| Action Date |
Action |
Description |
DEC Staff |
| 8/2/1988 |
Update or Other Action |
Operable Units' source areas that correspond to RCRA SWMUs from the RCRA RFA. SD25 IS-2 Bldg. 42-425 Floor Drain. This site was used for aircraft maintenance, -100 gals/month of PD-680* was washed down drains into dry wells.
*NOTE TO FILE: PD-680 Each item the Govt. orders must have an N.S.N, a National Stock Number, unless the Agency gets special permission to local purchase the item. Each N.S.N. item goes out for bid and has an associated minimum specification. The specification for PD-680, aka. Stoddard Solvent, back in the 1980's and before it was for a petroleum based degreaser with a specified flashpoint. No requirement for non-halogenated existed. Besides that, because Alaska was so far from vendors that supplied the Govt., many federal agencies in Alaska purchased solvents locally. There were no qualifications on those solvents and most often halogenated solvents worked with less effort than pure petroleum distillates, so they were preferred.
NSNs ordered through the PD-680 specs had some batches with TCE, Methylene chloride, etc; it depended on who the supplier to the Govt.was at the time. So as a result between 1980 and 1983, some PD-680 batches were in fact halogenated. For historical releases it pays to be suspicious of drums that say PD-680 or Stoddard Solvent. |
Louis Howard |
| 3/8/1989 |
Update or Other Action |
USAF Thomas A. Ritz Major, Acting Chief, Engineering & Environmental Planning Branch sent letter to Sue Curtin Black & Veatch. Buildings 42-400, 42-425, 43-550, 42-300, 43-410, 43-450, 21-900, and 32-060 floor drains: Originally, minor spillage and products from cleaning operations in these facilities were washed into floor drains, and from there to dry wells. Present conditions are below. Since as-builts are old and not clear, this information may not be totally correct.
a. IS-1, Building 42-400: Floor drains run into two oil-water
separators. NOTE: Building 42-400 is now 15455 on 30th Street "Maintenance Dock Hangar 10".
b. IS-2, Building 42-425: Sanitary sewer runs along side of building, unclear whether floor drains run into it or not. NOTE: Building 42-425 is now 16430 on Airlifter Drive "Hangar 11".
c. IS-3, Building 43-550: Sanitary sewer runs along side of building, do not know whether floor drains run into it or not. NOTE: Building 43-550 is now 16521 on 32nd Street "Mobility Maintenance Hangar 14".
d. IS-4, Building 42-300: Floor drains run into an oil-water separator and then into the storm drain on the east and west side of the building. NOTE: Building 42-300 is now 14410 on 30th Street "AWACS Hangar 8".
e. IS-5, Building 43-410: Floor drains are connected to septic tank and leach fields at south side of building. NOTE: Building 43-410 is now 16710 on Talley Avenue "Alert Vehicle Facility".
f. IS-6, Building 43-450: Floor drains probably go to the septic tank and leach pits east of the building and across the railroad track. NOTE Building 43-450 is now 16716 on Talley Avenue "Hangar 15".
g. IS-7, Building 21-900: The floor drains run through sumps to remove sand and grit and dump right into the storm drain on the north side of the building. The floor drains for the mechanical room run out the south side of the building and into a seepage pit. There is also a catch basin on the south side of the building that runs into a seepage pit. NOTE: Building 21-900 is now 6211 on Arctic Warrior Drive "Maintenance Trans. HQ".
h. IS-8, Building 32-060: Although sanitary sewers run near the building, it appears that floor drains go directly to dry wells. NOTE: Building 32-060 is now 7309 on Johnson Avenue "Hangar 5". |
Jennifer Roberts |
| 4/19/1990 |
Site Added to Database |
Petroleum, metals, pesticides, chlorinated solvents. |
Louis Howard |
| 5/1/1990 |
Update or Other Action |
Black and Veatch Remedial Investigation (RI); floor drains from maintenance facilities in the past or presently discharged to dry wells. Seven sites are identified in this report. Report sites IS-1 through IS-8, pages 4-134 to 4-172 volume 1. The groundwater at these sites varies from 20 to 40 feet below the surface and flows towards the southwest for sites IS-1 through IS-4. Sites IS-5 ad IS-6 flow towards the west-northwest. BTEX, chlorinated solvents and other chemicals associated with the maintenance facilities were detected in soil and groundwater samples taken from these sites. Site IS-1 (page 5-79, Volume 2) has the greatest potential for impacting drinking water quality. IS-1 is Building 42-400.
Remediation described in Volume 2 consists of product recovery and air stripping of pumped groundwater. Two (2) to six (6) years were estimated for cleanup operations to be completed (1992-1996). Sites IS-7 and IS-8 flow towards the south. Contamination is largely subsurface, however, PAH and chlorinated organic compounds were identified at the ground surface at site IS-6 (Building 43-450). No further action was recommended for site IS-2 (Building 42-425) and site IS-5 (Building 43-410). |
Jennifer Roberts |
| 1/8/1991 |
Site Ranked Using the AHRM |
Initial ranking. |
Louis Howard |
| 10/31/1991 |
Update or Other Action |
CH2MHILL site summary identified site as having 3 Building #s 43-550 Engineering Science and DEC's # is 42-550, EPA calls it 45-550. A water sample was found to be contaminated with organochlorine pesticides alpha-BHC 26 ug/l and delta-BHC 1.7 ug/l. Alpha-BHC exceeds compliance level of .013ug/l and there was no discussion on the occurrence of pesticides in the groundwater samples from previous investigations.
The fate of 55 gallons/month of PD-680 and the potential for off source migration has not been identified and the recoverable metals detected in groundwater samples which exceeded federal/state action levels were not discussed. |
Jennifer Roberts |
| 10/31/1991 |
Update or Other Action |
CH2MHILL site summary document ANC31026.E6.11 for Operable unit 4 source # SD24 (IS-1) Building 42-400 Hangar 10 found several data gaps from previous investigations. Additional remedial investigations are warranted at source SD24 and implementation of an interim remedial action (IRA) at this source is also warranted due to the presence of free product detected in well W-18 and the high TPH levels detected in soils collected from well W-19, the possibility of alpha-BHC contamination at source SD24 being caused by the migration of contaminant from SD26 should be investigated.
Additional boring/monitor wells should be installed to further define the source characteristics and vertical extent of contaminant plume. Finally further discussion of the recoverable metal concentrations detected in the groundwater samples: specifically those that exceeded federal/state action level MCLs is warranted. |
Jennifer Roberts |
| 10/31/1991 |
Update or Other Action |
CH2MHILL site summary for Building 42-300 Hangar 8 SD27 site summary states that effort should be made to explore and confirm the source of the pesticides that were detected, as well as investigating the source of mercury contamination detected above the maximum contaminant level (MCL). Previous reports failed to include detailed information related to the presence and the location of domestic and industrial wells in the surrounding area. It is recommended that water samples be collected in sufficient numbers (at least two) from the wells if found to determine the level of contamination. |
Jennifer Roberts |
| 10/31/1991 |
Update or Other Action |
CH2MHILL review for hangar 11 Building 42-425 source SD25(IS-2) showed data gaps at this site: fate of 100 gallons/month of PD-680 and potential for off source migration has not been identified, no soil gas surveys done on sources SD24-SD27, direction for the groundwater flow and associated gradient was estimated from on source monitor well and regional water level data from nearby source areas. Recoverable metals detected in groundwater samples which exceeded federal/state action levels were not discussed. |
Jennifer Roberts |
| 11/12/1991 |
Enforcement Agreement or Order |
Federal Facility Agreement under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) signed for docket # 1089-07-19-120. The agreement ensures that the environmental impacts associated with past and present activities at the Base are thoroughly investigated and appropriate removal and/or remedial action(s) taken as necessary to protect human health and the environment. Elmendorf Federal Facility Agreement signed.
The general purposes of this Agreement are to: (a) Ensure that the environmental impact associated with past and present activities at the Site are thoroughly investigated and appropriate removal and/or remedial action(s) taken as necessary to protect the public health, welfare, and the environment.(b) Establish a procedural framework and schedule for developing, implementing, and monitoring appropriate response actions at the Site in accordance with CERCLA, the NCP, Superfund guidance and policy, RCRA, RCRA guidance and policy, and applicable state law.
The FFA divided the CERCLA study source areas at Elmendorf AFB into the following seven operable unites (OUs), on the basis of geographic proximity and similar source characteristics or contaminants:
- OU1 Landfills (LF05, LF07, LF13, LF59, OT56)
- OU2 Tank Spill Sites (ST20, ST41, including the ST41 Sludge Disposal Area)
- OU3 Central Containment Area (SD16, SD31, SD52, SS21)
- OU4 Northern Containment Area (SD24, SD25, SD28, SD29, FT23, SSl0)
- OU5 Southern Containment Area (ST37)
- OU6 Surface Disposal Sites (LF02, LF03, LF04, SD15, SD73, WP14)
- OU7 Limited Field Investigation (SS19)
Proposed listing on NPL was 07/14/1989 and Final listing on NPL was on 08/30/1990.
SD25 (formerly IS-2) Bldg. 42-425 Floor drain. This site was used for aircraft maintenance, 100 gallons per month of PD-680 was washed down drains into drywells.
See site file for additional information. |
Jennifer Roberts |
| 11/12/1991 |
Update or Other Action |
Jennifer Roberts Federal Facility Coordinator sent letter to Joe Williamson and Rich Howard pursuant to Section 9.1 of the Elmendorf Air Force Base Federal Facility Agreement (FFA). ADEC designates Jennifer Roberts as the Project Manager and Ron Klein as the Alternate Project Manager for all activities covered under the FFA. |
Jennifer Roberts |
| 12/30/1991 |
Update or Other Action |
EPA sent letter to AF Rich Howard and Joe Williamson. The notification will serve as an addendum to the previous letter of November 4, 1991 which designates the USEPA project managers pursuant to Section 9.1 of the Elmendorf Air Force Base (EAFB) Federal Facilities Agreement (FFA). Marcia Combes will serve a lead remedial project manager (RPM) for base wide activities, as well as Operable Units (OUs) 2, 3, 5, 6, 7. Michele Poirier-McNeill will serve as lead RPM for OUs 1 and 4. In addition, both RPMs will serve as an alternative RPM on OUs for which they are not the lead. For communication and correspondence purposes, the lead RPM should be the point of contact, and the alternate should be copied. |
Jennifer Roberts |
| 7/17/1992 |
Preliminary Assessment Approved |
Memorandum for a meeting held at CH2MHILL/ANC on July 8, 1992 subject: OU4 IRA Planning. Purpose was to discuss the preliminary results of the OU4 Limited Field Investigation (LFI) field work and reach consensus among the project managers on which OU4 source areas would be appropriate for an Interim Remedial Action (IRA). General criteria for an Interim Remedial Action (IRA):
1) contamination verified above action levels (EPA and ADEC guidance levels);
2) point source contamination defined and accessible;
3) IRA implementable;
4) IRA won't interfere with final remedy; and
5) IRA should prevent further release of contaminants.
SD25 (Building 42-425): Contamination above action levels detected, soils encountered that may have been saturated (perched water table? wastewater discharge?); Point source of contamination not well defined; area also has USTs and may also be affected by the Fire Training Area source area FT23; Only action now may be to stop any further discharges from building; and Consensus: not a candidate for IRA; include in future Remedial Investigation (RI). |
Jennifer Roberts |
| 9/16/1992 |
Update or Other Action |
USAF letter to Jennifer Roberts regarding "Revisions to Elmendorf AFB Federal Facility Agreement (FFA) Scope of Work for Operable Units (OU) 4 and 7." As a result of the 1992 field investigation, the USAF requests to move FT23 from OU7 to OU4. Based on the results of the Limited Field Investigation (LFI) it appears FT23 may be the source of contamination observed in past investigations at SD24, SD25, SD26, and SD27.
Delete the requirement of an interim remedial action (IRA) at OU4. Based on the LFI, the remedial project managers identified the dry wells at SD24, SD28, and SD31 as potential IRAs. However, further review of the results of the LFI, indicate only the sludge at the bottom of the dry well at these sources were sampled and no soil samples were obtained. At this time there is no evidence of soil contamination in the immediate vicinity of the dry wells. Without additional investigation of these wells, it does not appear an IRA is warranted. Instead of an IRA, we will pursue funding to remove the sludge in each dry well. ADEC project manager Jennifer Roberts signed document to show its concurrence. |
Jennifer Roberts |
| 3/26/1993 |
Update or Other Action |
DOD and ADEC joint Technical Memorandum of understanding signed concerning the Base wide Groundwater (GW) signed by: ADEC Jennifer Roberts RPM and USAF Joseph Williamson Chief Environmental Programs & Restoration. Due to the base wide GW study and the FY92 field work that occurred at Operable Units (OUs) 1, 2, and 5 it appears a large portion of the GW flows into OU5 (attach. 1-contour map). Based on this fact, Elmendorf (EAFB) will move all upgradient GW into the OU5 Feasibility Study, Proposed Plan and Record of Decision (ROD). This means addressing all GW from upgradient sources (CERCLA (ST20, OUs 3 and 4) and OUs 1 and portions of OU2) and SERA) at OU5 instead of at each individual source area (see attach. 2-Area Map). Sites with free phased product would be looked at to see if there is an available technology to clean them up in a cost effective way. Soil contamination would be addressed at the source areas. NOTE: addressed at the source areas is interpreted by ADEC as removal through excavation or active treatment systems (e.g. high vacuum extraction, bioventing, etc...).
|
Jennifer Roberts |
| 2/15/1994 |
Update or Other Action |
SERA Phases 1A & 1B Site Assessment report includes site ST64 JP-4 Leak (IRPIMS Site 52). Site ST64 is located on Burns Road, approximately 2,000 feet from Building 42-425 (Hangar 11). The site is bordered to the south by Taxiway 6, to the north by a 25,000-gallon deicer tank, and to the east by Hangar 11. Site ST64 is comprised of four USTs: Tank 425D, a 500-gallon diesel UST; Tank 425C, a 3,000-gallon diesel UST; Tank 425B, a 3,000-gallon JP-4 UST; and Tank 425A, a 2,500-gallon mogas UST.
The groundwater samples analyzed from wells 52WL01, 52WL02, and 52WL03 had lead concentrations of 82.9, 33.1, and 134 ug/L. Soil: 52BH02 28' bgs DRO 1,000 mg/kg, GRO 2,700 mg/kg, 3 mg/kg benzene, 50 mg/kg toluene (highest), 20 mg/kg ethylbenzene (highest), 110 mg/kg xylenes (highest). 52BH01 28' bgs had DRO 460 mg/kg, 1,900 mg/kg GRO, 14 mg/kg toluene (highest), 12 mg/kg ethylbenzene, 45 mg/kg xylenes.
Groundwater: 52WL02-3.2 mg/L DRO, 1.9 mg/L GRO, 21 ug/L benzene, 330 ug/L toluene, 190 ug/L ethylbenzene, 760 ug/L xylenes. 52WL03: 0.5 mg/L DRO, 7.9 ug/L benzene, 2.6 ug/L toluene, 2.6 ug/L ethylbenzene and 1.6 ug/L xylenes.
The USTs are out of service and should be closed/removed, and remedial systems should be
considered if associated contamination cannot be removed at that time.
If soil contamination is encountered during removal of the USTs, it should be handled in
accordance with ADEC regulations and guidance.
The groundwater requires remediation. The results of the Operable Unit 4 investigation should be reviewed prior to consideration of groundwater remediation at site ST64. OU4 is located east of the site and may be contributing to the high concentrations of lead and benzene in the groundwater. |
Louis Howard |
| 5/15/1994 |
Update or Other Action |
OU4 Hangar 10/OU2 ST41 Work plan for Engineering Evaluations/Cost Analysis (EE/CA) received. The purpose of the EE/CA is for remediation of the groundwater contamination at the site. The broader scope of the document is to allow AFCEE, EPA, and Engineering Science to demonstrate that intrinsic remediation works. All data collected under this program will be used as input into the Bioplume II groundwater model in support of intrinsic remediation with long term monitoring remedial option for the restoration of fuel hydrocarbon contaminated groundwater.
Depth to groundwater is 21-27 feet below ground surface. Local horizontal gradient is approximately 0.0023 feet/ft. In hangar 10 area the top of the Bootlegger Cove Formation is at 90 feet deep and southwest of hangar 8 it is at 35 feet. One pumping test was conducted in 1988 in the sand and gravel of the outwash aquifer (Black and Veatch 1990). The data were reanalyzed by Radian Corp. (1994). These results indicated a hydraulic conductivity range of approximately 1 X 10-1 to 3 X 10-1 centimeters per second (cm/sec). |
Jennifer Roberts |
| 9/15/1994 |
Risk Assessment Report Approved |
Risk assessment combined with RI/FS final version received and approved. Twelve (12) constituents were identified as major contributors to groundwater risk. Eight (8) were identified as contributors to carcinogenic groundwater risk: benzene, chloromethane, dieldrin, 1,1-dichloroethene, 1,2-dichloroethane, chloroform, trichloroethene, and carbon tetrachloride. Four (4) constituents were principal contributors to non-carcinogenic groundwater risk, including toluene, ethylbenzene, cis-1,2-dichloroethene, and trichloroethene. Results of the risk evaluation for soils indicated six constituents as primary contributors to the carcinogenic risk in soil, including benzo(a) pyrene, benzo(b)fluoranthene, dibenzo(a,h)anthracene, benzo(a)anthracene, PCB-1260, and benzo(k)fluoranthene. Non-carcinogenic risk in soil did not exceed an HQ of 1.0.
The results of the risk assessment indicate that each of the six soil and five of the six groundwater areas of interest have a carcinogenic risk in excess of 1.0 x 10-6 using the most conservative residential estimates. At the Asphalt Drum Storage Area, no groundwater risks were identified.
Ecological risk assessment: Ecological quotients for moose did not exceed 1.0 for moose. EQs of 1.0 were exceeded for copper and lead for meadow voles at OU4. None of these exceedances appear to be highly significant for the following reasons: the overall nature of the methodology used was conservative. In several cases the calculated doses, reference criteria, or measurement endpoints were inappropriate for this site because even normal background concentrations caused exceedances. Finally, the relatively uniform distributions of concentrations of manganese, selenium and thallium across all the sites is not typical of highly contaminated areas. |
John Halverson |
| 9/15/1994 |
Site Characterization Report Approved |
Remedial investigation/feasibility study report final version received and approved.
NOTE TO FILE: There were several fuel range hydrocarbons detected in groundwater at Hangar 11. ranging from 2.43 mg/L to 10.8 mg/L unknown compounds within Jet Fuel Range (OU4W-8) and 0.699 mg/L to 49.2 mg/L unknown compounds within the Gasoline range (OU4W-8). These are "unknown" compounds that do not exactly match the chromatographic pattern of the calibration compounds. They may be the result of degradation of fuel compounds or naturally occurring organic matter.
Used in combination with diesel, gasoline, and jet fuel concentrations this information can provide "extent of contamination information." These compound concentrations are produced from SW8Ol5ME and SW8015MP at no additional analytical cost.
Hangar 8/10 Plume Area had maximum detected concentrations as follows:
2.56 mg/L unknown compounds within kerosene range (W-18) and 0.298 mg/L to 4.97 mg/L unknown compounds with gasoline range (OU4W-10) |
John Halverson |
| 11/30/1994 |
Document, Report, or Work plan Review - other |
ADEC provided the USAF with comments on Intrinsic Remediation/Engineering Evaluation Cost Analysis for Hangar 10 dated October 1994. General Comments-Intrinsic remediation (natural attenuation) coupled with long term monitoring and institutional controls appears to be a feasible option as presented in the modeling for the BTEX contaminated ground water at Hangar 10 in Operable Unit (OU) 4. ADEC concurs that if the point-of-compliance (POC) wells indicate BTEX in the ground water exceeds the federal regulatory standards, then additional corrective action will be necessary to remediate the ground water at this site.
The text states the low dissolved oxygen (DO) levels (0.8 mg/L) will be assumed to be background for modeling purposes. This DO level is realistic if one were to not consider using biosparging as a remedial action technology. However, by not utilizing a modeling scenario where the DO level is increased (i.e. through biosparging), the statement that "... DO may not be the most important electron acceptor in Hangar 10 vicinity." could be incorrect.
The text states anaerobic decay co-efficient was set to zero so only aerobic biodegradation was simulated. Using the low DO loevel of 0.8 mg/L as background is not appropriate for this scenario if it is to prove or disprove biosparging as a remedial action. The modeling scenario should include DO concentrations at a higher level to better simulate biosparging of the BTEX plume contaminants in the vicinity of Hangar 10.
|
Louis Howard |
| 1/19/1995 |
Update or Other Action |
OU5 Groundwater (GW) Modeling Report received. The objectives of the modeling task were to: Evaluate the movement of contaminants across Elmendorf AFB (EAFB) and within Operable Unit (OU) 5; Predict migration over the next 30 years; and Determine if selected receptor points along Ship Creek and an unnamed beaver pond will be impacted. A 3 dimensional finite element model (SALT) was selected because of its versatility in handling complex geology and boundary conditions. It was modified to improve the program's efficiency, to include contaminant decay and site specific boundary conditions along Ship Creek. This revision was called SALT 3 consists of GW flow and contaminant transport models. The hydrogeology of the modeled area was evaluated using lithologic data collected from all available boreholes within the modeled area and water level data collected from shallow water table monitoring wells in March and September 1993.
After a review of the data from September 1993 GW sampling and available OU 1, 2, and SERA site data, benzene and trichloroethene (TCE) were selected as representative compounds due to their potential health impacts. Concentrations in the recharge over the water table was set to zero except for at source areas. Since improvement in soil quality is expected over time, the sources were assumed to cease contributing benzene and TCE to GW after 5 years. All levels in the recharge zone were set to zero at the end of the first 5 years.
The conclusions show benzene and TCE will migrate toward the south and decline over time. Because of infiltration, there may be some localized areas that experience a temporary increase in level as a "pulse" migrates toward the south. Benzene will be detectable in GW for over 20 years, however, the levels in GW base wide should be below the MCL after 15 years (1993-2008). TCE levels will be detectable in GW after 30 years (2023) and should be less than the MCL base wide after 20 years (2013). |
Jennifer Roberts |
| 4/11/1995 |
CERCLA Proposed Plan |
Final Proposed Plan received. Soils. Soil contamination at OU 4 was detected in samples of both deep soils (> 5 feet) & shallow soils « 5 feet). Gasoline, diesel, jet fuel, BTEX, & other fuel-related contaminants are present in the soils at concentrations exceeding cleanup standards at the areas comprising OU 4. Polychlorinated biphenyls (PCBs) also were detected at very low concentrations in soils at isolated locations, but were well below cleanup standards & acceptable risk. Low levels of heavy end contaminants, such as asphalt & tar by-products, were also commonly found in the OU4 soils. Asphalt type contaminants were found at low levels at each of the OU4 source areas in shallow soil samples.
These contaminants were detected in isolated occurrences that were generally below the acceptable risk ranges. Since these types of contaminants are relatively immobile, they do not tend to percolate into the GW. If a hypothetical resident eats the contaminated soil, there would be a risk.
In the deep soils, the primary contaminants detected were fuels (dieseL jet fuel, etc.). These contaminants, although posing no current risk since they are buried, can percolate into the GW & may contribute to GW contamination sometime in the future. Relatively high levels of fuels were detected in the deep soil at two locations at Hangar 10/11. This contamination was detected at depths of about 25 feet above the GW table. Because of the high levels of fuels detected, some action may also be required at these locations to protect the GW from future contamination. No other fuels contamination in the deep soils at OU4 poses a significant risk to GW.
GW. The GW screening program identified several contaminant plumes in the upper aquifer at the source areas. The plumes are totally contained on base property & do not currently affect any GW users. The organic contaminants of concern exceeding standards in GW include fuels, BTEX constituents, & chlorinated solvents.
SD24, SD25, & SD26 (a.k.a. hangar 10,11,14) are part of OU4 west. The preferred alternative for GW at all source areas is Alternative G2 (institutional controls with intrinsic remediation). Alternative S2 (institutional controls with intrinsic remediation) is also the preferred alternative for shallow soils at all the source areas, & for the deep soils at Hangar 15. Alternative S5 (bioventing) is the preferred alternative for the deep soils at the FTA, ADSA, & Hangar 11. Alternative S5 was chosen because these three areas could act as a future source of GW contamination & thus pose a human health & environmental risk.
Preferred alternative for deep soils (> 5 ft.) at SD24/SD25 is bioventing for the gasoline, diesel & kerosene contamination found there. Benzene, ethylbenzene, toluene are the COCs in GW which are also being treated by institutional controls/intrinsic remediation (IC/IR). Cleanup of GW by IR is expected to be no longer than 13 years (2008) & cleanup of the deep soils is expected to take longer than 2 years.
The preferred alternatives were chosen on the basis that assumptions behind the human health risk calculations are very conservative, However, no alternative will be selected until after the public comment period. It is extremely unlikely that future residents would use contaminated water from the upper aquifer for drinking & showering. Upper aquifer wells are not being used for any purpose, & they are not expected to be used in the future. It is also highly unlikely that residence would be constructed in these areas, since they are adjacent to hangars & runways.
See site file for additional information. |
Jennifer Roberts |
| 10/4/1995 |
Cleanup Plan Approved |
ADEC commented on the Base Bioventing Treatability Study OU4 dated September 1995. ADEC concurs with the treatability design report as presented and the rationale supporting bioventing at the Fire Training Area ( FT23), hangar 11, and the Asphalt Drum Storage Area (ASDA). |
Louis Howard |
| 10/10/1995 |
Cleanup Level(s) Approved |
Cleanup levels for soil is level "D" : DRO 2,000 mg/kg, GRO 1,000 mg/kg, Xylene 100 mg/kg. Groundwater benzene 5 ug/L ethylbenzene 700 ug/L, and toluene is at 1,000 ug/L. Estimate at time of ROD was signed in 1995 for cleanup in groundwater to be concluded by natural attenuation was 13 years (2008). |
Louis Howard |
| 10/10/1995 |
CERCLA ROD Approved |
ROD states hangars 10, 11, 14 (SD 24, 25 & 26) GW contamination will be intrinsically remediated & have institutional controls (ICs) on land use & water use restrictions to restrict access to the contaminated GW until cleanup levels have been met.
Deep soils at the FTA, the ADSA, & Hangar 10/11 [SD24/SD25] will be treated with bioventing to accelerate degradation of contaminants in those locations. Deep soils at other source areas will be allowed to degrade through intrinsic remediation. The Air Force will investigate & implement other remedial alternatives should the selected remedies prove to be unsuccessful at meeting the required cleanup levels.
Specific components of the selected remedy consist of the following:
GW- Institutional controls on land use & water use restrictions will restrict access to the contaminated GW throughout OU 4 until cleanup levels have been achieved. GW will be monitored & evaluated semi-annually to assess contaminant migration & timely reduction of contaminant concentrations by intrinsic remediation. This will include five-year reviews to assess the protectiveness of the remedial action, as long as contamination remains above cleanup levels. A monitoring plan will be prepared to address the details involved in sampling. All GW is expected to be cleaned up within thirteen years.
Soil-Institutional controls on land use will restrict access to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved. Deep soils at specified locations & depths at the FTA, the ADSA, & Hangar 11 will be treated with bioventing to accelerate degradation of contaminants in those locations. Deep soils at other source areas will be allowed to degrade through intrinsic remediation. Both shallow & deep soils will be monitored & evaluated bi-annually to assess contaminant migration & timely reduction of contaminant concentrations by intrinsic remediation. This will include five-year reviews to assess the protectiveness of the remedial action, as long as contamination remains above cleanup levels.
When concentrations in the bioventing areas are below cleanup levels, bioventing will be discontinued. A monitoring plan will be prepared to address the details involved in sampling. All soils are expected to be cleaned up within eleven years. The remedy will be implemented after the Remedial Design has been completed. A treatability study for bioventing design is currently in progress. Bioventing will be implemented until cleanup levels have been achieved. The actual timeframe for intrinsic remediation at the other source areas is not known, but GW & soil modeling predict cleanup levels will be achieved in 10 to 15 years.
GW & soil will both be monitored to evaluate the progress of intrinsic remediation processes. Further response actions, coordinated with the regulatory agencies, may be considered if monitoring finds unacceptable contaminant migration occurring, or unacceptable reduction in contaminant concentrations through intrinsic remediation.
See site file for additional information. |
Louis Howard |
| 10/10/1995 |
Institutional Control Record Established |
Institutional controls (ICs) established by signing of ROD and subsequently been enforced by land planning department at the Base and environmental restoration staff oversight. These institutional controls on land use and water use restrictions are to restrict access to contaminated groundwater throughout OU4 until cleanup levels have been achieved, ICs on land use will continue to restrict access to the contaminated shallow soils (< 5' deep) in OU4 until cleanup levels have been achieved. Deep soils (> 5' deep) at specified locations and depths at the FTA, the ADSA, and hangar 11 will be treated with bioventing to accelerate degradation of contaminants in those locations.
No current receptors exist for the groundwater at the Base due to the institutional controls (ICs). As a requirement of previously signed RODs for the Base, ICs have been established to restrict the use of the shallow aquifer in the outwash plain on Base. These restrictions are enforced through the Base Comprehensive Plan (BCP). Projects and other activities are reviewed during the planning stage to ensure compliance with the BCP. In addition, construction projects and other activities also undergo an environmental review. This review helps ensures compliance with groundwater use restrictions. |
Louis Howard |
| 11/15/1995 |
Update or Other Action |
Basewide Support & GW Monitoring Program, Analytical Results for OUs 3/4 - Round 2 received. The objective of GW monitoring at OUs 3 & 4 is to compare concentrations of contaminants of concern (COCs) to historic concentrations & available background concentrations, at each respective well. Analytical methods utilized for each OU are based jointly on the results of the RI/FS programs conducted at OU 3, OU 4, & OU 5, during which COCs were initially identified.
OU4-MW-8 and 52-WL-04 are associated with Hangar 10 in OU4. Exceedances (based on 2018 18 AAC 75 Table C groundwater cleanup levels): Benzene 124 ug/L (5 ug/L), ethylbenzene 280 ug/L (15 ug/L), gasoline range organics (GRO) 5.11 mg/L (2.2 mg/L) and xylenes 523 ug/L (190 ug/L).
52-WL-04: no exceedances. |
Louis Howard |
| 10/17/1996 |
Update or Other Action |
Air Force memo: Restricted Use of the Shallow Aquifer on EAFB signed by William R. Hanson P.E. GM-14 Chief Environmental Flight dated October 17, 1996 Memorandum for 3 SPTG/CEC/CEO from 3 SPTG/CEV
1) Due to the contamination and commitments to EPA/DEC the use of the shallow aquifer for any purpose on is not allowed. Attached Facilities Board minutes-03/29/1994 0930 Item 9 has Mr. William Hanson, briefing the Board on the policy to not use the shallow aquifer due to contamination. The Board approved this policy. Minutes approved by Thomas R. Case Brigadier General USAF Commander. The IRP has RODs for OUs 3 and 6 which require, the aquifer remain unused.
2) Personnel in the review process within CES must be aware of these policies and review them on a recurring basis. It is imperative this restriction be recognized and observed during engineer reviews and operations. |
Louis Howard |
| 12/31/1996 |
Update or Other Action |
Staff provided comments on the technical memorandum "SOP for Closing Bioventing Systems on the Glacial Outwash Plain at EAFB" dated November 14, 1996. Project managers from ADEC, the EPA, and EAFB agreed that attempting to develop a correlation between monitoring data and closure sampling would be beneficial. If a good correlation is shown to exist, then developing a closure procedure based on monitoring data should be possible. Since there has been extensive site investigation and monitoring work done on EAFB, this appears to be a reasonable alternative. It would reduce sampling costs associated with having to do subsurface soil confirmation sampling at every bioventing site in the outwash plain.
To decide whether this will be a feasible alternative, it will be necessary to identify the number of sites with various types of petroleum contamination; conduct bioventing system monitoring and respiration testing along with confirmation soil sampling at a representative number of the sites; and show a good correlation between the monitoring data and the soil sample results. To do this, ADEC requests a list be prepared showing the number of bioventing sites currently operating or proposed. The site list should be broken down into categories for gasoline range organics (GRO), diesel range organics (DRO), and residual range organics (RRO). ADEC requests 25% of the sites under each category, with a minimum of 10 from each be included in the confirmation soil sampling sites to decide if a good correlation can be developed. If less than 10 sites exist under any category (i.e. RRO) confirmation sampling should be done at each site in that category rather than pursuing an alternative closure process for them.
At Page 3, under "problem definition", it refers to relatively small volumes of contaminated soil commonly treated at the Base through bioventing. It states that once the obviously contaminated soil around an underground storage tank has been removed, the remaining contaminated soil is often in a relatively shallow and even layer. The basis for these statements is not clear. In many cases, when USTs were removed, contaminated soil was placed back into the ground. Since most outwash plain consists of coarse grained soil with a low organic carbon content, most of the releases have resulted in contaminate migration down to the groundwater.
Table #3 Footnote #1 refers to respiration testing between June 15 and September 30. It is likely that some frost may remain in the ground during June. Also, if sufficient biological activity is generated, the soil temperatures would remain elevated later into the year. Therefore, ADEC recommends respiration testing be conducted later in the year (i.e. between July 15 and November 15).
Figure 2 does not include fields for helium injection and monitoring during respiration tests. These should be included to evaluate whether short circuiting may be occurring. Average air flow rates at each venting well should also be reported. This may help indicate whether soil moisture may be a limiting factor due to drying of the soil during bioventing. The depth and screen length of soil implants should be provided on the form to simplify the review process. |
John Halverson |
| 6/16/1997 |
Update or Other Action |
USAF Memorandum to ADEC regarding Clarifications to OU2 ROD. The letter is a follow-up to the discussions regarding institutional controls at OU2. The USAF hopes by this correspondence, to clarify appropriate land use controls at OU2 and setup a land use restriction method consistent with the most recent Elmendorf RODs. The OU2 ROD states that groundwater at ST41 needs remedial action and a part of the selected remedy was to restrict land use by implementing zoning controls. The Summary of the ROD on page 9-2 states that the selected remedy includes "Zoning the affected area for industrial use only, excluding the development of commercial aquaculture."
However, the Declaration of the ROD states "Zoning the affected area for undeveloped outdoor/recreational use only." In light of this contradiction and the use of "restricted use areas" under the RODs for OU3 and OU6 the USAF is providing clarification of the permissible land uses within the area affected by ST41 groundwater. The affected area should include those areas that exceed the groundwater cleanup levels established in the OU2 ROD. A map of the area currently and potentially impacted by the contaminated groundwater from ST41 is at attachment 1. This map may be revised based upon review of the contamination remaining in place, which will be conducted at least every 5 years. While the affected area remains above cleanup levels, it will be designated as a "restricted use area" in the base Planning Office. This designation provides for recreational use of the parcel (such as cross country skiing, bicycling, etc.) and the construction of unmanned facilities (such as parking lots, storage buildings, etc.) but prohibits the construction of any manned facilities (such as office buildings or a residence). Construction activities within the affected area of OU2 will be restricted to construction of unmanned facilities. Furthermore, no construction will be allowed which comes within five feet of the groundwater. Existing industrial uses within OU2 are allowed as they are unmanned. This description conforms to the current base land use planning terminology and is consistent with the recently signed RODs for OUs 3 and 6. Land use restrictions will be enforced by the following method. When there is a construction project on Base, the project is to be approved by the Base Planning Office. The planner will route all projects through the Environmental Management Office. The project will be disapproved if it conflicts with the above construction restrictions. The USAF believes this will be a reliable and effective means of enforcing the zoning land use restrictions imposed by the various RODs. Signed by Randy E. Honnet Colonel USAF Vice Commander. |
Louis Howard |
| 10/6/1997 |
Update or Other Action |
Staff received addendum to the OU4 bioventing/soil intrinsic remediation monitoring report. Purpose of the addendum is to document the results of soil intrinsic remediation monitoring at Hangar 11 which were not available when the original monitoring report was written (July 1996). Hangar 11 SBSD25A sample was a reference used for 1994. 1996 results collected 30 feet from SBSD25A. DRO cleanup level is 2,000 mg/kg: 1994 5,900 mg/kg detected and 1996 153 mg/kg detected. GRO 1,000 mg/kg cleanup level: 4,100 mg/kg detected in 1994 and 1996 less than 5 mg/kg was detected. Because of limited contamination present, the difficulty in accessing the location for sampling, and the fact that the contamination present will be addressed under another program, it is recommended that the intrinsic remediation monitoring be discontinued under OU4 at this location. Active bioventing will change the rate of contamination decreasing, and this process would be more aptly addressed under the SERA VI monitoring program. |
Louis Howard |
| 1/13/1998 |
Document, Report, or Work plan Review - other |
ADEC provides comments to USAF regarding the Draft Soil Gas Report Number 4 and Semi-annual Monitoring Report OU4. The report recommends that bioventing operations be discontinued at sites FTA-1, FTA-2 and Hangar 11. ADEC concurs with recommendations and will require a closure plan with accompanying soil boring data showing cleanup has been attained below level "D" standards for each site. Additionally, if the data from the soil borings indicated those concentrations are above Level "D" standards, then additionally bioventing may be necessary. Finally, the report states the bioventing system at the Asphalt Drum Storage Area (SS10) be enhanced to increase biodegradation rates at the site. ADEC concurs. ADEC recommends further discussion among the OU4 RPMs to define what data needs to be collected and where the borings should be located for closing out the sites at FTA-1, FTA-2 and Hangar 11. |
Louis Howard |
| 7/24/1998 |
CERCLA ROD Periodic Review |
6/98 remedial action report (five-year review) states benzene, ethylbenzene, toluene impacted groundwater will be clean within 13 years. GRO/DRO contaminated soil will be clean in 1 year.
The May 1997 OU4 Bioventing Remediation Monitoring Report (Final) is the most recent report
summarizing the status ofbioventing remediation monitoring at OU4 sites. It includes the
presentation and evaluation of monitoring data collected from the start of the
bioventing/monitoring program in December 1995/January 1996 through December 1996. It also
includes data from soil borings drilled during an April 1997 LFI to further evaluate the progress of the remedial action.
Shallow Soils (Shallow Soils < 5 feet below ground surface; Deep Soils > 5 feet below ground surface)-For shallow soils, the report documented that sufficient intrinsic remediation has occurred such that cleanup goals have been reached at both soil intrinsic remediation sites, and no further monitoring of shallow soils should be necessary at these sites. The achievement of the cleanup goal was determined based on analysis of a composite of three soil samples selected to represent shallow soils in the vicinity of the original RI sampling location.
The O&M plan calls for soil sampling at the end of operations (at locations to be determined) for the following constituents: BTEX, GRO, DRO, moisture, pH, NOx, NH4, and, PO 4. Groundwater monitoring is performed semi-annually and results are evaluated annually as part of the Basewide Groundwater Monitoring Program.
No significant problems have been encountered. However, as discussed previously,
biodegradation rates developed using soil analytical data far exceed the theoretical degradation
rates developed using respiration testing and the AFCEE protocol for bioventing sites. This
suggests that remediation goals may be reached in less time than originally predicted in the ROD. The discrepancy between estimates is being evaluated; in the meantime operation of the
bioventing systems is continuing.
Remedy is operational and functional. ICs are in place and working as planned. The areas in OU4 which remain above cleanup goals will be subject to CERCLA five-year reviews until such time as cleanup goals are achieved. The OU4 five-year review(s) will be done as part of a Basewide review. Since the cleanup goals assumed residential use, once the cleanup goals are met, no further institutional controls or five-year reviews will be required for OU4. Next Five-Year Review is scheduled for completion by August 2003. |
Louis Howard |
| 11/4/1998 |
Meeting or Teleconference Held |
Restoration advisory board meeting held and announced beforehand in the Alaska Star 10/29/98, Sourdough Sentinel 10/30/98 and Anchorage Daily News on 11/1-3/98. |
Louis Howard |
| 1/29/1999 |
Update or Other Action |
Basewide Bioventing Annual Report received. The respiration test data indicated biodegradation rates of 186 mg/Kg/yr and 125 mg/Kg/yr at soil implants 5A and 5B, respectively. Soil implant 5C has consistently shown little or no indication of biodegradation activity.
The soil analytical data for this site indicates maximum GRO and DRO concentrations of 370 and 848 mg/Kg, respectively (Radian, 1994 and 1997). Because the soil analytical data has shown that sample concentrations do not exceed ACM level D cleanup criteria and current biodegradation rates are low, Bristol recommends discontinuing bioventing operations and attempting closure for this site. |
Louis Howard |
| 4/21/1999 |
Update or Other Action |
Directive number 9200.4-17P Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites, April 21, 1999 (Final).
Each OSWER program has developed regulations and policies to address the particular types of contaminants and facilities within its purview13. Although there are differences among these programs, they share several key principles that should generally be considered during selection of remedial measures, including:
• Source control measures should use treatment to address “principal threat” wastes (or products) wherever practicable, and engineering controls such as containment for waste (or products) that pose a relatively low long-term threat, or where treatment is impracticable.
• Contaminated groundwaters should be returned to “their beneficial uses wherever practicable, within a timeframe that is reasonable given the particular circumstances of the site.” When restoration of groundwater is not practicable, EPA “expects to prevent further migration of the plume, prevent exposure to the contaminated groundwater, and evaluate further risk reduction.”
• Contaminated soil should be remediated to achieve an acceptable level of risk to human and environmental receptors, and to prevent any transfer of contaminants to other media (e.g., surface or groundwater, air, sediments) that would result in an unacceptable risk or exceed required cleanup levels.
• Remedial actions in general should include opportunity(ies) for public involvement that serve to both educate interested parties and to solicit feedback concerning the decision making process.
Consideration or selection of MNA as a remedy or remedy component does not in any Way change or displace these (or other) remedy selection principles. Nor does use of MNA diminish EPA’s or the regulated party’s responsibility to achieve protectiveness or to satisfy long-term site remediation objectives. EPA expects that MNA will be an appropriate remediation method only where its use will be protective of human health and the environment and it will be capable of achieving site-specific remediation objectives within a timeframe that is reasonable compared to other alternatives. The effectiveness of MNA in both near-term and long-term timeframes should be demonstrated to EPA (or other overseeing regulatory authority) through: 1) sound technical analyses which provide confidence in natural attenuation’s ability to achieve remediation objectives; 2) performance monitoring; and 3) contingency (or backup)remedies where appropriate. In summary, use of MNA does not imply that EPA or the responsible parties are “walking away” from the cleanup or financial responsibility at a site.
It also should be emphasized that the selection of MNA as a remedy does not imply that active remediation measures are infeasible, or are “technically impracticable” from an engineering perspective. Technical impracticability (TI) determinations are used to justify a departure from cleanup levels that would otherwise be required at a Superfund site or RCRA facility based on the inability to achieve such cleanup levels using available remedial technologies. Such a TI determination does not imply that there will be no active remediation at the site, nor that MNA will be used at the site. Rather, such a TI determination simply indicates that the cleanup levels and objectives which would otherwise be required cannot practicably be attained using available remediation technologies.
In such cases, an alternative cleanup strategy that is fully protective of human health and the environment must be identified. Such an alternative strategy may still include engineered remediation components, such as recovery of free phase NAPLs and containment of residual contaminants, in addition to approaches intended to restore some portion of the contaminated groundwater to beneficial uses. Several remedial approaches could be appropriate to address the dissolved plume, one of which could be MNA under suitable conditions. However, the evaluation of natural attenuation processes and the decision to rely upon MNA for the dissolved plume should be distinct from the recognition that restoration of a portion of the plume is technically impracticable (i.e., MNA should not be viewed as a direct or presumptive outcome of a technical impracticability determination.) |
Jennifer Roberts |
| 7/12/1999 |
Document, Report, or Work plan Review - other |
Staff provided AF comments on the long-term Operations and Maintenance of the Base wide Bioventing systems at SD25 and FT23 dated May 1999. ADEC does not approve of data gathered from composite samples (except for metals and PCBs) or homogenizing of soil samples. ADEC requests UST Procedure manual be followed for field screening procedures and calibration of field screening instruments. |
Louis Howard |
| 11/8/1999 |
Update or Other Action |
The location of a former 500-gallon UST (tank 31-338) that was primarily used to store JP-4 jet fuel waste from fuel truck maintenance activities. The UST was removed in August 92, and replaced with a 1,200-gallon UST (31-338A) in an adjacent location.
The depth to groundwater in well 49WL01 located approximately 150 feet south-southwest of the site, was measured at 13.59 feet below ground surface (bgs). The depth to groundwater in the bioventing vent well was measured at 11.53 feet bgs. Shallow groundwater is not currently used as a drinking water source and is unlikely to be used as one in the future. Contaminant of concerns (COCs) with initial contamination levels are as follows:
Initial Contamination Levels for Soil Water
Diesel Range Organics (DRO) 860 mg/kg 9,700 ug/l
Gasoline Range Organics (GRO) 3,600 mg/kg 9,700 ug/l 9 Benzene .033 mg/kg 740 ug/l
Toluene 1.3 mg/kg 35 ug/l
Ethylbenzene 4.9 mg/kg 95 ug/l
Total xylenes 80 mg/kg 1,300 ug/l
STATEMENT OF BASIS-This decision is based on the following attached references:
a. Site ST71 from SERA Phase I Corrective Action Plan (CAP), Final, Apr 95
b. Alaska Department of Environmental Conservation's (ADEC) 27 Feb 97 Ltr
c. Table 4-17, Basewide Annual Groundwater Report, Final, Mar 98 (49WL01)
d. Site Closure Report for Site ST71, Nov 96 (refer to your copy)
e. Table 5-8, Basewide Annual Groundwater Report, Final, Jun 99 (49WL01)
f. Table 2-4, Basewide Monitoring OU4-Round 1, Aug 99 (49WL01)
DESCRIPTION OF THE SELECTED REMEDY-No further remedial action remedy is based on the field sampling conducted on 28 May 96 pursuant to closure of site ST71 on base. All of the laboratory analytical results for vadose zone soil were below ADEC (1995) Category A soil cleanup levels for all analytical methods. These results indicate that petroleum hydrocarbons in the vadose zone soil at the site have been remediated to the applicable matrix cleanup levels during the operation of the bioventing system.
Monitoring well 49WL01 has been added to the OPERABLE UNIT (OU)4 monitoring program. With the exception of benzene concentrations in groundwater at down gradient well 49WL01 (14.9 ug/l), GRO (930 mg/kg at 49BH07-12 and 500 mg/kg at 49BH08-13), and DRO (1,600 mg/kg at 49BH07-12) concentrations in saturated soil samples, this site meets all applicable state cleanup goals. Contaminated soil below the watertable is not effectively remediated through bioventing.
The vadose zone soil was below ADEC (1995) Category A soil cleanup levels for all analytical methods. This has allowed the bioventing system at this site to be turned off in 1997 and will be removed in the future. The groundwater contamination is under the cleanup levels in Table C using the criteria outlined by 18 AAC 75.345 (b)(2)(A)&(B). In addition, the wetland remediation system constructed on the Ship Creek flood plain prevents ST71 contamination from leaving the base property boundary. Therefore, there is no further requirement for tracking conditions at ST71. Monitoring well 49WL01 has been added to the OPERABLE UNIT (OU)4 (Basewide) monitoring program.
If any information is presented in the future that indicates contamination from this project area is present (above established cleanup levels) and/or poses a risk to the public's health or the environment, then additional assessment and corrective action may be necessary. The location of this monitoring well is useful to track trends of trichloroethene (TCE), dichloroethene (DCE), and chloride concentrations in the outwash plain. The remedy of no further remedial action under the ERP is selected because the contaminant levels at the site present no significant threat to human health or the environment; thus, no treatment is necessary. |
Louis Howard |
| 12/10/1999 |
Document, Report, or Work plan Review - other |
Staff reviewed draft site closure report for FT 23/SD 25. Benzene remains above cleanup levels in soil. Recommend that bioventing be continued until cleanup levels are achieved in approximately one year's time. Sampling will consist of a boring nearest SB 57 and 3 samples taken from boring. |
Louis Howard |
| 2/11/2000 |
Update or Other Action |
Staff reviewed and commented on the Draft Basewide Bioventing System, dated January 2000. DEC concurs with most of the recommendations for ST43/55. For negotiating cleanup levels
beyond the Level A criteria, DEC will consider adopting the cleanup criteria in 18 AAC 75. However, this move to a Method 2 cleanup level will require more analytical work on the Air
Force's part to show the site has achieved cleanup levels.
For the purposes of final closure sampling, the required minimum number of samples will be three per boring-at the area with the highest PID reading, at the highest historical contaminant level and
at soil/groundwater interface. Analysis of BTEX, DRO and GRO contaminants of concern (PAHs if following Method Two) will be required. |
Louis Howard |
| 4/10/2000 |
Update or Other Action |
1 January- 31 March 2000 quarterly report received. Results of closure sampling for FT23 and SD25 indicated that these sites did not meet the cleanup levels established in the OU4 ROD. Sites will continue bioventing for FY00. |
Louis Howard |
| 4/17/2000 |
Document, Report, or Work plan Review - other |
Staff reviewed and commented on draft Base wide Bioventing Systems Biweekly monitoring and soil gas respiration testing annual report. For the purposes of final closure sampling, the required minimum number of samples (from a minimum of three borings) will be three per boring at the area with the highest PID reading, at the highest historical contaminant level and at soil/groundwater interface. ADEC will require analysis of benzene, toluene, ethylbenzene, and total xylenes (BTEX), diesel range organics (DRO) and gasoline range organics (GRO) contaminants of concern (sampling for PAHs will be required if the Air Force chooses to cleanup under Method Two). Laboratory analyses, where applicable, will utilize approved AK lab methods, i.e. AK 101 and 102. |
Louis Howard |
| 2/21/2002 |
Document, Report, or Work plan Review - other |
Staff reviewed and commented on the base wide annual groundwater monitoring report.
Regulatory Levels
ADEC requests removing the word “Potential” from the heading “Potential Regulatory Level” in the tables throughout the document. Listing the word “Potential” gives the reader the impression that compliance with the levels listed is optional or not required (e.g. Tables 4-7, 4-11, 4-15, 4-20, 4-25, 4-29, 4-32, and 6-2).
Free Product-Please note 18 AAC 75.325(f) states: A responsible person shall to the maximum extent practicable,
(A) use permanent remedies;
(B) recover free product in a manner that minimizes the spread of contamination into an uncontaminated area by using containment, recovery, and disposal techniques appropriate to site conditions.
ADEC 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”.
Therefore, where free product is greater than 0.10 feet, ADEC expects corrective action (active or passive) to be implemented for free product recovery. Currently, free product was found to exceed 0.10 feet or more in SERA Phase I well 43-WL-11. This well had the highest level of free product measured at 0.86 feet. The presence of measurable free product is generally not considered conducive for intrinsic (natural) attenuation. ADEC requests the identity of the free product be described in the text at each source area that it is found (e.g. gasoline, diesel, or chlorinated solvents).
3.3.4 Target Analytes Pages 3-10 and 3-11
Benzene and TCE are identified as target analytes to evaluate contaminant of concern (COC) trends in detail and be consistent with the Base wide Groundwater model. ADEC concurs, however, focusing on these two analytes does not accurately reflect whether diesel range organics (DRO) and gasoline range organics (GRO) plumes are migrating, expanding, steady state, or receding (especially for wells noted to have either free product or fuel odor and/or sheen being observed during sampling). Benzene can be at low levels or even non-detectable while concentrations of DRO and GRO remain above cleanup levels (1.5 mg/L and 1.3 mg/L respectively). Please see the following examples below of where benzene was below the 5 ug/L cleanup level, but DRO and GRO are above cleanup levels.
OU 4
Round 1 sampling at well 49-WL-01 detected benzene at 0.11 ug/L and DRO at 2,400 ug/L and well OU4W-11 detected benzene at 4.3 ug/L while GRO was detected at 3,000 ug/L and DRO was detected at 6,100 ug/L.
OU6
Round 1 sampling at well OU6MW67 detected benzene at 2.8 ug/L, GRO at 2,500 ug/L and DRO at 1,700 ug/L during round 1 sampling. During round 2 sampling, well OU6MW-91 detected GRO at 25,000 ug/L and DRO at 9,500 ug/L while benzene was found to be non-detectable.
See site file for additional information. |
Louis Howard |
| 3/7/2002 |
Update or Other Action |
Staff reviewed and commented on the Base wide Bioventing report for 2001.
General Comments
Decommissioning Bioventing Systems
Where the Air Force is recommending bioventing systems be decommissioned, the Department requests additional clarification if the Air Force has looked at other alternatives to treat the "smear zone" (The smear zone is defined as the range of depths within which the groundwater will fluctuate under normal seasonal conditions, and therefore, in which free product would move and “smear” the soil in response to these seasonal changes in the water level elevation. The smear zone soils may therefore be saturated or unsaturated with groundwater at any given time.) contamination and found it was not practicable to implement them. The basis for not being practicable can be due to reasons such as: reliability of the alternative, alternative is not cost effective, site location, logistics in light of overall project purposes. If an analysis of alternatives was conducted, then it should be stated it is not practicable due to the incremental cost of implementing an alternative is substantial and disproportionate to the incremental degree of protection provided by the alternative as compared to another lower cost alternative.
Well Log Submittal
The Department also wishes to inform the Air Force of the well log recording requirement by the Alaska Department of Natural Resources (ADNR), Division of Mining, Land and Water. The requirement is referenced in the Underground Storage Tank (UST) Procedure Manual, Section 4.7.1 Installing groundwater monitoring wells. Alaska statutes: 38.05.020, 38.05.035, 41.08.020, 46.15.020 and regulations 11 AAC 93.140 require a log of the well be submitted to the ADNR within 45 days after installing a well.
The Department concurs with the recommendations in the document for SD25. |
Louis Howard |
| 5/21/2002 |
Update or Other Action |
Staff reviewed and commented on the draft monitoring and optimization work plan for base wide bioventing systems. The table states that if soils have been remediated to ADEC Method 2, Migration to Groundwater Pathway, Under 40-Inch Zone cleanup levels, bioventing should be shut off. The ADEC disagrees. At Section 4.2 of the work plan, it states that benzene was the only remaining constituent above the cleanup criteria established in the 1995 OU 4 Record of Decision (ROD). The ROD lists on page 4-3 Table 4-1 a cleanup level of 500 ug/kg or 0.5 mg/kg for benzene. The final cleanup level for SD25 will be the one specified in the OU 4 ROD at section 5.1.2 Applicable or Relevant and Appropriate Requirements (ARARs).
The ARARs section states “For petroleum contaminated soil that will be remediated, soil cleanup level D from the Alaska Cleanup Matrix, 18 Alaska Administrative Code (AAC) 78.315, is applicable.” Level D cleanup criteria at the time the OU 4 ROD was signed in 1995, consisted of the following: gasoline range organics-1,000 mg/kg, diesel range organics-2,000 mg/kg, sum of benzene, toluene, ethylbenzene, and total xylenes (BTEX)-100 mg/kg, and benzene-0.5 mg/kg. |
Louis Howard |
| 1/14/2003 |
Meeting or Teleconference Held |
Meeting minutes from January 14, 2003 meeting with Joe Williamson (USAF), Gary Fink (USAF), James Klasen (USAF), Kevin Oates (EPA), Louis Howard (ADEC), Cory Hinds (URS), Paul Dworian (URS), Kristin Paul (URS)
Discuss ADEC’s request to add the analyses of Diesel Range Organics (DRO) and Gasoline Range Organics (GRO) to several Operable Units at Elmendorf.
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 |
| 1/22/2003 |
Conditional Closure Approved |
Staff reviewed and commented on the draft SD25 Closure Report. Soils are closed but the groundwater (GW) is still being monitored because contamination in GW still exceeds cleanup level found in Table C of 18 AAC 75 for benzene. The Alaska Department of Environmental Conservation (the Department) has recently completed a review of the report delivered to our office on December 31, 2002. Based on our review of the information and analytical results provided by your consultant, the Department concurs with the conclusion that SD25 bioventing site soil sample results do not exceed the remedial goals established in the Operable Unit (OU) 4 Record of Decision (ROD). The Department, with concurrence by U.S. E.P.A., will determine that no further remedial action or sampling is required for this site.
The Department reserves all of its rights, under AS 46.03, 18 AAC 75, and 18 AAC 78 to require the Air Force to conduct additional site assessment, monitoring, remediation, and/or other necessary actions at SD25 located at OU 4 if information becomes available that contamination is found at this site which is poses a risk to human health or safety, welfare, or the environment. |
Louis Howard |
| 1/23/2003 |
Update or Other Action |
Letter from EPA RPM to Claude Mayer Air Force RPM RE: Draft SD 25 Closure Report December 2002. Elmendorf Air Force Base AK. EPA has the following recommendations based on this review.
1. The report documents that cleanup objectives for the deep soils identified in the September 1995 Record of Decision (ROD) for Operable Unit 4 have been achieved at SD-25. In the ROD this
area is identified as Hanger 11. The selected remedy in the ROD for this area included bioventing for the deep soils and intrinsic remediation (monitored natural attenuation) for the
shallow soils. The draft report does not discuss the results of sampling for the shallow soils. The report should discuss this aspect of the selected remedy in the introduction and discuss the results of shallow soil sampling.
2. Page 2-1. Under summary of past investigations contaminant source areas are identified. It would be beneficial to state that the source areas were removed prior to the 1995 ROD. |
Louis Howard |
| 1/29/2003 |
Update or Other Action |
Letter from ADEC RPM to Air Force RPM RE: Notice of No Further Action for Operable Unit 4 Source Area SD25 Facility ID No. 1525, Reckey No. 198821X933603
The Alaska Department of Environmental Conservation (the Department) has recently completed a review of the report delivered to our office on December 31, 2002. Based on our review of the information and analytical results provided by your consultant, the Department concurs with the conclusion that SD25 bioventing site soil sample results do not exceed the remedial goals established in the Operable Unit (OU) 4 Record of Decision (ROD).
The Department, with concurrence by United States Environmental Protection Agency (US EPA),
will determine,that no further remedial action or sampling is required for this site. The Department reserves all ofits rights, under AS 46.03, 18 AAC 75, and 18 AAC 78 to require the Air Force to conduct additional site assessment, monitoring, remediation, and/or other necessary actions at SD25 located at OU 4 if information becomes available that contamination is found at this site which is poses a risk to human health or safety, welfare, or the environment. |
Louis Howard |
| 2/25/2003 |
Update or Other Action |
Staff reviewed and commented on the Draft Bioventing Five-year Review of OU 4. At SD 25 the text does not list the description of the selected remedy as described in the record of decision as was the case for SD 25’s Five Year Review document recently submitted for review. The Department requests a description of the selected remedy for Operable Unit 4 be included in the text for the soil and groundwater. The five-year review of remedial actions taken at all operable units to ensure they remain protective of human health and the environment. Under CERCLA such reviews are required at least every five years after a record of decision is signed if contaminants remain in place. |
Louis Howard |
| 3/28/2003 |
Update or Other Action |
SD25 Closure Report received. This report has been prepared under contract No. F41624-00-D-8028, Task Order No. 0137, to document closure sampling activities at Site SD25 located on Elmendorf Air Force Base (AFB), Alaska. The remedy selected to treat surface soil contamination at OU 4 was intrinsic remediation, what is now known as monitored natural attenuation. The 1998 Five-Year Review Report states the “sufficient intrinsic remediation has occurred such that cleanup goals have been reached at SS10 and SD25 (Hangar 11).”
In 2002, closure sampling at SD25 consisted of drilling one soil boring (SB-57c) next to former
boring location SB-57. The boring locations are presented on Figure 2-3. One soil sample was collected from the 14 to 16-foot interval from this boring and submitted for laboratory analysis of total BTEX by Method SW8021B and GRO by Method AK101. GRO analysis was included in the analytical suite because GRO was detected at the cleanup level in the 14 - 16 feet bgs interval from soil boring SB-57 in 1999.
Results for GRO, benzene, and total BTEX in 2002 were significantly below levels identified during closure sampling conducted in 1999 and are well below remediation goals outlined in the OU 4 ROD.
Data gathered during the 1999 closure soil sampling event at SD25 indicated cleanup levels for
soils had been achieved for DRO, GRO, and BTEX; however, benzene slightly exceeded the 0.5 mg/Kg
closure criterion at the 14-16 feet bgs at SB-57. Based upon the estimated degradation rates calculated from the oxygen utilization measured during the respiration testing in 1999, it was estimated that remediation should be complete in one year (USAF, 2000).
In July of 2002, follow-on closure soil sampling was conducted to document that remediation
is complete at former boring location SB-57. One sample was collected at the interval of 14-16 feet bgs from boring SB-57c, installed adjacent to former boring location SB-57. Analytical results show that benzene levels were significantly less than levels in 1999, indicating that degradation of benzene has occurred to levels below remediation goals outlined in the OU 4 ROD. In addition, the GRO concentration has been remedia ted from the remediation goal concentration of 1,000 mg/Kg to 120 mg/Kg. Therefore, cleanup objectives for the deep soils identified in the September 1995 ROD for OU 4 have been achieved at SD25. |
Louis Howard |
| 1/27/2004 |
CERCLA ROD Periodic Review |
The second five year review was signed by ADEC. The purpose of this five-year review is to evaluate the implementation and performance of the remedial actions that were selected in the Record of Decision (ROD) for each Operable Unit (OU). Recommendations and follow-up actions: In OU4, close the bioventing system at SD25 because it has been documented that residential soil cleanup levels have been reached.
Recommendations and follow-up actions-In OU4, close bioventing at SD25 because it has been documented that residential soil cleanup levels have been reached. Soil cleanup levels are based on the Alaska Cleanup Matrix (ACM) level "D" for diesel range organics (DRO) at 2,000 mg/kg and GRO at 1,000 mg/kg.
The OU4 bioventing systems continue to operate and function as designed. Soil monitoring data shows that COC concentrations have decreased significantly over the five years that the bioventing systems have been in operation. Closure sampling at SD25 in 1999 and 2002 indicates that soil cleanup levels acceptable for residential use have been achieved and soil remediation at SD25 is complete. The trigger for this review was the signing of the first five-year review report on November 4, 1998. The next five-year review is in 2008. Groundwater cleanup levels are as follows: benzene at 5 ug/L, ethylbenzene at 700 ug/L and toluene at 1,000 ug/L. |
Louis Howard |
| 7/16/2004 |
Update or Other Action |
2003 Annual Technical Report Environmental Monitoring and System Optimization of base wide bioventing systems. Remediation is complete at SD25 so the system was to be removed. In October 2003, the bioventing system injection well and monitoring points at SD25 were dismantled. However, two of the monitoring points (BV 5B and BV 5C) could not be abandoned because a spoil pile from a large pipe excavation located immediately west of the injection well covered them. The spoil pile was not removed until after the drill rig had demobilized from the site. The monitoring points will be removed during the summer of 2004 when a drill rig is mobilized for work on base. The electrical power to the bioventing blower was disconnected in
February 2004 and the blower will be removed later in 2004 after snow melt. |
Louis Howard |
| 3/25/2005 |
Update or Other Action |
2004 Phase I RPO Annual Report (draft final) Groundwater Performance Optimization Monitoring Program received.
Hangar 10 - Although the OU 4 Record of Decision (ROD) predicts that this plume will achieve closure by 2008, the next round of sampling at the Hangar 10 Plume is not scheduled to occur until 2007. Because 1 year is deemed an inadequate response time to implement remedial action and ensure closure is achieved by 2008, it is recommended that the predicted cleanup date be reevaluated and the sampling frequency be increased to yearly.
The long-term monitoring plan for the Hangar 10 Plume should focus on monitoring benzene concentrations to verify this downward trend continues. To optimize performance monitoring at the Hangar 10 Plume, it is recommended that the following evaluations be performed:
Contaminant of Concern (COC) monitoring: COC monitoring for this plume is currently performed at one downgradient well. Monitoring network optimization and sampling frequencies should continue to be determined by using the decision guides in Appendix H.
Contaminant mass calculations: Contaminant mass calculations cannot be determined at this plume with any high degree of accuracy because Hangar 10 is a one-well plume. It is recommended that contaminant mass calculations not be performed at the Hangar 10 Plume.
Monitored natural attenuation (MNA) monitoring: It is recommended that MNA monitoring at the Hangar 10 Plume be discontinued. MNA assessments cannot be accurately performed at one-well plumes.
Cleanup date predictions: The OU 4 ROD allows remedial activities to proceed at this plume until the predicted cleanup date of 2008. It is recommended that SourceDK Tier 1 be used to generate a predicted cleanup date to compare with the ROD-specified cleanup date. Milestones should be established manually once this date is known.
Remedy protectiveness summary: MNA is the selected remedy at the Hangar 10 Plume. This remedy should be considered protective of human health and the environment. Although a predicted cleanup date does not exist, COC concentrations are decreasing, plume expansion is not occurring, and potential downgradient receptors are not being exposed to groundwater contaminants.
It is recommended that the COC monitoring network be reevaluated with existing decision guides during the summer of 2005. A revised cleanup date should also be predicted. Monitoring network optimization should be performed and the findings should be submitted as a stand-alone report before the 2005 Annual Report is prepared. The results of the reevaluation would not be generated in time to guide field activities during 2005, but would be available to influence recommendations in the 2005 Annual Report. |
Louis Howard |
| 3/26/2005 |
Update or Other Action |
HANGAR 11
2004 Phase I RPO Annual Report (draft final) Groundwater Performance Optimization Monitoring Program received. Since monitoring activities began at the replacement well, OU4MW-08R, these COC concentrations have shown a marked rise in contamination levels. It is recommended that the predicted cleanup date of 2008 be reevaluated, as opposed to increasing remedial activities at this plume. To optimize performance monitoring at this plume, it is recommended that the following evaluations be performed on the Hangar 11 Plume:
COC monitoring: COC monitoring for this plume is currently performed at one in-source well. Monitoring network optimization and sampling frequencies should continue to be determined by using the decision guides in Appendix H.
Contaminant mass calculations: Contaminant mass calculations cannot be determined at this plume with any high degree of accuracy because the Hangar 11 Plume is a one-well plume. It is recommended that contaminant mass calculations not be performed at the Hangar 11 Plume.
MNA monitoring: It is recommended that MNA monitoring at the Hangar 11 Plume be discontinued. MNA assessments cannot be accurately performed at one-well plumes. MNA monitoring in the future should entail monitoring COC concentrations to determine if these levels display a decreasing trend.
Cleanup date predictions: The OU 4 ROD predicts cleanup levels will be met at this plume by 2008. However, recent analytical results and a replacement well warrant a reevaluation of the cleanup date. Tier 1 of SourceDK is the recommended model for predicting a new cleanup date at a one-well plume such as Hangar 11. Milestones can be established manually once new cleanup goals have been created.
Remedy protectiveness summary: MNA is the selected remedy at the Hangar 11 Plume. This remedy should be considered protective of human health and the environment. Although a predicted cleanup date does not exist, plume expansion is not occurring and potential downgradient receptors are not being exposed to groundwater contaminants.
It is recommended that the COC monitoring network be reevaluated with existing decision guides during the summer of 2005. In addition, a revised cleanup date for the Hangar 11 Plume should be developed. These exercises should be performed and the findings should be submitted as a stand-alone report before the 2005 Annual Report is prepared. The results of the reevaluation would not be generated in time to guide field activities during 2005, but would be available to influence recommendations in the 2005 Annual Report. |
Louis Howard |
| 4/1/2005 |
Document, Report, or Work plan Review - other |
The Alaska Department of Environmental Conservation (ADEC) received the 2004 Phase I RPO Annual Report (Draft Final) Groundwater Performance Optimization Monitoring Program document on March 21, 2005. Below are ADEC’s comments on the document.
General Comments-Typically, delineating a plume of contaminated groundwater takes more than one well in the source area. ADEC requests the Air Force redraw boundaries for “plumes” in the following figures where one well is defining a “plume” of contaminated groundwater with a bold line and replace it with a dashed line to show it as being “inferred” or “interpreted” rather than a distinct boundary.
Zone 1
Figures 3.2-1 and 3.3-1 for wells: OU6MW-46 and OU6MW-63
Figure 3.3-3 for well OU6MW-46
Figures 3.5-1 and 3.6-1 for well ST41-10R
Figure 3.9-1 for wells: OU6MW-46 and OU6MW-63
Figure 3.10-1 for well OU6MW-46
Zone 2
Figure 4.1-1 for well 59WL-31
Figure 4.3-1 for well SP7/10-04
Figures 4.3-1 and 4.5-1 for well OU4MW-04
Figure 4.6-1 for well OU4MW-08R
Figure 4.7-1 for IS6-01
Figures 4.9-1 and 4.10-1 for wells: SP7/10-04 and W-4
Zone 3
Figure 5.3-1 for well OU3MW-25
Figure 5.5-1 for wells: 60WL-04 and 64WL-01
Figure 5.6-1 for wells: 64WL-01 and 62WL-05
Figure 5.10-11 for well LF59MW-03
3.2.4 Phase I RPO Conclusions and Recommendations
Verifying that plume expansion is occurring with one monitoring well is nearly impossible to do without additional monitoring wells. The text states that the OU6 ROD mandated 5-year reviews be performed to evaluate the performance of the selected remedy (MNA). However, the recommendation in this section for MNA monitoring states MNA assessments cannot be accurately performed at one-well plumes. Also the text states plume expansion is not occurring and potential downgradient receptors are not being exposed to groundwater contaminants. ADEC requests clarification on how it can be demonstrated with one monitoring well that downgradient receptors are not being exposed to groundwater contaminants and whether or not it can be shown a plume is expanding or shrinking when sampling data is limited to one well.
The comments above apply to: PL81 South Plume (Section 3.3.5), ST41 North Plume (Section 3.5.4), 59WL-31 (Section 4.1.5), Hangar 10 Plume (Section 4.5.4), Hangar 11 Plume (Section 4.6.4), OU4 East Plume (Section 4.7.5), SS43 Plum (Section 4.9.4), W4 Plume (Section 4.10.4), OU3MW-25 Plume (Section 5.3.4), and SP01-2 Plume (Section 5.8.4).
7.0 Phase I RPO Recommendations Summary Page 7-1
ADEC concurs with updating the conceptual site models for inclusion in the 2005 Program Baseline Calculations Report.
7.1 Plume-Specific Recommendations
ADEC concurs with the plume-specific recommendations listed in this section which are not provided in Table 7.1-1.
NOTE: Groundwater remains above 5 ug/L cleanup level established in the ROD for OU4 in well ID OU4MW-04. |
Louis Howard |
| 3/6/2006 |
Document, Report, or Work plan Review - other |
Staff reviewed the draft 2005 RPO Phase I report. The text states if significant downgradient migration were to occur, the contaminants found at SD25 would be detected at downgradient sites. ADEC requests the text include reference to exactly which specific sites are downgradient of SD25 that are monitoring these same COCs. The OU 4 ROD identified benzene, ethylbenzene, toluene, as the COCs in groundwater at SD25. Currently, the remaining COCs in the SD25 plume are benzene and toluene. |
Louis Howard |
| 3/7/2008 |
Update or Other Action |
Zone 2 Remedial Process Optimization Report received. The selected remedies for the Hangar 11 Plume are LUCs & monitored natural attenuation (USAF, 1995a). The monitoring well network in place at SD25 appears to be adequate to track reduction of contaminant concentrations. The single well does not appear to be appropriate to track migration of contamination downgradient. However, there are no potential human or ecological receptors immediately downgradient. LUCs are preventing human & environmental receptors from being exposed to contaminated groundwater.
The Hangar 11 Plume is a Red priority site because toluene concentrations remain elevated with no decreasing trend.
Replacement well OU4MW-08R is near the location of the former well OU4MW-08 & exhibits significantly greater COC concentrations. Review of boring logs associated with each well shows similar soil conditions in the water-bearing zone, with each boring having poorly sorted sand in the deeper intervals. The only difference noted was that some gravel was encountered in the lower portion of OU4MW-08; this is not expected to have a significant influence on the results.
The differences in COC concentrations between wells OU4MW-08 & OU4MW-08R during 1995 to 2002 may be explained by bioventing activity. Injection well BV-5 was located approximately 25 ft from OU4MW-08. Based on bioventing monitoring, the zone of influence of BV-5 would certainly encompass the area around OU4MW-08 (USAF, 1997). OU4MW-08 was screened from 15 ft to 40 ft, bgs leaving approximately 10 ft to 15 ft of screen above the water table. Air flow through the unsaturated zone from the bioventing system may have caused volatilization of contaminants from the water column in & around the well screen. If the bioventing system remained in operation
before & during the sampling events, the water sampled in the well may not have been representative. There is no record that groundwater sampling was preceded by shutting down the bioventing system for a few weeks to allow the system to return to static conditions, which may have allowed for more representative sampling in this area.
The high levels of toluene & benzene remaining at OU4MW-08R suggest that residual contamination from the source may remain in the subsurface. Review of historical soil boring/sampling results supports this conclusion. Soil boring SB57, completed as part of the bioventing closure efforts, has some of the highest benzene (up to 0.61 mg/kg) & toluene concentrations (up to 1.3 mg/kg) detected at SD25 (USAF, 2000). While these concentrations are below regulatory concerns for soils, they could indicate that a more significant source of contamination in this area is contributing to the persistent benzene & toluene concentrations being monitored in the groundwater. Direct push techniques to install temporary wells & collect groundwater samples could be used to better define the remaining magnitude & extent of residual contamination.
If significant residual contamination can be identified, it can potentially be addressed in situ to reduce the mass flux of contaminants into the groundwater system or to treat the groundwater near the source area. The use of targeted bioventing near the smear zone or biosparging just below the water table (or a combination of both) could enhance the degradation of these contaminants & get the remedy back on track.
An evaluation of the groundwater elevation gradients represented in previous reports was found to have a significant level of uncertainty for several reasons, which are further detailed in Section 8.4.1. These uncertainties make it difficult to interpret accurate groundwater flow directions & possible contaminant migration. Due to the lack of contaminant concentration trends & the undefined timeframe required to meet cleanup standards at this site, additional site characterization should be scheduled to address these uncertainties & help update the CSM.
The recommendations for the Hangar 11 Plume are as follows:
Short-Term (FY08-FY09)
• Continue monitoring per Figure 1.4.
Long-Term (FY10 or Longer)
• Continue monitoring per Figure 1.4.
• Perform field investigation to define the source area & downgradient contamination.
• Conduct source area removal or in-situ treatment.
• Perform RPO evaluation. Perform long-term monitoring optimization study & implement with approval from agencies.
• Monitor according to optimized monitoring schedule.
|
Louis Howard |
| 10/15/2008 |
Update or Other Action |
Bioventing systems were installed and activated at FT23, SS10, and SD25 in November 1995 (USAF, 1998b). Site locations are illustrated in Figure C-3 of Attachment C. The system at FT23 continues to operate as of 2008. Closure soil sampling conducted at SD25 in 2002 demonstrated that cleanup objectives were achieved for all soil contaminants. Based on these data, the SD25 bioventing system was shut down in 2003 (USAF, 2003b). Although SD25 soils meet cleanup levels, SD25 is still an open site due to the presence of contaminants in groundwater above the cleanup levels.
Natural attenuation appears to also be working at SD25, but the accidental abandonment of well OU4MW-08 after 2002 and installation of replacement well OU4MW-08R has complicated predictions for meeting cleanup goals.
During the period 2003 through 2007, there were several notable detections of contaminants at OU4 in addition to COCs:
In 2006, 1,1,2-trichloroethane, a COPC for OU4 groundwater, was detected in SD25 well OU4MW-08R at 39 µg/L and in FT23 well FP-56 at 19 µg/L. The MCL and ADEC cleanup level for 1,1,2-trichloroethane is 5 µg/L. 1,1,2-Trichloroethane had never been detected previously in OU4MW-08R, but was detected in well FP-56 in the 1990s. 1,1,2- Trichloroethane was not detected in any OU4 well in 2007.
Site Inspection
OU4 (SD24, SD25, SD28 and SD29). All active monitoring wells were located and were in good condition. There are no active monitoring wells for SD28. There was no evidence of unauthorized wells or site disturbance.
The cleanup levels for 1,2-dichloroethane, PCE, and TCE for FT23 groundwater, and DRO and GRO for SD24 and SD25 soil, as presented in OU4 ROD, are inconsistent with their referenced standards. The cleanup levels for 1,2-dichloroethane, PCE and TCE at FT23 are listed as 6 µg/L instead of the MCL standard of 5 µg/L. The cleanup levels identified for DRO and GRO at SD24 and SD25 are 1,000 and 2,000 mg/kg respectively, which is the reverse of their referenced ACM Level D standard. These inconsistencies appear to be typographical errors because there is no discussion in the ROD about deviation from the referenced standards. The cleanup levels for these COCs should be adjusted in a memorandum to the site file so they are consistent with the standards referenced in the ROD.
During the period between 2003 and 2007, there were two notable detections of contaminants in OU4 groundwater in addition to COCs. Bromomethane was detected at a very low concentration in one well at FT23 in 2005, but was not in any previous or subsequent samples. 1,1,2-Trichloroethane, an OU4 COPC, was detected at concentrations above the ADEC cleanup standard (there is no MCL for 1,1,2,2-tetrachloroethane) in one well each at FT23 and SD25 in 2006, but was not detected in 2007. The isolated detections are unlikely to represent new sources contamination at OU4.
The natural attenuation remedy is generally progressing as anticipated by the ROD, except at SD25. Natural attenuation is also occurring at SD25, but at a rate that is slower than originally anticipated in the ROD.
Issues
Inconsistent Cleanup Levels: The cleanup levels for 1,2-dichloroethane, PCE, and TCE for FT23 groundwater, and DRO and GRO for SD24 and SD25 soil, as presented in OU4 ROD, are
inconsistent with their referenced standards. The cleanup levels for 1,2-dichloroethane, PCE and TCE at FT23 are listed as 6 µg/L instead of the MCL standard of 5 µg/L. The cleanup levels
identified for DRO and GRO at SD24 and SD25 are 1,000 and 2,000 mg/kg respectively, which is the reverse of their referenced Alaska Cleanup Matrix Level D standard. These inconsistencies appear to be typographical errors because there is no discussion in the ROD about deviation from the referenced standards.
Cleanup Schedules: Monitoring shows that the natural attenuation remedies are generally decreasing COC concentrations. At several sites, the process is slower than anticipated in the ROD. For most of the affected sites, the slower attenuation rates are limited to a few individual wells or just a few additional years until cleanup goals are met. The slower rates of natural attenuation have the largest impact at OU5, where natural attenuation may take several
additional decades to reach cleanup levels. OU5 has a large monitoring program and a relatively expensive treatment system for contaminants discharging at seeps, so the impact on cleanup costs could be significant. In the interim, LUCs are in place to ensure protectiveness.
See site file for additional information.
|
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 |
| 4/5/2010 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 71411 name: auto-generated pm edit Elmendorf OU4 SD25 Hgrs 8, 10 & 11 |
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 - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil- Institutional controls on land use (also called LUCs) will continue to restrict access to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation - A land use control inspection was performed and land use controls are in place and continue to be effective at SD25.
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 |
| 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).
Currently there are ten active sites within the Zone 2 Management Area: FT23, SD15, SD24, SD25, SD28, SD29, SS43, ST32, ST48, & ST68. The OU4 ROD (USAF, 1995a) specifies the selected remedy for Sites FT23, SD24, SD25, SD28, & SD29. Currently, LUCs are used at all OU4 sites until cleanup levels are met, & GW monitoring is performed at Sites FT23 & SD25. At Site SD15, 149 an ESD; to the OU 6 ROD (USAF, 1997) transitioned the remedy for this site to monitored natural attenuation (MNA). The remedial approach for Site SS43 is described in the State-Elmendorf Environmental Restoration Agreement (SERA) Phase I Corrective Action Plan, & currently consists of natural attenuation with free product removal. The selected remedy for soils with contamination in excess of cleanup levels at Site ST32 is limited hot spot removal with off-site low-temperature thermal desorption.
A final remedy for GW at Sites ST32 & ST48 has not been established. The remedy for ST68 includes MNA & LUCs specified in a DD that was finalized in 2007. Impacted media at the Zone 2 Management Area sites includes soil & GW. COCs identified for Zone 2 sites include trichloroethene (TCE); tetrachloroethene (PCE); 1,1,1-trichloroethane (1,1,1-TCA); 1,1,2-TCA; 1,2-dichloroethane (1,2-DCA); 1,1-dichloroethene (1,1-DCE); 1,2-DCE; 1,1,2,2-tetrachloroethane (1,1,2,2-PCA); benzene, toluene, ethylbenzene, & total xylenes (BTEX); DRO; & gasoline-range organics (GRO).
The overall objectives of RA-O activities within the Zone 2 Management Area are to monitor the rate of natural attenuation within GW plumes, determine the effectiveness & protectiveness of the site remedies (currently MNA for all sites), & manage all waste according to state & federal regulations.
Site SD24 consists of one groundwater plume (OU4MW-04 Plume) in the central portion of Zone 2 north of the East/West Runway. The OU4MW-04 plume was formerly referred to as the Hangar 10 Plume. Hangar 10 (Building 15455) was used for fuel-loading operations, and potential sources of contamination identified in the RI/ Feasibility Study (FS) included an underground storage tank (UST) and pump house southwest of this building, and a petroleum, oils, and lubricants system near Hangar 10. However, uncertainties regarding the local groundwater flow direction in the vicinity of Site SD24 suggest that there may be a source area for this plume completely unrelated to Hangar 10.
The Zone 2 Management Area sites are located throughout the central portion of JBER-Elmendorf. The southern boundary of Zone 2 is parallel to the southern edge of the east/west instrument runway. The WP presents the site locations, associated sources, & plumes. Ten sites & 12 GW plumes are located within this management area, as follows (analytes shown exceeded cleanup levels during the most recent monitoring event):
• Site FT23 (2 plumes) - TCE & PCE
• Site SD15 - benzene & TCE
• Site SD24 - benzene
• Site SD25 - toluene & benzene
• Site SD28 - TCE & PCE
• Site SD 29 - TCE & PCE
• Site SS43 - benzene, gasoline range organics (GRO), DRO
• Site ST32 (2 plumes) - benzene, GRO, & DRO
• Site ST48 - GRO
• Site ST68 (2 plumes) - benzene & GRO |
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. 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.
OU4:
Site SD25
Groundwater - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil - Institutional controls on land use (also called LUCs) will continue to restrict access
to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation - LUCs are in place and continue to be effective at SD25. 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 |
| 4/10/2012 |
Update or Other Action |
Draft 2011 Zones 1, 2, & 3 report received.
SD025 (Hangar 11)
Concentrations of benzene (800 µg/L), ethylbenzene (1,500 µg/L), and toluene (12,000 µg/L) exceeded the groundwater cleanup levels of 5 µg/L, 700 µg/L, and 1,000 µg/L, respectively.
A LUC inspection conducted on 13 October 2011 did not identify any LUC issues at Site SD25. A groundwater monitoring well, 421MW-01, was installed for the CRP site ST424 within the Hangar 11 plume boundary during 2011.
The 2007 RPO evaluation identified Site SD25 as a Red priority site 3850 because toluene concentrations remained elevated with no decreasing trend (USAF, 2008g). Using monitoring data from 2003 through 2011, an increasing concentration trend is present for toluene and ethylbenzene at well OU4MW-08R (Figure 3.11). Concentrations of benzene show a decreasing trend over time, although concentrations measured in this well in 2010 and 2011 were higher than those measured in the previous three years.
Benzene concentrations are currently two orders of magnitude above the cleanup standard of 5 µg/L for this COC. Based on these data, the Red priority designation for SD25 remains appropriate.
Red sites are sites for which no cleanup date can be determined because of an increasing data trend. These sites have the highest priority in evaluating how to meet the program objectives. |
Louis Howard |
| 1/11/2013 |
Update or Other Action |
Draft UFP QAPP work plan received.
The overall objectives for the site are to meet “unrestricted or residential site use” criteria & achieve a “cleanup complete without institutional controls (ICs)” determination. To meet these objectives soil & GW samples will be collected to characterize risk to human health & the environment within the framework of the ADEC site cleanup process 18 AAC 75.325 to 390 & 18 AAC 78.600.
The light non-aqueous phase liquids (LNAPL) hydrocarbon contamination in the smear zone is the likely source of GW contamination at the site. Smear zone contamination will be treated using in-situ chemical oxidation (ISCO). Soil samples from the site characterization will be used to conduct a bench scale test to determine the most effective ISCO chemical & application method for this site.
Three borings will be installed to a depth of 15-feet bgs in the vicinity of the valve pits. The shallow vadose zone borings are intended to confirm that natural attenuation has successfully remediated near-surface soils (<14 feet). Deeper soils (14 ft bgs – 31 ft bgs) were previously characterized at the site & deep vadose zone soils were closed by the EPA & the ADEC. Samples from the soil boring cores will be collected & screened utilizing a PID. Based upon results of the PID field screening, the sample from each boring interval with the highest PID reading will be collected & submitted for laboratory analysis of GRO, DRO, RRO, & BTEX constituents. Additionally, one sample from within the upper zone of the source area will be submitted for lead (Pb), & ethylene dibromide (EDB).
The objectives of these borings are to delineate the extents of light non-aqueous phase liquid (LNAPL) hydrocarbon impact at the smear zone. The LNAPL smear zone contamination is the likely source contributing to down gradient impact in the GW. The area of the smear zone with LNAPL present will be the area where ISCO injections are focused in the future. The borings will start at the potential source & step out perpendicular to GW flow. The first step out will be approximately 20 ft., to one cross gradient side. The field screening results of the boring will determine the next step out length in the series of borings. Typical step-outs will be in 20 ft increments. However, larger step-outs may be used if high field screening results are found. This process will continue until clean samples are reached in each cross gradient direction. Once the lateral extent of the smear zone contamination is delineated, this process will be used to delineate the down gradient extent contamination.
Samples for lab analytical analysis will be collected from the area of smear zone contamination. Approximately three samples will be collected from the clean soils outside of the smear zone contaminated zone to confirm field screening results are accurate. All of the smear zone soil samples submitted for lab analysis of GRO, DRO, RRO, & BTEX constituents. One sample from within the source area will be submitted for lead, & EDB analysis.
One GW monitoring well will be installed down-gradient, immediately outside of the area of smear zone LNAPL contamination. The intent of this well is to be located in the saturated zone most impacted by the LNAPL contaminated smear zone. Two additional wells will be located cross gradient to the smear zone contamination on each side of the LNAPL plume. A fourth well will be installed up-gradient of the valve pits outside of the LNAPL source area. GW samples will be collected from the four new wells, along with a sample from OUMW-08R, & will be submitted for BTEX, GRO, DRO, RRO, extractable petroleum hydrocarbons (EPH), volatile petroleum hydrocarbons (VPH) & polycyclic aromatic hydrocarbons (PAH) analysis. The water sample from the down-gradient well will also be submitted for dissolved lead, & EDB analysis.
Soil samples from within the LNAPL contaminated smear zone will be collected to conduct a bench scale test to determine the most effective ISCO treatment option. Vadose zone soil samples from three representative boring locations will be submitted for grain size analysis to assist in ISCO design. ISCO treatment will likely consist of injection of either potassium permanganate or Regenox depending on bench scale test results. For the ISCO application, the active ingredient will be diluted to the appropriate concentration using clean tap water. The chemical will be injected in the subsurface through drill rod that is advanced using a direct push drill rig. |
Louis Howard |
| 1/25/2013 |
Document, Report, or Work plan Review - other |
EPA provided a cursory review of the draft UFP-QAPPs for SD025 and FT023 and requested additional information be provided for the UFP-QAPPs for the revised draft UFP-QAPPs.
EPA requires revision of the draft Site Characterization Workplan/ QAPP for SD025 and FT023, JBER, AK, January 2013.
EPA Region 10 conducted a cursory review of the both of the Draft Site Characterization Workplans/ QAPPs for SD025 and FT023, JBER, AK, January 2013. As stated in EPA General comment #5 on the draft Uniform Basewide Quality Assurance Performance Plan, all site-specifics workplans must complete the following worksheets and cannot reference the draft Uniform Basewide QAPP :
Worksheets #1 & 2 – Title and Approval Page
Worksheets #3 & #5 – Project Organization and QAPP Distribution
Worksheet # 6 – Communication Pathways, roles and responsibilities
Worksheet # 9 – Project Planning Session Summary
Worksheet # 10 – Conceptual Site Model
Worksheet # 12 – Measurement Performance Criteria
Worksheet #14/16 – Project Schedule
Worksheet # 15 – Project Action Limits and Lab Specific Detection/Quantitation Limits
Worksheet # 17 – Sampling Design and Rationale
Worksheet #18 – Sampling Locations and Methods
Worksheet #19 & 20 – Sample Containers, Preservation and Holding Times
Worksheet #20- Field QC Summary
Worksheet #23 – Analytical SOPs (if lab change)
Worksheet # 28 – Analytical Quality Control and Corrective Action (if lab change)
EPA requires a revised draft version of both workplans/QAPPs for review. Please ensure revisions are based on the changes agreed to at the JBER Basewide UFP-QAPP Comment Resolution meeting on December 20, 2012. The comments below are only based on a very cursory review and are not meant to be all-inclusive.
These workplans combine site characterization with a large scale treatability study and should state this directly. The worksheets incorrectly refer to the ISCO treatment as a remedial action, however ISCO is not a remedy identified in the OU4 rods for either of these sites. Approval by both EPA and ADEC will be required prior to initiation of the site characterization or treatability activities. EPA has been incorrectly designated as NA for approval signature for both workplans.
Worksheet #10 CSM should identify all possible routes of exposure, including vapor intrusion
The timing of the ISCO treatability study should be reflected in the project timelines and activities in worksheet #14/#16.
It is critical to understand if the current breakdown of TCE at FT023 is due to oxidizing or reducing conditions prior to conducting the ISCO treatability study. Addition of vinyl chloride to the target analyte list will provide valuable information on the stage of degradation.
For FT023, please describe how the presence of a building will impact the step in/step out characterization sampling for the smear zone.
As discussed during the JBER Basewide UFP-QAPP Comment Resolution meeting on December 20, 2012 (meeting minute # 3) EPA will not accept data for VOC soil samples preserved in methanol. Please clarify the methods used and sample numbers on worksheets #19/30 and #20.
For SD025, ADEC requested EDB to be added to the analyte list, however it is omitted in worksheets #15, #17, #18 and #20.
Both workplans provide incorrect references to well locations or figures. Worksheet #18 references Fig 2, possibly a mistake for Figure 1-2, however the locations of proposed monitoring wells is absent or difficult to distinguish from soil boring symbols. |
Louis Howard |
| 2/6/2013 |
Meeting or Teleconference Held |
EPA, JBER, CH2MHILL/WESTON PBR contractor, ADEC staff met to discuss basewide and site specific UFP-QAPPs (re: FT023 and SD025). It was agreed that the FT023 and SD025 plans would be resubmitted after incorporating comments received and revising the documents to only discuss characterization. The PMP (still draft form) refers to characterization plans, treatability plans and closure (via ESD, Memo to file or ROD amendment) documentation being submitted separately and they should not be anything else but site characterization work plans at this point in time for agency review. |
Louis Howard |
| 2/20/2013 |
Update or Other Action |
Resubmitted SC WP for SD025 draft dated February 2013 received.
Three borings will be installed to a depth of 15-feet bgs in the vicinity of the valve pits. The shallow vadose zone borings are intended to confirm that natural attenuation has successfully remediated near-surface soils (<14 feet). Deeper soils (14 ft bgs – 31 ft bgs) were previously characterized at the site & deep vadose zone soils were closed by the United States Environmental Protection Agency (USEPA) & the ADEC. Samples from the soil boring cores will be collected & screened utilizing a photoionization detector (PID).
Based upon results of the PID field screening, the sample from each boring interval with the highest PID reading will be collected & submitted for laboratory analysis of gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), & benzene, toluene, ethylbenzene, & xylene (BTEX) constituents. Additionally, one sample from within the upper zone of the source area will be submitted for lead, & ethylene dibromide (EDB).
A series of additional borings will be completed down to approximately 35 feet below ground surface in a grid pattern as shown on Figure 1-2. The objectives of these borings are to delineate the extents of LNAPL hydrocarbon impact at the smear zone. The LNAPL smear zone contamination is the likely source contributing to down gradient impact in the GW. The area of the smear zone with LNAPL present will be the area where ISCO injections are focused in the future. The borings will start at the potential source & step out perpendicular to GW flow. The first step out will be approximately 20 ft., to one cross gradient side.
The field screening results of the boring will determine the next step out length in the series of borings. Typical step-outs will be in 20 ft increments. However, larger step-outs may be used if high field screening results are found. This process will continue until clean samples are reached in each cross gradient direction. Once the lateral extent of the smear zone contamination is delineated, this process will be used to delineate the down gradient extent contamination.
Samples for laboratory analytical analysis will be collected from the area of smear zone contamination. Approximately three samples will be collected from the clean soils outside of the smear zone contaminated zone to confirm field screening results are accurate. All of the smear zone soil samples submitted for laboratory analysis of BTEX, GRO, DRO, RRO, & extractable petroleum hydrocarbons (EPH), volatile petroleum hydrocarbons (VPH), & polycyclic aromatic hydrocarbons (PAH) analysis. One sample from within the source area will be submitted for lead, & EDB analysis.
One GW monitoring well will be installed down-gradient, immediately outside of the area of smear zone LNAPL contamination. The intent of this well is to be located in the saturated zone most impacted by the LNAPL contaminated smear zone. Two additional wells will be located cross gradient to the smear zone contamination on each side of the LNAPL plume. A fourth well will be installed up-gradient of the valve pits outside of the LNAPL source area. GW samples will be collected from the four new wells, along with a sample from OUMW-08R, & will be submitted for BTEX, GRO, DRO, RRO, EPH, VPH, & PAH analysis. The water sample from the down-gradient well will also be submitted for dissolved lead, & EDB analysis.
Soil samples from within the LNAPL contaminated smear zone will be collected to conduct a bench scale test to determine the most effective ISCO treatment option. Vadose zone soil samples from three representative boring locations will be submitted for grain size analysis to assist in ISCO design.
Following the 2013 field activities a report will be generated summarizing the results of the site characterization and treatability study bench scale test. A work plan will following the report outlining the next step of the treatability study to be implemented in 2014. Based on the results of the bench scale test the next step will likely consist of an ISCO application consisting of the injection of either potassium permanganate or Regenox. |
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 and 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.
Groundwater - Restrict access to the contaminated groundwater throughout OU 4 until cleanup levels have been achieved. OU4 is designated "Airfield Use Area" for aircraft operations and maintenance, to include active and inactive runways, taxiways, and parking aprons for aircraft.
Soil-Institutional controls on land use (also called LUes) will continue to restrict access
to the contaminated shallow soils throughout OU 4 until cleanup levels have been achieved.
Evaluation -Inspection conducted on 26 Sep 12 and LUCs are in place and continue to be effective at SD25. |
Louis Howard |
| 3/5/2013 |
Document, Report, or Work plan Review - other |
Executive Summary
1st Paragraph
The text states: “Due to the close proximity of SD025 with site ST421, GW impact from both sites will likely be managed together.” No further explanation of ST421 is provided in the draft document regarding the USTs (425A 2,500 gallon mogas UST, 425B 3,000 gallon JP-4 UST, 425C 3000 gallon diesel UST, 425D 500 gallon diesel UST SERA Phase IV ST421 Release Investigation March 1997) or the contamination that is present in the soil or GW at ST421.
The 2011 GW monitoring result from well 421MW-01 detected GRO at 4,400 ug/L (Final 2011 Annual Report Monitoring of CRP Sites June 2012). ADEC has already provided comments on ST421’s UFP-QAPP on February 5, 2013.
3rd Paragraph
Please note that a cleanup complete without ICs will not be granted by ADEC to sites with vadose zone soils that exceed MAC for petroleum contamination for soil from 0 – 15’ bgs (i.e. direct contact for BTEX, PAHs &/or ingestion for DRO, GRO, & RRO) regardless of HRC calculated risk levels. Treatment or excavations deeper than 15’ bgs may be warranted on a site-specific basis to prevent the soil from acting as a continuing source of GW contamination.
Institutional controls or Land Use Controls shall be applied when (per July 27, 2012 meeting minutes on the “Use of Hydrocarbon Risk Calculator” with ADEC, JBER, PBR contractors):
• The GW under or downgradient of a site was contaminated with POL constituents at concentrations exceeding risk criteria or MCLs; or
• POL contaminants in the soil were above the MAC given in Table B2 of 18 AAC 75 or at concentrations exceeding risk criteria.
• ICs also needed if direct contact or inhalation risks exceed residential land use risk-based levels. Sites should be suitable for unlimited use/unrestricted exposure (UU/UE) for ADEC to grant a cleanup complete without ICs determination.
• In addition, sites with existing GW contamination above Table C cleanup levels will require that migration to GW cleanup levels be used for soil & ICs will be required.
Vadose zone soils shall not exceed MAC for petroleum contamination for soil from 0 – 15’ bgs (i.e. direct contact for BTEX, PAHs & ingestion for DRO, GRO, RRO) regardless of HRC calculated risk levels. Treatment or excavations deeper than 15’ bgs may be warranted on a site-specific basis to prevent the soil from acting as a continuing source of GW contamination.
In addition, sites with existing GW contamination above Table C cleanup levels will require that migration to GW cleanup levels be used for soil & ICs will be required. Once GW is below Table C for a period of time (per the latest approved “Basewide Monitoring Program Well Sampling Frequency Decision Guide (Attachment 1 Memo to the Site File for OUs 4, 5, & 6 September 2003)” two rounds annual GW monitoring), the MAC may become the cleanup levels as determined by ADEC on a case by case basis.
During the final round of monitoring, samples will be collected & analyzed for all constituents that are listed in the 1995 Record of Decision for Operable Unit 4 for source area SD025 (aka Hangar 11) at Table 5-2: benzene, ethylbenzene, toluene. These results will be evaluated by ADEC & EPA before a final determination is made that GW meets all CERCLA cleanup requirements. Also 18 AAC 75.325(g) states:
“If using method two or method three [e.g. HRC] for determining the applicable soil cleanup levels as described in 18 AAC 75.340 - 18 AAC 75.341, or if applying the GW cleanup levels at Table C in 18 AAC 75.345, a responsible person [JBER] shall ensure that, after completing site cleanup, the risk from hazardous substances does not exceed a cumulative carcinogenic risk standard of 1 in 100,000 across all exposure pathways & does not exceed a cumulative noncarcinogenic risk standard at a hazard index of one across all exposure pathways. Guidance on cumulative risk determinations is provided in the ADEC's Cumulative Risk Guidance, dated June 9, 2008. The Cumulative Risk Guidance, dated June 9, 2008, is adopted by reference.”
The Air Force shall demonstrate compliance with 18 AAC 75.325(g) in all of its decision documents (e.g. cleanup complete without ICs, cleanup complete with ICs for PBR & non-PBR sites).
Please note that during the 1994 Remedial Investigation, SD25 (Hangar 11) GW contamination maximum detections were noted as follows:
Table 4-53 Summary of Organic Results for Hangar 10/11 Plume Area GW Samples
Benzene 2,600 ug/L (OU4W-8) (Table C 5 ug/L)
Toluene 5,590 ug/L (OU4W-8) (Table C 1,000 ug/L)
Ethylbenzene at 1,360 ug/L (OU4W-8) (Table C 700 ug/L)
Chlorobenzene at 190 ug/L (Table C 100 ug/L) (SB-34 from Table 4-52 Summary of GW Screening Results from the Hangar 11 Plume Area)
Unknown compounds within Jet Fuel Range 10.8 mg/L (OU4W-8) (no comparable Table C cleanup level.)
Unknown compounds within Gasoline Range 49.2 mg/L (OU4W-8) (Table C GRO 2.2 mg/L) |
Louis Howard |
| 3/21/2013 |
Document, Report, or Work plan Review - other |
EPA (Sandra Halstead) provided review comments on the SC Work Plan.
ES p. ES-1 Third Paragraph. Please reference the Elmendorf FFA and CERCLA as a framework for work conducted under the site cleanup process in addition to ADEC guidelines.
ES p. ES-1 Fourth Paragraph. Soil samples will be used to conduct the bench scale test to determine the most ISCO chemical and application method for the site. EPA recommends that additional factors, including groundwater geochemical conditions, be considered when designing the bench scale test for future treatment options.
W #5 p. 11-12 As this is the site specific QAPP, the introductory sentence here does not make any sense and should be omitted.
The regulatory agencies (USEPA and ADEC) are absent from this flow chart. Only logos and no contact names are provided for the Air Force contacts. From the U-QAPP guidance, worksheet #3 & #5, "This worksheet identifies key project personnel, as well as lines of authority and lines of communication among the lead agency, prime contractor, subcontractors, and regulatory agencies.... Use asterisks or other symbol to designate QAPP recipients."
W #11 p. 19-20 The problem statement focuses on meeting ADEC risk criteria related to petroleum releases, however the exceedances of BTE in groundwater require CERCLA risk criteria to be met.
The Information inputs section suggests previous site specific groundwater data is available. Please describe this information in worksheet #10.
Spatial boundaries of the study as shown on Figure 1-2 poorly portray potential horizontal/lateral boundaries. With 4 borings ( E, SE, SW, W) as proposed from the source of contamination as described in Worksheet #17 Sampling Design, on 20 foot step-out intervals as described on page ES-3, it appears the lateral extent of the soil borings would not exceed 800 ft2. The 9 borings illustrated on Figure 1-2 suggest at least 3600 ft2. If borings are drilled to 35 ft depth as described on page ES-3, the 4 borings will only cover 20% the volume of soil as Figure 1-2 suggests. As no proposed groundwater wells are shown on Figure 1-2, it is impossible to estimate both the horizontal and vertical boundaries of the groundwater site characterization work.
p. 20 first paragraph discusses how ADEC “soil and groundwater cleanup levels will be used to assess laboratory dectection limits”. Laboratory dectection limits are established independently of any cleanup level; however laboratory detection limits relative to cleanup levels must be assessed to determine adequate analytical capacity of the lab. Please clarify this section of worksheet #11 of this workplan. JBER will need to assess the capability of their labs and ensure the Reporting Limits will meet the specified cleanup levels, especially for 1,2-dibromoethane (EDB) in groundwater.
The data quality objectives are very terse, and do not match the DQOs provided in the JBER Basewide UFP-QAPP. For example, this workplan lists DQO1 as determine the nature and extent of contamination in soil and groundwater. In the JBER Basewide UFP-QAPP, the parameters associated with nature and extent are listed under DQO2, and only encompass soil.
|
Louis Howard |
| 5/30/2013 |
Update or Other Action |
Draft Annual Field Activities report received for review & comment.
This report summarizes the 2012 annual long-term management activities, including remedial action-operation (RA-O) & Record of Decision (ROD) requirements conducted at Joint Base Elmendorf-Richardson (JBER) Comprehensive Environmental Response, Compensation, & Liability Act (CERCLA) sites. The United States Air Force (USAF) has mandated a reduction of long-term environmental liabilities & life-cycle costs through accelerated cleanup of contaminated sites.
As such, the Performance Based Remediation (PBR) initiative has been developed to protect human health & 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 & related activities at several JBER contaminated sites. The contract includes performing RA-O & ROD requirements at those sites. The WESTON Team performing the activities summarized in this report consists of WESTON & 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).
During 2012, groundwater monitoring well OU4MW-08R was sampled for VOCs and well 421MW-01 was sampled for BTEX only. Concentrations of benzene (610 µg/L), ethylbenzene (1,600 µg/L), and toluene (31,000 µg/L) exceeded OU4 ROD cleanup criteria for well OU4MW-08R.
During 2011, groundwater monitoring well 421MW-01 was installed for ST424 within the Hangar 11 plume boundary and is included here since it marks the southern plume boundary of SD025. No contaminants exceeded cleanup criterion in well, 421MW-01. Table 10-1 presents a summary of the results. Historic results are presented on Figure 10-1 A LUC inspection performed at SD025 on 26 September 2012 did not identify any issues at the site.
Site Summary
Analytical laboratory results have remained above cleanup criteria for all COCs since 2003 in
well OU4MW-08R. Down gradient well 421MW-01 concentrations for all COCs were below cleanup criteria indicating that the plume is not migrating. Using monitoring data from 2003 through 2012, an increasing concentration trend is present for toluene and ethylbenzene at well
OU4MW-08R. Concentrations of benzene show a decreasing trend over time, although concentrations measured in this well during 2010 and 2011 were higher than those measured in the previous three years.
An additional investigation to characterize soil and groundwater contamination is planned for
SD025 in 2013 under the new PBR contract. No changes to the annual monitoring are being proposed for this site. |
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.
The U. S. Environmental Protection Agency Region 10 has reviewed the Fourth CERCLA Five-Year Review report for Superfund sites, specifically for Operable Units (OU) 1, 2, 4, 5, 6 and DP98 associated with Elmendorf Air Force Base on Joint Base Elmendorf-Richardson, Alaska. The conclusions in this letter are based on the draft report from November 2013 and revised Response to Comments, Summary Form, and Sections 8 and 9 which were received by the EPA on March 12, 2014.
The EPA reviewed the report for technical adequacy, accuracy, and consistency with the National Contingency Plan and EPA guidance. The document provides a summary of the status and protectiveness for OUs for which Records of Decisions (RODs) have been completed and are not determined as No Further Action. It also identifies actions to be taken that ensure protectiveness of the selected remedies and on-going remedial actions and documents a schedule for completion of the recommended actions.
The following are the EPA’s protectiveness determinations for these OUs and the overall Site protectiveness that will be reported to Congress in the EPA’s annual report. 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. In general, the EPA concurs with the protectiveness determinations in this Air Force report. Each OU is discussed individually below.
OU 4
The EPA concurs with the deferred protectiveness determination for OU 4 pending additional sampling to address the potential for vapor intrusion at occupied buildings in proximity to the contaminated chlorinated groundwater plumes. The vapor intrusion evaluation will prioritize buildings with the most vulnerable populations (child care centers, schools, homes or offices occupied by women of childbearing age) and is expected to be completed for all occupied facilities by 2015.
In addition, benzene contaminated groundwater at Site SD25 remains at least one order of magnitude above cleanup levels and exceeded the predicted cleanup date of 2008. Land Use Controls for OU4 prohibit access to contaminated groundwater as a source of drinking water. EPA agrees with the recommendation to evaluate alternative remedies using the process established in the FFA to accelerate attainment of cleanup levels in groundwater at SD25.
An addendum to determine the protectiveness of OU 4 will be prepared by December 31, 2016.
|
Louis Howard |
| 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.
A LUC inspection was performed at SD025 on 24 September 2013 and did not identify any issues
at the site.
Analytical laboratory results were above cleanup criteria for all COCs from 2003 through 2012 in well OU4MW-08R. During 2013, concentrations of all three COCs in the well were below OU4 ROD cleanup criteria, which is inconsistent with previous rounds of sampling. Contaminant concentration trends in well OU4MW-08R are shown on Figure 10-2. Mann-Kendall trend tests show that there is a statistically significant increasing trend at the 95% level of significance in the well for ethylbenzene. The Mann-Kendall trend tests show that there is not a statistically significant increasing or decreasing trend at the 95% level of significance for benzene or toluene. |
Louis Howard |
| 6/4/2014 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft CERCLA GW report.
See comments regarding ICs adequacy being reported as N/A and dig permits issued within the last 12 months.
The Site Inspection Checklist should refer reader to photo 26 for SD025 in the Comments section as was done for FT023 and DP098 previously. Also add recommendations for future annual LUC inspection in 2014 (e.g. September 2014).
Sample results for the first time are below Table C in OU4MW-08R. Toluene went from 31,000 ug/L in 2012 to 170 ug/L, Benzene went from 630 ug/L in 2012 to ND (2.0 ug/L) and Ethylbenzene went from 1,600 mg/L in 2012 to 96 ug/L. ADEC requests clarification on the big decrease in contaminant levels from August 13, 2012 to September 27, 2013. Please provide details on the sampling depth in well, groundwater levels in the well, sampling equipment used at OU4MW-08R during the 2013 field season. This appears to be an anomalous reading based on the historical sampling from October 2003 to August 2012. A sample result below Table C in 2015 will not grant closure or cease groundwater monitoring for SD025. This site will need additional groundwater monitoring beyond 2015.
|
Louis Howard |
| 11/5/2014 |
Document, Report, or Work plan Review - other |
EPA provided comments on the draft CERCLA report.
Comment: Why aren't the activities and results of the SD025 site characterization in 2013 included in this report?
Comment: Please clarify why 2013 sample results for SD025 were not included in trend analysis. The 2013 results for OU4MW-08R were inconsistent with previous sampling rounds and additional analysis should be conducted and explanation must be provided in the narrative to explain the discrepancy.
Comment: See earlier comments on how to handle outliers in trend data, and the previous comment on the need for additional analysis for the order of magnitude difference in sample results from 2012 to 2013. Provide a footnote on why 2013 data is not included on Figure 10-2. |
Louis Howard |
| 7/23/2015 |
Update or Other Action |
Draft Annual Field Activities report received for review and comment.
SITE SUMMARY AND RECOMMENDATIONS
In 2013, site characterization activities outside of annual LTM activities were conducted at the
SD025 site to evaluate potential risks to human health and the environment in order to advance
towards site closure. Results and recommendations from this report are presented in the SD025
Site Characterization Report.
Five-Year Review
Areas in OU 4 that remain above cleanup goals are 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 and performance of the remedial actions. There were no
recommendations for SD025 documented during the first five-year review period. The second five-year report recommended decommissioning and closure of the bioventing system at the site because residential soil cleanup levels had been reached.
The third five-year review report recommended updating DRO and GRO groundwater cleanup levels to be consistent with the referenced standards and use of trend analysis in order to evaluate the remedy and revise estimated dates for achieving cleanup levels. The fourth five-year review report recommended evaluation of alternative remedial strategies to accelerate the attainment of cleanup levels in groundwater and conduct a vapor intrusion evaluation for each occupied facility that is in proximity to the plume.
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
Site SD025 is identified as a Yellow priority because site COCs are above cleanup levels. There
are no recommended changes to the current LTM approach for this site. |
Louis Howard |
| 6/14/2016 |
Update or Other Action |
Draft SC Report received for review and comment.
The site characterization was conducted to determine:
· the source of elevated concentrations of dissolved hydrocarbons in groundwater detected in monitoring well OU4MW-08R;
· the vertical and horizontal extents of residual hydrocarbon in soil and the areal extent of
groundwater contamination; and
· an approach to support SD at SD025.
This report presents the results of the 2013 and 2014 site characterization activities, as well as
results from previous investigations, to characterize the nature and extent of residual petroleum
hydrocarbon contamination in the soil and groundwater. In addition, this report evaluates the
exposure pathways that could present a potential risk to human health and the environment. Soil
and groundwater contaminant concentrations in this report are compared to the criteria provided
in 18 AAC 75 Oil and Other Hazardous Substances Pollution Control.
Based on the shallow depth and “tar-like” appearance of this contamination, it appears unrelated to the petroleum contamination found at deeper depths onsite specifically in the area of 13SD025-SB08. The lateral extent of this shallow contamination was not delineated during this investigation. However, the concentrations of GRO and DRO were below the soil cleanup level (under 40-inch zone) for the ingestion and inhalation pathways. These two shallow locations contained GRO and DRO at concentrations above the migration to groundwater cleanup levels. However, these risk criteria are not relevant to the site due to the existing IC, which prevents a complete groundwater ingestion pathway for current and future personnel onsite.
Results suggest that the bioventing system was effective at removing most of the mass of
contamination above the water table. Results from the ADEC Method Three risk evaluation
indicate that, based on the concentrations of constituents in the deep soil (5-20 feet bgs), direct contact with the soil is acceptable for unrestricted use. These findings support the 2008 five-year review recommendation for no further action for soil at SD025. Risk evaluation was not performed on soil samples collected from deeper than 20 feet bgs, as their depth precludes direct contact and site groundwater samples indicate that the shallow groundwater is below ADEC groundwater cleanup levels, with the exception of the area immediately around OU4MW-08R.
Except for GRO, constituents in all groundwater samples collected during the 2013 sampling
events were below their respective 18 AAC 75 Table C cleanup levels. The 2014 results indicate
dissolved phase GRO, DRO, benzene and toluene concentrations above 18 AAC 75 Table C
cleanup levels. The areal extent of the impacted groundwater appears to be limited to the area
surrounding OU4MW-08R, as the four other wells sampled were all below ADEC groundwater
cleanup levels.
See site file for additional information.
|
Louis Howard |
| 7/1/2016 |
Document, Report, or Work plan Review - other |
Staff reviewed the draft SC report.
ADEC considers the vapor intrusion pathway potentially complete when contamination is above cleanup levels within 0-30 ft. bgs. This issue will need to be addressed once and ESD is signed.
A vapor intrusion assessment will be required for SD025, once an ESD is signed, since 1-Methylnaphthalene and 2-Methylnaphthalene are considered volatile contaminants and were detected at 16.0-16.5 ft. bgs above cleanup levels (15 mg/kg and 19 mg/kg, respectively in sample # 13SD025-SB08-16.0-16.5-0).
the Final UFP-QAPP work plan approved for the investigation at SD025 focused mainly on ROD contaminants of concern (e.g. DRO/GRO soil) and did not test for PAHs in the 0-15’ soil interval (i.e. “shallow” soils) and therefore this is a data gap under State of Alaska regulations. The ROD COCs for OU4 will no longer be the sole contaminants for SD025 once the explanation for significant differences is signed. PAHs in soil for 0-15’ bgs appears to be a data gap especially with 1-methylnaphthalene and 2-methylnaphthalene above migration to groundwater cleanup levels in the 15-30’ bgs interval (16-16.5’) and will need to be addressed once an ESD is signed.
Be aware that once groundwater is contaminated above Table C (e.g. benzene, toluene, GRO, DRO), cleanup levels for all contaminants default to migration to groundwater cleanup levels at all depths until such time that two annual rounds of groundwater monitoring show that Table C cleanup levels have been met. This issue will need to be addressed further once the ESD is signed.
Unless a risk assessment under Method Four under State regulations (18 AAC 75) is conducted with a pre-approved work plan conducted in accordance with ADEC’s Risk Assessment Procedure Manual and the subsequent risk assessment reviewed and approved by ADEC. Method Three calculator or Method Three Hydrocarbon Risk calculator does not change the Table C groundwater cleanup level requirements in 18 AAC 75.
See site file for additional information. |
Louis Howard |
| 11/3/2016 |
Update or Other Action |
Draft Explanation of Significant Differences (ESD) received for review & comment.
This ESD has been prepared to change the governing regulatory authority & the applicable environmental regulations for implementing remediation at SD025. Specifically, the status of the site changes from remedial action implementation to No Further Action (NFA) under the Comprehensive Environmental Response Compensation & Liability Act (CERCLA, 1980) in order to allow future remediation to be managed under 18 Alaska Administrative Code (AAC) 75 (Oil & Other Hazardous Substances Pollution Control), 18 AAC 78 (Underground Storage Tanks), & supporting State of Alaska guidance documents.
This regulatory action is warranted because the contaminants of concern (COCs) for SD025 are either petroleum hydrocarbon compounds or are derived from petroleum hydrocarbon compounds, which are excluded substances under CERCLA §101(14). No CERCLA COCs were identified for SD025.
See site file for additional information. |
Louis Howard |
| 11/30/2016 |
Document, Report, or Work plan Review - other |
Staff provided comments on the Draft ESD for SD025 to move it from CERCLA to ADEC oversight since the COCs are petroleum related.
Main comments were regarding the use and reference of the most current regulations for CS and LUST.
See site file for additional information. |
Louis Howard |
| 1/13/2017 |
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 SD025 is identified as a Yellow priority because site COCs are above cleanup goals. There
are no recommended changes to the current LTM approach for this site. The site priority and
recommendations will be updated once the SD025 – Bldg 16430 Floor Drains Site
Characterization Report is final.
See site file for additional information. |
Louis Howard |
| 1/23/2018 |
Update or Other Action |
Final Explanation of Significant Differences (ESD) received. It has been prepared to change the governing regulatory authority & the applicable environmental regulations for implementing remediation at SD025. Specifically, the status of the site changes from remedial action implementation to No Further Action (NFA) under the Comprehensive Environmental Response Compensation & Liability Act (CERCLA, 1980) in order to allow future remediation to be managed under 18 Alaska Administrative Code (AAC) 75 (Oil & Other Hazardous Substances Pollution Control) revised as of November 6, 2016, 18 AAC 78 (Underground Storage Tanks, amended as of December 3, 2016), & supporting State of Alaska guidance documents. This regulatory action is warranted because the contaminants of concern (COCs) for SD025 are either petroleum hydrocarbon compounds or are derived from petroleum hydrocarbon compounds, which are excluded substances under CERCLA §101(14). No CERCLA COCs that are not naturally present in petroleum were identified for SD025.
See site file for additional information. |
Louis Howard |
| 2/9/2018 |
Document, Report, or Work plan Review - other |
Staff reviewed and commented on the draft Annual Report for CERCLA sites. Main comments were to request that DRO, GRO and PAHs be analyzed for in groundwater at Hangar 11 (aka SD025 OU4) under State regulatory requirements in accordance with the 2003 meeting minutes and 2010 Air Force memorandum regarding these COCs for fuel sources being monitored under CERCLA. A review of the 2004-2015 groundwater monitoring reports show no analyses for DRO or GRO at SD025. If DRO, GRO, or PAHs are above current cleanup levels for groundwater, ADEC will require that they be analyzed for as part of the long-term monitoring at SD025.
ADEC requests from this point forward that all groundwater be tested for PFOS at SD025. PFOS was detected in groundwater at concentrations above the EPA Health Advisory, but below the ADEC cleanup level at Hangar 8 (2017 Site Inspection for AFFF Areas). PFOS was detected in soil at a concentration below the EPA RBSL and ADEC cleanup levels. At Hangar 10, PFOA was detected at a concentration below the EPA RBSL and ADEC cleanup levels. PFOS was not detected in soils. However, PFOS and PFOA were detected at concentrations above the EPA Health Advisory but below the ADEC groundwater cleanup level.
See site file for additional information. |
Louis Howard |
| 9/19/2019 |
Document, Report, or Work plan Review - other |
Staff commented on the 2019 RA/LUC/IC WP. Main comment: Test all IDW (soil and groundwater) for PFOA and PFOS prior to disposal.
SD025: This source area is directly downgradient from a known groundwater PFOA/PFOS contaminated source area: AFFF Area #24 Hangar 18 Bldg. 17470.
See site file for additional information. |
Louis Howard |
| 2/7/2023 |
Document, Report, or Work plan Review - other |
DEC reviewed 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 |
| 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 |
| 4/25/2023 |
Document, Report, or Work plan Review - other |
DEC approved the 2023 Letter Work Plan Remedial Action Operations and Long-Term Management, Final, Dated April 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 |
| 1/30/2025 |
Document, Report, or Work plan Review - other |
DEC approved the 2025 Remedial Action–Operations and Long-term Monitoring Work Plan Addendum Final, dated January 2024.The work plan describes the site inspections, maintenance activities, and groundwater, seep, and surface water monitoring, activities that will be conducted at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. The scope of work briefly summarizes the site locations, sampling/monitoring activities and schedules. This workplan will remain consistent with the procedures outlined in the 2023 Letter Work Plan Remedial Action-Operations and Long-Term Management. |
Ginna Quesada |
