protectiveness of the remedy. Similarly, JBER (as part of the review) should investigate the effect of significant changes in the risk parameters that were used to support the remedy selection, such as reference doses, cancer potency factors, & exposure pathways of concern. The toxicity data evaluation done in the original risk assessment should be reviewed to ensure that any assumptions made at the time of the original risk assessment continue to be protective.
For example, based on revised risk information for a specific chemical, a new standard (e.g., more stringent MCL for a chemical) may result in a situation where the cleanup level to be achieved by the original remedy would pose a 10-3 cancer risk. In that circumstance, the five-year review could recommend that a new cleanup level based on the new standard be adopted &, if necessary, that the remedy be modified. However, a change in a standard may not necessarily result in a change in the resulting risk & therefore may not always impact protectiveness .
Table 15-2 Comparison of TestAmerica-West Sacramento Laboratory DLs, LODs, & LOQs with DP98 ROD Cleanup levels
The table lists a cleanup level for CAS No. 156-59-2 cis-1,2-Dichloroethylene at 0.2 mg/kg which is based on the 2004 Record of Decision. Be aware that the current 18 AAC 75 (April 8, 2012) regulations has a higher migration to GW cleanup level of 0.24 mg/kg..
The table lists a cleanup level for CAS No. 127-18-4 Tetrachloroethylene at 0.03 mg/kg which is based on the 2004 Record of Decision. Be aware that the current 18 AAC 75 (April 8, 2012) regulations has a lower migration to GW cleanup level of 0.024 mg/kg.
The table lists a cleanup level for CAS No. 79-01-6 Trichloroethylene at 0.027 mg/kg which is based on the 2004 Record of Decision. Be aware that the current 18 AAC 75 (April 8, 2012) regulations has a lower migration to GW cleanup level of 0.020 mg/kg.
While not a part of the scope of the PBR contract for this site, see comment above regarding lower soil cleanup levels & the Five-Year Review.
Please be aware, as of July 2, 2013, based on email correspondence from EPA on another CERCLA site with VOC contamination, EPA no longer recommends the sodium bisulfate preservative for SW8260 low-level analysis of VOCs; instead EPA recommends JBER use VOC/VOA vials with a water carrier. These samples will be in addition to the methanol-preserved SW8260 samples required by ADEC. Therefore, both methanol-preserved VOC soil samples & VOC/VOA vials with a water carrier will be required for CERCLA site DP098. An addendum to the Final approved Basewide UFP-QAPP &/or method specific exception eliminating sodium bisulfate preservation for “low-level” VOC soil analysis noted in this site-specific UFP-QAPP will be required.
WS #10 Sampling Design & Rationale
Site-Specific Sampling Plan
Soil & Sampling
ADEC appreciates that JBER is sampling for petroleum hydrocarbons at this site for future historical reference & remedial action after such time in the future when the ROD soil COC cleanup levels are met under State regulations (18 AAC 75/18 AAC 78). ADEC requests what the petroleum data will be used for (if at all under this project) & how collecting it will meet the objectives of the DNAPL evaluation at DP098.
Fuel hydrocarbons are above cleanup levels at DP098 but were not identified as official COCs in the ROD. |
Louis Howard |
| 9/6/2013 |
Document, Report, or Work plan Review - other |
EPA provided comments on the DNAPL evaluation WP.
The Draft QAPP alludes to work conducted on the site after 2009 ( Table 1-1, W #10 Data Gaps, References) but does not provide any reference or the results of these past investigations. Please incorporate the major components & lessons learned from earlier treatability investigations & monitoring into this workplan. In particular, the DP98 Biogeochemical Transformation Technology Demonstration Report, dated 3/29/12, appears to have crucial & relevant information to contribute to this DNAPL evaluation workplan.
Comment: The text states: “three soil borings will be installed in the vicinity of the assumed drain tile” to 60 & 70’ bgs & “three to four additional borings may be installed downgradient & perpendicular to the drain tile,” but does not provide decision criteria for determining how many of the additional borings will be installed or how deep the additional borings will be.
Please revise to include decision criteria for determining how many of the additional borings will be installed or how deep the additional borings will be.
Comment: The text states “based upon results of the PID [photoionization detector ] field screening, one to two samples from each boring interval with the highest PID reading will be collected,” but does not indicate the length of a boring interval (1 foot, 5 feet, etc.).
In addition, the text does not describe in what instances two samples will be collected from an interval instead of one (duplicate samples, higher PID readings, etc.).
Also, the text indicates that “in heavily contaminated locations, samples to be analyzed for polycyclic aromatic hydrocarbons (PAHs), extractable petroleum hydrocarbons (EPH), & volatile petroleum hydrocarbons (VPH) may also be collected;” however, the Draft QAPP does not define what qualifies as “heavily contaminated” & does not provide decision criteria for determining when samples for these additional analyses will be collected.
Lastly, the text indicates that “sample preference will be given to depths below 30 feet bgs &/or at the soil/water interface;” however, chlorinated aliphatic hydrocarbons (CAHs) diffuse into fine-grained units, so for detection of maximum CAH concentrations, samples should be collected from the top of fine-grained units.
Please revise the text to specify the length of a boring interval & to describe in what instances two samples will be collected instead of one from an interval. Please also revise the text to define “heavily contaminated” & to include decision criteria for determining when samples for the additional analyses (PAHs, EPH, & VPH) will be collected. Lastly, please consider sampling the top of fine-grained units in order to find maximum CAH concentrations.
Comment: The Draft QAPP does not consistently present the source of contaminants at the site. For example, page ES-1 of the Executive Summary states “Release of these contaminants is attributed to historic maintenance & cleaning operations conducted in Building 18224. The CAHs are interpreted to have been discharged to the floor drains of Building 18224, which subsequently discharged to a drainage system northwest of the building,” while Worksheet #10 states “the contamination at DP98 is a result of releases of petroleum hydrocarbons from former underground storage tanks (USTs) that serviced Building 18224 & releases of chlorinated solvents from the floor drains of Building 18224.” Figure 6 lists concrete pads as the contaminant source. Please revise the text to consistently present the source(s) of contaminants at DP98.
Comment: The Draft QAPP does not display the locations of Membrane Interface Probe (MIP) borings installed during the 2007 MIP Investigation. Please revise the figures to show the locations of MIP borings.
Figure 4
Page ES-11 Comment: Boring 41755WL04 on Figure 4 shows a concentration of 196 (units not provided) in blue, indicating this is an uncontaminated saturated zone result; however, the interval just above this sample had a concentration of 83.8 (units not provided) in red, indicating this is contaminated saturated zone. It is not clear why the higher concentration is also not depicted in red. Please resolve this discrepancy.
|
Louis Howard |
| 9/16/2013 |
Document, Report, or Work plan Review - other |
Draft 2 CERCLA Annual Monitoring report received for review and comment.
2.4 Page 2-2
Not addressed in revised draft version 2 dated August 2013, but still an ADEC concern for JBER-E and JBER-E where TCE and/or TCA contamination exists or was previously above cleanup levels in groundwater. While outside the scope of the PBR contract that is scheduled to the year 2020, ADEC expects JBER to address this State promulgated contaminant in the future. Comment is not withdrawn by ADEC.
The Air Force is the responsible party under State and Federal statutes on JBER-E and JBER-R despite the fact that the April 2012 Contractor’s Statement of Objectives (SOO) relieves the Contractor (but not the Air Force) of certain requirements.
The SOO states: “The Contractor shall not be responsible for:
2. Remediation or treatment of emerging contaminants.
3. Regulatory changes (e.g. reduction in maximum contaminant level (MCL).”
3.4 Page 3-2
Comment not addressed in revised draft version 2 dated August 2013, but still an ADEC concern. While outside the scope of the PBR contract that is scheduled to the year 2020, ADEC expects JBER to address this issue regarding PFCs in the future.
In accordance with 18 AAC 75.340 (g) , ADEC has developed cleanup levels for PFOS and PFOA.
The Air Force is the responsible party under State and Federal statutes on JBER-E and JBER-R despite the fact that the April 2012 Contractor’s Statement of Objectives (SOO) relieves the Contractor (but not the Air Force) of certain requirements.
The SOO states: “The Contractor shall not be responsible for:
2. Remediation or treatment of emerging contaminants.
3. Regulatory changes (e.g. reduction in maximum contaminant level (MCL).”
Comment is not withdrawn by ADEC.
|
Louis Howard |
| 9/16/2013 |
Update or Other Action |
Biogeochemical Transformation Tech Demonstration report under Contract No. FA8903-08-D-8778, Task Order 0068 received.
The overall objective for the technology demonstration was to evaluate the extent to which biogeochemical transformation or other in situ chemical reduction (ISCR) techniques may be used to reduce concentrations of CAHs within test cell treatment zones to levels protective of human health & the environment. Performance metrics developed for the demonstration included the following:
Stimulate the production of reduced iron sulfides (measured as acid volatile sulfide [AVS]) to concentrations equal to or greater than 2,000 mg/kg within 2 in situ treatment zones (test cells);
Enhance the rates of in situ anaerobic degradation of PCE & TCE by 1 order of magnitude or more relative to rates of natural attenuation at the site;
Reduce concentrations of PCE & TCE in the treatment zones to less than site-specific cleanup goals, & limit increases in DCE & VC to concentrations measured during base-line monitoring or to concentrations measured in upgradient monitoring locations &
Reduce total molar concentrations of chloroethenes within the treatment zones by 90 percent or more to demonstrate that complete transformation is occurring, & not just transformation of highly-chlorinated ethenes (PCE & TCE) to less-chlorinated ethenes (DCE & VC).
Engineered biogeochemical transformation shows promise for remediation of chlorinated solvents in GW, particularly for sites with chlorinated ethenes where sequential biotic dechlorination stalls at DCE or VC.
The most promising results were observed at Test Cell No. 2, where a combination of natural hematite iron powder, calcium sulfate, & a buffered EVO product were injected. While an increase in concentrations of iron sulfides in soil were not observed, the degradation pattern for shows a strong abiotic signature. The greatest reductions in concentrations of chlorinated ethenes occurred after the 3.5-month soil sampling event.
Therefore, it is possible that the post-injection soil measurements are not representative of the extent to which biogeochemical transformation of TCE & DCE occurred over the duration of the demonstration.
Results for Test Cell No. 1 (EHC®) & Test Cell No. 3 (soluble ferrous sulfate & buffered EVO) indicated that sequential biotic dechlorination occurred, with a significant accumulation of VC. This may be due to the much higher concentrations of DOC in these two test cells, which may have preferentially stimulated biotic dechlorination relative to abiotic dechlorination by biogeochemical transformation. Ethene was produced, indicating the potential for sequential biotic dechlorination to go to completion. However, the relatively slow rate of VC transformation to ethene raises concern whether biotic processes alone can be an effective remedy.
The results of the SEM evaluation & mineral speciation analyses suggest that any reduced iron sulfide minerals that were produced were oxidized to more stable, less reactive forms of pyrite. The rate at which biogeochemical processes produce iron sulfide minerals from the amendments used is not well understood. The presence of hematite grains in Test Cell No. 2 at 3.5 months post-injection suggests the process was ongoing, with the potential for greater concentrations of iron sulfide to be produced over time. The rate of dechlorination of TCE & DCE at Test Cell No. 2 increased after the 3.5-month post-injection soil sampling event.
Therefore, the concentrations of AVS & CRS measured may not be representative of the degree to which the formation of iron sulfide minerals was ultimately achieved. |
Louis Howard |
| 11/4/2013 |
Update or Other Action |
Fourth Five-Year Review (draft) received for review & comment.
The remedy at DP98 has been implemented & continues to operate & function as designed. Although TCE is detected in surface water collected near 41755WL-08, contaminant concentrations at the ROD-specified point of compliance consistently meet requirements. In general, the monitoring program data indicates that DP98 contaminants are naturally attenuating. However, the rate at which the COCs are naturally attenuating at each well is variable. GW data were compiled to assist in the evaluation of the MNA remedy. The COC plume appears to be stable & is not likely to expand beyond the LUC boundary. All components of the ROD-specified remedy have been implemented.
Analytes retained as groundwater (GW), sediment, soil, or surface water COPCs in the ROD were compared to current cleanup levels. A new ADEC cleanup standard &/or MCLs (not addressed in the ROD or previous Five-Year Reviews) had been promulgated for one GW COPC (chloromethane) (Appendix B, Table B-1). However, the maximum concentration of chloromethane detected at the site at the time of the ROD was below the newly promulgated cleanup level; therefore, the newly promulgated cleanup level does not call into question the protectiveness of the remedy.
The assessment of potential vapor intrusion risk to indoor air has evolved significantly during the review period; requiring multiple lines of evidence to support assessment findings. A manned facility is located in close proximity to the DP98 GW plume. Historic vapor intrusion assessments have occurred at DP98; however, additional lines of evidence are needed to support short- & long-term protectiveness.
Changes to DP98 COC chemical-specific toxicity information that occurred since the 2008 Five-Year Review affect three of the COCs, cis-1,2-DCE, TCE, & PCE. The ROD-established groundwater RAOs were assessed for protectiveness by applying the updated chemical-specific toxicity information & calculating the hazard quotient & cancer risk at the RAO concentration. The ADEC Risk Procedures Manual (ADEC, 2000) was followed for the assessment. The assessment found that the GW RAOs continue to be protective of human health under a residential exposure assumption.
The vapor intrusion pathway was considered in the risk assessment that supported the DP98 ROD. However, results from the vapor intrusion sampling were not available at the time of this review. TCE vapor intrusion risk at DP98 should be re-evaluated using the current toxicity information, which has been updated since 2008.
The MNA remedy is progressing slowly, particularly the attenuation of vinyl chloride. An accurate cleanup date for the site cannot be reasonably predicted at this time. However, it does not appear that the 35- to 75-year remedy timeframe identified in the ROD will be achieved.
Issues: Indoor air sampling at DP98 appears to indicate that no unacceptable risk is occurring. However, the historical efforts do not meet the current standard of multiple lines of evidence.
The timeframe to meet the RAOs is 35 to 75 years. The current monitoring data appears to indicate that the remedy timeframe may not be possible using only natural attenuation.
Protectiveness: Protectiveness determination of the remedy at DP98 is deferred until the potential impacts associated with the vapor intrusion pathway at the site are evaluated. The vapor intrusion assessment is expected to be performed in 2014.
The Future Five-Year Reviews for OUs 1, 2, 4, 5 & 6 & Site DP98 are necessary because contamination remains above levels that allow for UU/UE in these areas. The next Five-Year Review is due on or before January 27, 2019.
|
Louis Howard |
| 12/20/2013 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft 4th 5 Year Review report.
7.6 DP98
Question B: Are the exposure assumption, toxicity data, cleanup levels and RAOs used at the time of the remedy selection still valid?
Answer: Yes
Changes in Standards and TBCs
This is partially correct for sources with trichloroethylene (TCE) groundwater contamination. See comment #6 above regarding 1,4-Dioxane cleanup levels and sampling requirements. TCE was identified as a contaminant present in water most likely present due to past disposal practices at DP98.
Page 7-25 Changes in Toxicity and Other Contaminant Characteristics DP98 - The text states: “The ROD-established groundwater RAOs were assessed for protectiveness by applying the updated chemical-specific toxicity information and calculating the hazard quotient and cancer risk at the RAO concentration.”
Please reference the sources for the updated chemical-specific toxicity information for the DP98 COCs.
9.0 Table 9-1 OU4, OU5, DP-98 - There is no description here or in the text of the document on the exact number of occupied facilities or manned facilities that are in proximity to VOC groundwater plumes or potential affected by the TCE plumes. A general idea of the number of facilities will help determine the scope of the vapor intrusion assessment required at each of these facilities before 12/31/2016. ADEC requests either here or in the text of the document a description be added detailing the number of facilities expected to be assessed. OU6 SD15 and OU1 need to be added to the table if there are manned/occupied facilities present in proximity to the TCE plume at LF059 and SD15.
|
Louis Howard |
| 1/3/2014 |
Document, Report, or Work plan Review - other |
EPA comments on the draft 4th 5 Year Review report.
Comment: The content in the tables in Section 8 Issues & Section 9 Recommendations & Followup Actions should be carried into the Summary Form Issues & Recommendations accordingly. The Summary Form will be the part of the Five Year Review that will reviewed most frequently & should contain enough detail to clearly outline the issues, recommendations, & actions to be tracked.
The document includes details in Section 8 but not in the Summary Form or vice versa.
Examples include DP98, Table 8-1 which describes “the timeline for meeting RAOs is 35-75 years, & the current monitoring data indicates the remedy timeframe may not be possible using only natural attenuation”. The Summary Form describes the DP98 Remedy Performance issue as “Historical Data indicate no decreasing trend for COCs in the GW. It is not possible to predict a cleanup date for the DP98 site”. The Summary form should outline the issue as “natural attenuation alone may not achieve RAOs within the 35-75 year timeline as specified in the ROD”.
Please amend the Issues & Recommendations/Follow-up Actions, in both the Summary form & Sections 8 & 9, to include specific chemicals of concern, remedial timeframes, or actions to be taken with enough detail to allow the Summary Form to function as nearly a stand-alone document.
Summary Form pages S-2 to S-5 Comment: For the deferred protectiveness on OU4, OU5, & DP98 , it is recommended to change the current protectiveness to “No” & to establish an interim milestone date in 2014 for assessment of vapor intrusion risk in occupied residences & offices.
If data currently exists that suggests this is a current protectiveness issue & complete pathway, then the answer can be retained as ‘yes’. Section 6.4 Data Review did not present vapor intrusion data, calculations, or assessment to be able to answer this question.
Summary Form OU4, OU5, DP98 Monitoring VI pathway Pages S-3, S-4, S-5 Comment: EPA agrees with both the issue of potential vapor intrusion & evaluation of the VI risk in these OUs, however the recommendation should spell out what is intended in the “vapor intrusion evaluations that provide multiple lines of evidence” as outlined in OU4 & DP98. OU5 recommends a “comprehensive vapor intrusion study, especially in terms of residential occupancy exposure”.
Page 8 of Assessing Protectiveness at Sites for VI - 5YR Supplemental Guidance (OSWER Directive 9200.2-84) provides additional direction for the data collection efforts. The magnitude & extent of the VI investigation is not defined (how VI will be characterized, estimate how many buildings will be assessed).
Additionally, the current monitoring well networks at many sites do not appear adequate to define the extent of GW plumes or determine whether plumes remain stable. This affects not only the MNA effectiveness determination but may also hinder the vapor intrusion assessments attributed to VOC plumes.
It is suggested to prioritize the vapor intrusion evaluations at these OUs. Select interim milestones for conducting the vapor assessments by the end of calendar year 2014 & identify 2016 as the date the protectiveness determination can be made
1) Prioritize evaluation of residential indoor air VOC concentrations, followed by office spaces
2) The plume source & boundaries for the OU5 plumes are not well defined, & any VI evaluation at this OU should concentrate on residential housing & office space in & around the OU5 plumes as a priority.
Summary Form DP98 Remedy Performance Page S-5 Comment: Table 8-1 provides a more detailed description of the issue (see Comment #3 above, example DP98).
The recommendation of “increasing the scale of the pilot tests to improve remedial performance” is problematic. If pilot tests have identified an alternative remedy that shows promise at reducing GW COC concentrations, the recommendation should be to “implement the alternative remedy” through the CERCLA process.
|
Louis Howard |
| 3/17/2014 |
Document, Report, or Work plan Review - other |
EPA Letter to Air Force regarding the 4th Five Year Review for JBER-Elmendorf.
DP98
The EPA concurs with the deferred protectiveness determination for DP98 pending additional sampling to address the potential for vapor intrusion at occupied buildings in proximity to the contaminated chlorinated GW plumes. The vapor intrusion (VI) evaluation will prioritize buildings with the most vulnerable populations (child care centers, schools, homes or offices occupied by women of childbearing age) & is expected to be completed for all occupied facilities by 2015. DP98 should be a high priority for the VI evaluation given the shallow depth to GW contaminated with high concentrations of chlorinated solvents, & the presence of an occupied building at the site.
EPA is concerned with the high concentrations of TCE measured in GW at this site, including the most recent result of 570 ug/L in August 2012 in the Five Year Review. When this GW concentration is input into EPA’s VI Screening Level (VISL) Calculator, Version 3.1, June 2013, & adjustments are made for average JBER GW temperature of 8 degrees C instead of the default of 25 degrees C, the calculated indoor air concentration exceeds 95 ug/m3. The screening level for occupational air exposure to TCE for women of childbearing age is 8.4 ug/m3. The screening value is a short term, noncancer, not to be exceeded, average 21 day exposure to women of reproductive age to prevent fetal heart malformations. The potential for vapor risk from chlorinated solvents at DP98 should be evaluated as soon as possible, & if the sampling indicates levels of concern, the Air Force should take immediate steps to mitigate the exposure.
Although not an issue that affects current or future protectiveness during this Five Year Review, monitoring data for GW at DP98 indicate variable conditions for breakdown of GW contaminants through the natural process of reductive dechlorination. The assessment of the natural attenuation remedy at this site has been in place for 10 years following the 2004 DP98 ROD. EPA agrees with the recommendation to further evaluate natural attenuation conditions before the next Five Year Review to better understand reducing conditions in GW. This information will support future remedy evaluations & track progress towards attainment of cleanup levels.
An addendum to determine the protectiveness of DP98 will be prepared by December 31, 2016
Sitewide – Elmendorf Air Force Base
The remedial actions at OU1, OU2, & OU6 have been implemented & are currently protective of human health & the environment but require follow-up actions as documented in the report & this letter to ensure they remain protective into the future. The remedial actions at OU 4, OU5, & DP98 have been implemented, however protectiveness is deferred due to the potential for VI at buildings in proximity to the GW plume.
EPA encourages the Air Force to start the vapor risk evaluation in 2014 due to the potential impact of low level, short term TCE exposure on fetal development. Additionally, GW plumes at OU2, OU4, & OU5 require optimization or alternative remedy evaluation under the process established in the FFA to reduce contaminant concentrations within reasonable timeframes. Overall the site protectiveness is deferred, & the follow-up actions need to be performed to ensure they remain protective in the long term.
Consistent with EPA’s August 1, 2011 memorandum “Program Priorities for Federal Facility Five-Year Reviews”, the Five-Year Review Guidance Section 1.3.3 has been superseded & the future Five-Year Review dates will be based on the completion date for this review to assure that the due dates will not change if the reports are early or late. The due dates for the subsequent Five-Year Reviews are March 17, 2019 & March 14, 2024.
Finally, the August 1 Program policies memorandum also calls for a summary of the EPA Superfund Sitewide Environmental Indicator Status for Sites undergoing Five-Year Reviews. The Environmental Indicators for Elmendorf AFB are posted on the EPA website at
Superfund Site Progress Profile Elmendorf Air Force Base. (http://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=1000155)
The Superfund Sitewide Human Health Exposure Indicator status will be changed to “Insufficient data to determine human exposure control status”. Due to uncertainty regarding exposures to VI from OU4, OU5, & DP98, the EPA cannot draw conclusions as to whether human exposures to TCE vapors are controlled in the occupied buildings in proximity to contaminated GW plumes.
The Superfund Sitewide Contaminated GW Migration indicator status will be changed to “Insufficient data to determine migration control status”. The EPA cannot draw conclusions as to whether the extent of contaminated GW plumes is defined at OU1 & OU5 as monitoring data suggest uncontrolled source areas at these OUs which contribute to plume instability. |
Louis Howard |
| 3/20/2014 |
CERCLA ROD Periodic Review |
ADEC appreciates the opportunity to review the fourth Five Year Review report for the Elmendorf Air Force Base (now JBER-E) Superfund site, in Anchorage Alaska. ADEC reviewed this report for technical adequacy, accuracy, and consistency with EPA guidance and the Elmendorf Air Force Base Federal Facility Agreement. Also included are additional recommendations and follow-up actions necessary to address issues raised in the Five Year Review that affect or could affect protectiveness. ADEC has reviewed the report which includes: Operable Units (OU) 1, 2, 4, 5, 6 and DP98, associated with Elmendorf Air Force Base on Joint Base Elmendorf-Richardson, Alaska. In general, ADEC agrees with the protectiveness determinations in this report.
General Comments
ADEC has commented on the matter of sampling for Perfluorinated compounds (PFCs) in this Five-Year Review at various fire-training areas/pits where Aqueous Film Forming Foam (AFFF) fire-fighting agents containing PFCs were used to extinguish fires. The Air Force’s response to ADEC’s comments was the following: “USAF guidance (Interim Guidance on Perfluorinated Compounds, 17 Sep 2012) will be followed to address potential release of perfluorinated compounds (PFCs). A centrally-funded project to conduct initial sampling has been authorized and programmed.” ADEC expects JBER to sample all of its former fire training areas/pits for PFCs [e.g. perfluorooctane sulfonate (PFOS), and perfluorooctoanoic acid (PFOA)] prior to the Fifth Five-Year Review to determine whether or not these compounds are contaminants of concern and require remedial action to protect human health, welfare, safety or the environment.
ADEC concurs with the deferred protectiveness determination for DP098 pending an assessment in 2015 of the vapor intrusion pathway at buildings above the contaminant plumes in DP098. DP098 should be a high priority for the vapor intrusion evaluation given the shallow depth to groundwater contaminated with high concentrations of chlorinated solvents (570 ug/L TCE), and the presence of an occupied building at the site. The potential for vapor risk from chlorinated solvents at DP098 should be evaluated as soon as possible, and if the sampling indicates unacceptable exposure risks, the Air Force should take immediate steps to mitigate the exposure.
An addendum to the Five-Year Review report should be prepared by December 31, 2016 which incorporates the results of the vapor intrusion assessment and any change on protectiveness for DP098. ADEC agrees with the recommendation to further evaluate natural attenuation conditions, under the process established in the Elmendorf Air Force Base Federal Facility Agreement, before the next Five Year Review to better understand reducing conditions in groundwater. This information will support future remedy evaluations and track progress towards attainment of cleanup levels.
ADEC appreciates the Air Force’s efforts in completing the Fourth Five Year Review and your project team on addressing ADEC’s comments to finalize the document. ADEC, EPA and JBER project managers have an excellent working relationship and ADEC looks forward to continuing this spirit of cooperation into the future.
|
John Halverson |
| 5/14/2014 |
Update or Other Action |
Draft 2013 Annual Field Activities Report received.
This report summarizes the 2013 annual long-term management activities, including remedial
action-operation (RA-O) and Record of Decision (ROD) requirements, conducted at Joint Base
Elmendorf-Richardson (JBER) Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) sites. The United States Air Force (USAF) has mandated a reduction
of long-term environmental liabilities and life-cycle costs through accelerated cleanup of
contaminated sites. As such, the Performance-Based Remediation (PBR) initiative has been
developed to protect human health and the environment in a cost-effective manner, while at the
same time reducing life-cycle costs.
In April 2012, Weston Solutions, Inc. (WESTON) was awarded a PBR contract from the Air Force Civil Engineer Center (AFCEC) (Contract Number FA8903-09-D-8589, Task Order No. 0016). The contract includes performing RA-O and ROD requirements at several JBER sites. The WESTON team performing the activities summarized in this report consists of WESTON and CH2M HILL Constructors, Inc. (CH2M HILL). WESTON executed project work on sites located within JBER-Elmendorf, while CH2M HILL executed project work on sites located within JBER-Richardson.
During 2013, five of the ten groundwater monitoring wells sampled had concentrations of COCs
that exceeded cleanup levels cited in the DP098 ROD. The leading edges of the plume continues
to appear stable, COCs in the downgradient wells (41755WL-07, 41755WL-09, 41755WL-15,
41755WL-16, and 41755WL-23) were all non-detect. Mann-Kendall trend tests show that there is a statistically significant increasing trend at the 95% level of significance for well 41755WL-08 for both TCE and cis-DCE and wells DP98INJ-02 and 41755WL-04 for vinyl chloride.
All other wells and COCs shown in the trend graphs have either a decreasing trend or no significant trend. Well 41755WL-02 has a decreasing trend for PCE, TCE, and cis-DCE. Well 41755WL-03 has a decreasing trend for cis-DCE. Well 41755WL-05 has a decreasing trend for cis-DCE and no significant trend for vinyl chloride. The 2013 data with elevated non-detect results were omitted from the trend graphs and Mann-Kendall trend tests. |
Louis Howard |
| 6/4/2014 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft CERCLA monitoring report for several sites including this one.
Page 2-2
2.2 Regulatory Requirements
Since trichloroethylene (TCE) is the primary COC at DP098, ADEC is requesting that 1,4-Dioxane be sampled for in GW at DP098 where TCE contamination exists or was previously detected above cleanup levels. 1,4-Dioxane cleanup levels have been promulgated since 2008 & AFCEE (now AFCEC) has research showing a positive association of 1,4-Dioxane with TCE contamination. Due to 1,4-Dioxane tendency to migrate ahead of the TCE GW plume, the existing monitoring well network at TCE sites, such as DP098, may not suffice to capture the full nature & extent of 1,4-Dioxane contamination in GW.
2013 Field Activities & Results
The text states: “A LUC inspection was performed at DP098 on 23 September 2013 & did not identify any LUC issues. A copy of the 2013 LUC inspection form for DP098 is provided in Appendix B.”
Appendix B
Site Inspection Checklist
Access & Institutional Controls (show location on a site map)
ICs Adequate: answer- N/A
Either the ICs are adequate or not, the answer should never be “not applicable” or N/A.
Overall LUC/IC questions that need to be asked: Were there any dig permits issued for the last 12 months at the site (i.e. 9/23/2012 – 9/23/2013)? If so, how many were there & were they followed as issued or not? If not, what corrective actions were taken to prevent violations of the dig permits in the future. Merely noting that on the day of inspection (9/23/2013) there was no evidence of excavation does not satisfy this data requirement. Comment applies to all forms filled out in this document.
NOTE: This applies to all LUC inspections on JBER-E & JBER-R.
DP098 Site Summary
Please clarify whether or not the increase in parent compound (TCE), as well as cis-DCE & vinyl chloride meet the 2004 Record of Decision (ROD) objectives. The ROD stated the MNA is an appropriate remedy based on plume stability & a decrease in contaminant concentations. Is the plume stable? Are contaminant concentrations decreasing?
The ROD also states after five years of monitoring, the Air Force will evaluate the progress of MNA. Additional GW modeling will be completed to provide estimates for the time frames to meet the cleanup goals.
Currently, it is estimated (by the 2004 DP098 ROD) natural attenuation will clean up GW within 35 to 75 (Year 2039 – 2079) years & soil outside the excavated source area within 18 to 48 years (Year 2022 – 2052).
Has the additional GW modeling (POST-ROD by 2010) been done as required & does the GW monitoring results for DP098 support the model’s conclusions? Is the increase in TCE & daughter products significant in aerial, vertical extent or volume than what was predicted to occur with the modeling results? Are other TCE sources present that would cause the TCE to increase?
Recommendation should be made here to continue DP098 ROD required annual LUC inspections with the next one due in 2014 (i.e. September 2014).
ADEC requests the Air Force clarify whether or not the 2011 Zones 1, 2, 3 Annual Report’s problems for DP098 have been resolved in 2012 or 2013:
“Current understanding of the DP98 site confronts two problems:
• The extent of contamination along the southwestern margin & at the upgradient edge of the northern lobe remains unbounded except by distant monitoring wells.
• Duration of natural flushing of the northern lobe through monitoring well 41755WL-08 is unknown. Concentrations of TCE & cis-DCE in this well may be stabilizing, such that a downward trend may be established in several years & support prediction of a cleanup date.
Recommendations:
Collect an additional round of samples from the two surface water locations (DP98SW-03 & -10) in the vicinity of monitoring well 41755WL-08 in 2012 to investigate further the relationship of the plume to surface water contamination & determine whether annual sampling would be beneficial.”
2012 sampling of DP098 did not include any surface water sampling (2.3 2012 Annual Field Activities Report) “The point of compliance at the kettle pond (DP98SW-01) was not located & no surface water was observed in the surrounding area.”
In 2013, there were no surface water samples from DP98SW-03 & -10, but sample location DP98SW-01 was sampled. No reason is given why sample locations DP98SW-01 & DP98SW-10 were not sampled (dry locations with no observable surface water, inaccessible, etc.). These locations are included on Figure 2-1 of this draft document.
|
Louis Howard |
| 11/5/2014 |
Document, Report, or Work plan Review - other |
EPA provided comments on the draft Annual CERCLA report.
DP98
Comment: Please enumerate the number or percentage of samples are Non-Detect due to LODs greater than cleanup levels? 4 out of 12? 30%? The sentence could be additionally clarified by describing that ND are reported at the LOD for these samples.
Comment:
Please consider the following modifications to Table 2-1
• Add 41755WL-03 to table and footnote that it had gone dry and not sampled.
• The analytes are presented alphabetically, but it would make more sense if they were in dechlorination order (PCE>TCE> cis 12 DCE >1,1-DCE> VC). This would also be consistent with the figures.
Comment: In the site summary for DP98, it is claimed "The leading edges of the plume continues to appear stable." This premise is contradicted two sentences later when the well 41755WL-08 is showing increasing trends for TCE and cis-DCE (and well 41755WL-08 is shown as the leading edge of the plume.) and Figure 2-7 shows increasing trends under Mann-Kendall analysis for this well.
Please address this discrepancy.
Please explain why seeps DP98SW-03 and DP98SW-10 have not been sampled since 2010.
No recommendations were given.
Comment: Please see the suggested changes to figures in future annual reports . Figure 2-1 is too low resolution and too cluttered to be very useful. Additionally, there are no groundwater contours or directional arrows and plume boundaries are drawn without sample results (examples include the bands of color differentiation for TCE to the north without supporting well data).
Comment: Consider deleting Figure 2-4. It seems odd to include this graph when it was dry at the sampling event in 2013 and data ends at 2012 for a 2013 report.
Comment: The site summary on page 2-4 claims the 'stable leading edge of the plume' however the MK statistics show a significant increasing trend. Please resolve the narrative to more accurately portray plume conditions at the leading edge. |
Louis Howard |
| 4/9/2015 |
Document, Report, or Work plan Review - other |
The Alaska Department of Environmental Conservation has received the final version of the document on April 8, 2015. The document covers several sites: DP098, FT023 (OU4), LF002 (OU6), LF003 (OU6), LF004 (OU6), LF059 (OU1), SD015 (OU6), SD024 (OU4), SD025 (OU4), SD029 (OU4), ST037 (OU5), ST041 (OU2), WP014 (OU6), OUB PRDA (CG039), and AVMA (DA089). ADEC has no further comments on the document and will approve the final version as submitted. |
Louis Howard |
| 7/23/2015 |
Update or Other Action |
Draft 2015 Annual Field Activities report received for review & comment.
During 2014, 6 of the 8 GW monitoring wells & one surface water location had COCs that exceeded cleanup levels cited in the DP098 ROD. The leading edge of the plume (well 41755WL-08) continues to have increasing levels of TCE & cis-DCE. COCs in the downgradient wells (41755WL-07 & 41755WL-09) were all non-detect.
Five-Year Review
Contaminants remain above cleanup goals; therefore the site is required to have CERCLA five-year reviews conducted until such time as the cleanup goals are achieved. The purpose of the five-year review is to evaluate the implementation & performance of the remedial actions. By 2008 the major components of the ROD had been implemented & the site was included in the third JBER-Elmendorf five-year review. Preparation of a remedial action report was recommended. The fourth five-year review report recommended a vapor intrusion evaluation be performed in accordance with EPA guidelines for each occupied facility in proximity to the TCE Plumes.
NOTE to file: Future five-year reviews for OUs 1, 2, 4, 5 and 6 and DP098 are necessary because contamination remains above levels that allow for UU/UE in these areas. The next five-year review is due on or before March 17, 2019.
Recommendations
DP098 is identified as a Red priority since the plume continues to have increasing levels of TCE, cis-DCE [daughter product], & vinyl chloride [daughter product]. A dense non-aqueous phase liquid (DNAPL) Evaluation is projected to be finalized in 2015. The report will provide additional information of the nature & vertical extent of the contamination at the site. The site priority may be updated in 2015 based on the report conclusion.
The 2015 recommendations for the future monitoring at DP098 include the following:
- Annually sample surface water location DP98SW-10 to investigate further the relationship of the plume to surface water contamination. |
Louis Howard |
| 8/10/2015 |
Document, Report, or Work plan Review - other |
Staff provided comments on the Annual CERCLA Report. Main comments were to correct mislabeled monitoring wells in the text and appendix and to analyze for 1,4-dioxane (associated with TCE contamination in groundwater).
See site file for additional information. |
Louis Howard |
| 10/25/2016 |
Update or Other Action |
Draft DNAPL Evaluation Report received for review and comment.
The historical data & 2014/2015 data support the following conclusions:
- DRO & GRO contamination were present in soils from about 165 to 196 feet amsl.
- Soil contamination remains above cleanup levels for DCE, PCE, & TCE with maximum concentrations of 1.8 mg/kg, 41 mg/kg, & 94 mg/kg, respectively. The deepest contamination above ROD cleanup levels was TCE encountered in 15DP098-SB-01 at 68.5 feet bgs (~128 feet amsl). Detections of TCE in the saturated soils below the LNAPL contamination limit of about 165 feet amsl indicate the existence of a deeper, independent CAH source, however no deep CAH DNAPL source was encountered between 40-80 feet bgs (158-118 feet amsl). While it is likely that DNAPL is present below the LNAPL, it is not practicable to precisely identify the source location & extent.
- The highest soil concentrations of TCE found were present within the petroleum hydrocarbon contaminated zone at 14DP098-SB-03 at 29-29.5 feet bgs (~169.5 ft amsl). The combined TCE & petroleum concentrations is approximately 250 mg/kg. While the presence of a NAPL mixture is indicated at low concentrations, it is insufficient to saturate the soil matrix pore spaces & would only be present as disconnected blobs or ganglia within the pore spaces & not expected to flow horizontally or vertically as a DNAPL.
- GW concentrations of DCE & TCE exceed ROD cleanup levels & elevated GW concentrations of GRO were present in the sample collected from the newly installed monitoring well DP98MW-07 [screened from 30–40 feet bgs (168-158 feet amsl)]. No exceedances of cleanup levels were indicated in the GW sample collected from the newly installed monitoring well DP98MW-08 screened from 65–80 feet bgs (133-118 feet amsl).
- Previous treatability studies to reduce dissolved phase TCE concentrations have indicated that between four methods tested, the injection of a mixture of hematite, gypsum, & emulsified vegetable oil within the TCE plume area was the most successful. Bioaugmentation could be a viable option to enhance emulsified vegetable oil injection
Based on the conclusions of the DNAPL evaluation, the following recommendations have been made:
- No further characterization of the upgradient source area is recommended, since multiple investigations (historical & recent) have not confirmed a deep, discrete DNAPL source.
- Continue GW monitoring at the site per the DP098 ROD.
- Complete a cost benefit analysis of enhanced treatment in the upgradient area.
See site file for additional information. |
Louis Howard |
| 11/7/2016 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft remedial action - operations and monitoring letter work plan.
Main comments were to ensure that both 1-methylnaphthalene and 1-methylnaphthalene are being reported when analyzing for PAHs. Also made comments regarding the need to review protectiveness in the next five year review for all contaminants that have changed in the recent 11/6/16 regulations update from what was listed in the ROD as a COC. Also requested chemicals that were detected above current cleanup levels in the Remedial investigation now above 11/6/16 cleanup levels also be looked at as part of the five year review.
See site file for additional information. |
Louis Howard |
| 11/16/2016 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft DNAPL evaluation report.
Main comments were regarding the new cleanup levels and contaminants that were COCs in the ROD, contaminants reported as part of the last annual monitoring report that are above the November 6, 2016 18 AAC 75 revised cleanup levels and the VI Guidance target levels for groundwater under residential and commercial land use scenarios. These issues will need to be reviewed as part of the five year review for protectiveness review. Finally, a request was made regarding the need to define the term practicable in light of this DNAPL evaluation since this issue was raised as a reason why DNAPL source location and extent could not be conducted, but no explanation was given.
See site file for additional information. |
Louis Howard |
| 1/24/2017 |
Update or Other Action |
ADEC received a groundwater monitoring report for several JBER sites. The report summarizes the 2015 annual long-term management (LTM) activities, including remedial action-operation (RA-O) and Record of Decision (ROD) requirements conducted at Joint Base Elmendorf-Richardson (JBER) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites.
Site DP098 is identified as a Red priority since the plume continues to have elevated levels of TCE, cis-DCE, and VC and an increasing trend for the downgradient edge. A DNAPL evaluation is projected to be finalized in 2016. The report will provide additional information of the nature
and vertical extent of the contamination at the site. The site priority may be updated in 2016 based on the report conclusion.
See site file for additional information. |
Louis Howard |
| 2/1/2017 |
Document, Report, or Work plan Review - other |
Staff reviewed & commented on the draft annual RA-O & Monitoring Report for select JBER CERCLA Sites.
Cis-1,2-DCE: The table lists a maximum detected result of 2,360 ug/L for this contaminant being sampled in 2015. The revised 18 AAC 75 Table C cleanup level of 36 ug/L (November 6, 2016) is more stringent than 70 ug/L listed in the OU6 ROD.
TCE: The table lists a maximum detected result of 902 ug/L for this contaminant being sampled in 2015. The revised 18 AAC 75 Table C cleanup level of 2.8 ug/L is more stringent than 5 ug/L listed in the OU6 ROD. Well 41755WL-05 detection limit of 5 ug/L is higher than the 2.8 ug/L cleanup level in Table C.
Vinyl Chloride: The table lists a maximum detected result of 1,490 ug/L for this contaminant being sampled in 2015. The revised 18 AAC 75 Table C cleanup level of 0.19 ug/L is more stringent than 2 ug/L listed in the OU6 ROD. There were two wells with reported “J” flagged results higher than the 0.19 ug/L cleanup level in Table C. Every well with a ND value had a detection limit higher than the cleanup level.
Please evaluate any changes to cumulative risk as a result of these more conservative cleanup level & any impacts to remedy protectiveness during the next Five Year Review.
Five-Year Review-The text states: “The purpose of the five-year review is to evaluate the implementation & performance of the remedial actions.” This is correct, however the review also assesses the protectiveness of the remedy with regards to impact of changes in standards, TBCs, exposure pathways, toxicity & other contaminant characteristics.
EPA Comprehensive Five-Year Review Guidance (June 2001):
4.2.1 How should I check the impact of changes in standards & TBCs?
“Generally, you should only consider changes in standards that were identified as ARARs in the ROD, newly promulgated standards for chemicals of potential concern [identified in the RI/FS or Risk Assessment since the ROD only lists COCs not COPCs], & TBCs identified in the ROD that bear on the protectiveness of the remedy.
As such, you should review any newly promulgated standards, including revised chemical-specific requirements (such as MCLs, ambient water quality criteria), revised action & location-specific requirements, & State standards if they were considered ARARs in the ROD.”
See site file for additional information. |
Louis Howard |
| 8/21/2017 |
Document, Report, or Work plan Review - other |
ADEC has reviewed the RTCs to ADEC's comments on the DP090 DNAPL Evaluation Report RTCs and approves the responses for incorporation into the final version. Only electronic copies are desired by ADEC. |
Louis Howard |
| 11/7/2017 |
Update or Other Action |
Letter report received for CY2016 [January 1, 2016 - December 31, 2016] Annual Land Use Control (LUC) and Institutional Control (IC) Monitoring at Joint Base Elmendorf-Richardson (JBER). This letter serves as the annual monitoring report on the status of LUCs/ICs in place on JBER-Elmendorf (JBER-E) and JBER-Richardson (JBER-R). The Air Force ensures compliance with LUCs by conducting periodic monitoring and site inspections. Formal LUC/IC inspections occur annually on JBER during late spring through early fall and are typically conducted by contract. A total of 55 sites were formally inspected. Random site inspections are also conducted throughout the year by JBER Restoration staff.
Discrepancies: Well 41755WL-03, which had one bolt sheared off. The bolt could not be removed and appears to be stuck in the casing lid. The outer casing was secured with a second bolt and the well is protected. The inner well casing of 41655WL-08 was cut down to a level below the
top of the outer casing and the outer lid was secured.
See site file for additional information. |
Louis Howard |
| 11/30/2017 |
Update or Other Action |
Draft VI report received for review and comment. The northeastern portion of Building 18220 is located within the boundary of a VOC groundwater contamination plume with the depth to groundwater approximately 15 feet bgs or less. The building is relatively airtight during normal operations, although office windows may be left open during warmer weather. Access to the building was limited to the VI sampling locations due to security restrictions, therefore, a thorough survey was not conducted to identify floor penetrations. No floor penetrations were noted during VI sampling. No non-VI ambient air COI contaminant sources were identified.
PCE was detected in indoor and outdoor air during FSE1 and FSE2. Concentrations of PCE in
indoor air were consistently higher than those in outdoor air. TCE was detected in indoor air,
primarily during FSE2, but was not detected in outdoor air during either sampling event.
Based on the above lines of evidence, the VI pathway is considered potentially complete at
Building 18220. The source for PCE in outdoor air represents an uncertainty in the VI pathway
evaluation. |
Louis Howard |
| 11/30/2017 |
Update or Other Action |
Draft VI report received for review and comment. Building 18224 is located within the boundary of a VOC groundwater contamination plume with the depth to groundwater approximately 15 feet bgs or less. The building is relatively airtight during normal operations, although two rollup garage doors may be left open during warmer weather. Several floor drains were noted within the building and the basement was flooded during both sampling events. Intrusion of groundwater into the basement suggests the potential for a complete VI pathway. No non-VI ambient air COI contaminant sources were identified.
TCE was detected in indoor air during FSE1 and FSE2. PCE was detected in indoor and outdoor
air only during FSE2. The maximum results for indoor air are at least one order of magnitude
higher than outdoor air for TCE and PCE. TCE and PCE were both detected in soil gas during
FSE1. There is no spatial bias apparent in the locations of the PCE and TCE detections in
ambient air or soil gas.
Based on the above lines of evidence, the VI pathway is considered potentially complete at
Building 18224. The presence of potentially contaminated groundwater in the basement provides
an unrestricted pathway for VI migration into the building.
See site file for additional information.
|
Louis Howard |
| 12/18/2017 |
Update or Other Action |
Draft RA-O report received for review & comment which includes this site. During 2016, five of the seven monitoring wells exhibited concentrations of COCs that exceeded cleanup goals cited in the DP098 ROD. Mann-Kendall (MK) trends are decreasing for TCE & DCE for monitoring wells located in the center of the plume (41755WL-02 & 41755WL-04). MK trends are increasing for TCE & DCE at the leading edge of the plume at monitoring well 41755WL-08. The MK trend for VC is increasing & the cis DCE trend is decreasing in DP98INJ-02 where an emulsified vegetable oil injection treatability study was performed in 2007.
This indicates an ongoing delayed effect from the injection of emulsified vegetable oil that is driving reductive dechlorination in this area. The trends at the leading edge of the plume indicate slower progress toward reaching cleanup goals. The COCs in the 2 remaining monitoring wells were both non-detect or below the ROD cleanup levels.
Site DP098 is identified as a Red priority since the plume continues to have elevated levels of TCE, cis-DCE, & VC & an increasing trend for TCE & cis-DCE at the downgradient edge. A DNAPL evaluation is projected to be finalized in 2017. The report will provide additional information of the nature & vertical extent of the contamination at the site. The site priority may be updated in the 2017 Annual RA-O & Monitoring Report based on the report conclusion.
See site file for additional information. |
Louis Howard |
| 1/8/2018 |
Document, Report, or Work plan Review - other |
Draft Vapor Intrusion study received for review and comment.
Main comments were to add more discussion on how the absence of building surveys in DP098 and the Silver Run Housing units affects the ability to adequately assess vapor intrusion risk in these areas. Other comments were to clarify the purpose for conducting sampling in order to help address the protectiveness deferred statements in the Fourth Five-Year Review. Clarification was also requested on the use of in labelled ratios for PCE/TCE soil gas, indoor air and whether they are actually attenuation factors instead.
See site file for additional information. |
Louis Howard |
| 2/13/2018 |
Document, Report, or Work plan Review - other |
Staff commented on the draft RA-O & M Report for select CERCLA Sites. Main comment was on well 41755WL-03 which was not sampled to identify the 0.14 feet of product in 2016, however in 2015 it was sampled and had 341 ug/L of cis-1,2-DCE and was below Table C cleanup levels for PCE, TCE, 1,1-DCE and vinyl chloride. Other comment made was to evaluate any changes to cumulative risk as a result of this more conservative cleanup level and any impacts to remedy protectiveness during the next Five Year Review for JBER-Elmendorf. This comment applies to all source areas with contaminants in groundwater above current cleanup levels (18 AAC 75 as amended through November 7, 2017).
See site file for additional information. |
Louis Howard |
| 10/17/2018 |
Document, Report, or Work plan Review - other |
Staff commented on the draft Annual RAO/LTM Report for Select CERCLA Sites (Sept. 2018). Staff requested review of changes to cumulative risk based on the more conservative amended cleanup levels (September 29, 2018). Other comments reiterated sampling for PFOS and PFOA at known sites with contamination from AFFF demonstrated by the 2018 Site Inspection Report and sampling groundwater and seeps at the sentry wells and early warning wells at the property boundary of JBER.
See site file for additional information. |
Louis Howard |
| 1/15/2019 |
Update or Other Action |
Draft 5 Year review received for comment. Issue: Cancer risks exceed 1 x 10-4 or have an HQ greater than 1 for the following non-COC chemicals: (in groundwater) benzene and (in surface water) cis-1,2-DCE and TCE. Recommendation: Investigate, by conducting a sampling event, the following chemicals for potential inclusion as remedy COCs: (in groundwater) benzene and
(in surface water) cis-1,2-DCE and TCE.
See site file for additional information. |
Louis Howard |
| 6/20/2019 |
Document, Report, or Work plan Review - other |
Staff provided comments on the Draft Supplemental RI DP009 JBER-Richardson, Alaska Dated April 2019. Staff requested clarification on whether the cumulative risk needs to meet the standard of hazard index (HI) = 1 and excess lifetime cancer risk (ELCR) of 1*10^-5 based on state regulation.
See site file for additional information. |
Louis Howard |
| 8/21/2019 |
Document, Report, or Work plan Review - other |
Staff reviewed the annual remedial action operations report for select CERCLA Sites. Main comments were to request the PCE statistical analysis for 2018 data be removed due to all PCE results flagged with "B" indicating it was detected in the associated method blank. Staff also requested the Air Force consider how it will deal with increasing vinyl chloride concentrations due to it being more toxic than the other daughter products of PCE.
See site file for additional information. |
Louis Howard |
| 1/7/2020 |
Document, Report, or Work plan Review - other |
Staff approved monitoring well decommissioning report for DP098. |
Louis Howard |
| 4/12/2021 |
Document, Report, or Work plan Review - other |
DEC submitted comments on Draft JBER Basewide UFP-QAPP dated February 2021. |
William Schmaltz |
| 5/19/2021 |
Document, Report, or Work plan Review - other |
DEC Reviewed and approved of Basewide Uniform Federal Policy - Quality Assurance Project Plan. QAPP summarizes general activities for a 5 year period on JBER. |
William Schmaltz |
| 5/28/2021 |
Document, Report, or Work plan Review - other |
DEC Approved of Final LTM and LUC Inspection Work Plan for select CERCLA sites dated May 2021. |
William Schmaltz |
| 8/9/2021 |
Document, Report, or Work plan Review - other |
DEC staff reviewed and provided comments on Draft 2020 Land Use Control report for Select CERCLA sites dated June 2021. Report summarized LUC inspections performed in December 2020. Most sites were covered in snow and a full inspection could not be performed until spring 2021. DEC requested that the spring 2021 inspections are included in the 2020 report or as a separate cover because they are a continuation of the 2020 inspections and separate of the 2021 inspections. |
William Schmaltz |
| 2/16/2023 |
Document, Report, or Work plan Review - other |
DEC reviewed and provided comments regarding the 2023 Letter Work Plan Remedial Action Operations and Long-Term Management, Draft, dated January 2023.The work plan describes the site inspections, maintenance activities, and groundwater, seep, and surface water monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. The scope of work briefly summarizes the site locations, sampling/monitoring schedules, and activities such as free-product removal from monitoring wells and monitoring/maintenance activities at the Operable Unit 5 wetlands. The details regarding the procedures for the remedial action operations and long-term management activities will remain consistent with the 2021 Uniform Federal Policy Quality Assurance Project Plan (UFP-QAPP). |
Ginna Quesada |
| 4/20/2023 |
Document, Report, or Work plan Review - other |
DEC reviewed and provided comments for the 2021 Annual Remedial Action-Operations and Long-Term Management Report for Select CERCLA Sites, Draft, dated December 2023. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections and sampling were recommended to continue for all applicable sites to ensure that conditions remain protective of human health and the environment. |
Ginna Quesada |
| 1/29/2024 |
Document, Report, or Work plan Review - other |
DEC reviewed the 2022 Annual Remedial Action-Operations and Long-Term Management Report for Select CERCLA Sites, Draft, dated October 2023. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections and sampling were recommended to continue for all applicable sites to ensure that conditions remain protective of human health and the environment. |
Ginna Quesada |
| 7/2/2024 |
Document, Report, or Work plan Review - other |
DEC approved the 2022 Annual Remedial Action-Operations and Long-Term Management Report for Select CERCLA Sites, Final, dated June 2024. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections and sampling were recommended to continue for all applicable sites to ensure that conditions remain protective of human health and the environment. |
Ginna Quesada |
| 11/12/2024 |
Document, Report, or Work plan Review - other |
DEC approved the 2023 Annual Remedial Action-Operations and Long-Term Management Report for Select CERCLA Sites, Final, dated October 2024. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections and sampling were recommended to continue for all applicable sites to ensure that conditions remain protective of human health and the environment. |
Ginna Quesada |
