| Action Date |
Action |
Description |
DEC Staff |
| 9/1/1983 |
Update or Other Action |
IRP Phase I Records Search (Contract No. F08637-83-G0009, Call No. 5003,). PCB transformers were stored at Site S-6, the old ITT, facility during the 1970's. No significant spillage of transformer oil is known to exist at this location. However, due to the large quantity of PCB transformers stored at this location a potential for contamination is probable, leakage may have occurred.
See site file for additional information. |
Louis Howard |
| 8/2/1988 |
Update or Other Action |
Operable Units' source areas that correspond to RCRA SWMUs from the RCRA RFA. SS21 S-6 PCB Transformer Storage Area. Located north Juniper Drive and east of Loop Road, encompassing Bld. 31-357. Old ITT site used to store PCB transformers in the 1970's. This site has low potential
for environmental contamination, however a study shall determined the extent of contamination and the pathways affected to include soil sampling and analysis for the presence of *PCB's.
NOTE TO FILE: *PCBs belong to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCBs were domestically manufactured from 1929 until their manufacture was banned in 1979. Aroclors 1016, 1242, 1254, and 1260 are complex mixtures of polychlorinated biphenyl (PCB) congeners, prepared by the chlorination of biphenyl. For Aroclors 1242, 1254, and 1260, the chlorination reaction was stopped when the weight percent chlorine of the product had reached 42, 54, or 60%, respectively. By contrast, Aroclor 1016 was prepared by the fractional distillation of Aroclor 1242, which excluded the higher boiling (i.e., more highly chlorinated) congeners. Aroclors 1016, 1242, 1254, and 1260 were the most widely used PCBs in the United States, and accounted for 92% of all 1958-1977 production (Monsanto, 1980).
Polychlorinated biphenyls were versatile materials which found use in a variety of applications including plasticizers, printing inks, and heat exchange, dielectric, and hydraulic fluids. The dielectric properties, chemical stability, and noncombustibility of PCB fluids made them a particularly attractive alternative to flammable mineral oils for use in capacitors and indoor transformers. Concerns in the late-1960s regarding the environmental accumulation of highly chlorinated PCB mixtures resulted, in 1971, in a voluntary cessation of the manufacture of Aroclors 1232, 1248, 1260, 1262, and 1268; the introduction of Aroclor 1016; and to a restriction in PCB usage to totally enclosed systems. The Toxic Substances Control Act of 1976 made the manufacture, importation, sale, or use of PCBs illegal after 1978.
|
Louis Howard |
| 4/16/1990 |
Update or Other Action |
USEPA Memorandum Subject: Elmendorf AFB Deliverables and Operable Units (OU) from D. Johnson Environmental Scientist, AOO/A to George Hofer Chief Federal Facility Branch HW-074.
The following is a synopsis of two meetings that were held with staff members of ADEC and EPA. The first meeting was held on April 6, 1990 and the second was held on April 12, 1990. Attendees for the meetings from ADEC were Ron Klein, Max Schwenne, Colleen Burgh, Jennifer Roberts with Mary Siroki and Geoff Kany attending the first meeting.
The following reflects the input from ADEC regarding the document deliverables, determination of operable units, and schedules for inclusion to the Elmendorf AFB Interagency Agreement. This information was discussed with Bob Loiselle during your absence.
Document Deliverables: It was determined by mutual agreement that the same document deliverables now proposed for the Eielson IAG be incorporated into the Elmendorf IAG without change. ADEC agrees that for consistency and simplicity reasons the document deliverables for all Alaska IAG's remain the same.
Operable Units: Operable unit determination was based upon a hierarchy which was derived by either geographic or site characteristic similarities. The listed order was determined by severity of contamination (worst first) based upon common knowledge of the meeting participants.
Operable Unit #1 (Million Gallon Hill Area)-Sites SP-5/5A, OT-1, D-15, D-16, D-17, NS-2.
Operable Unit #2 (Air Force High Priority Sites-Sites S-5, D-4, D-10, FT-1
Operable Unit #3 (Landfills)-Sites D-5, D-6, D-7, D-8, D-9, D-11, D-12, D-13, NS-2
Operable Unit #4 (Hangar Floor Drains)-Sites IS-1, IS-2, IS-3, IS-4, IS-5, IS-6, IS-7, IS-8
Operable Unit #5 (Fuel Spill Sites)-Sites SP-1 thru SP-16, NS-3
Operable Unit #6 (UST/LUST Sites)-Approx. 35 known UST/LUST sites scattered around facility.
Operable Unit #7 (Misc. Sites)-Sites D-1, D-2, D-3, RD-1, S-l, S-3, S-4, S-6, S-7
Please note that of these operable units, the first three are probable definites for inclusion to the IAG. The last four have been included at this stage for discussion purposes and for understanding the perceived universe of sites at Elmendorf AFB.
Further refinement of this list and determination of schedules to be discussed on May 2, 1990 with ADEC. I will continue to discuss this subject with Bob as it develops, and would welcome any input you might have. |
Jennifer Roberts |
| 10/1/1991 |
Update or Other Action |
IRP Site Summary: Three sources were grouped into Operable Unit 3: SD52 (Cherry Hill Ditch fka NS-1), SD16 (Shop Waste Disposal Source fka D-17), and SS21 (PCB Transformer Storage fka S-6). These sources were grouped together on the basis of their proximity and relationship to Cherry Hill Ditch, for example, surface water runoff from SD16 drains into the ditch. SS21 is located north of Juniper Drive and east of Loop Road, at the site of Building 31-357, which was demolished. The location of Building 31-357 was determined through personnel interviews, records reviews, 1965 aerial photos, and as-built drawings (Black & Veatch, 1990, p. 4-173). Although the building was demolished, the concrete foundation and loading dock remained. SS21 was used as a storage area for PCB transformers during the 1970s. Large quantities of transformers were stored on the ground and leakage of PCBs and/or oils may have occurred.
|
Louis Howard |
| 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.
SS21 (formerly S-6) PCB Transformer Storage Area. Located north Juniper Drive and east of Loop Road, encompassing Bldg. 31-357. Old ITT site used to store PCB transformers in the 1970s. This site has low potential for environmental contamination, however a study shall determine the extent of contamination and the pathways affected to include soil sampling and analysis of the presence of PCBs.
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 |
| 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 and 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 |
| 5/7/1993 |
Update or Other Action |
In 1988, Black & Veatch (1990) placed a soil boring, collected soil samples at 15 feet and 20
feet below ground surface, and finished the boring as a monitoring well (IS7-01). A groundwater sample collected from IS7-01 was contaminated with chloroform at 0.32 ug/L and trichloroethene at 76 ug/l. The level of trichloroethene is above the drinking water maximum contaminant levels (MCLs). Total petroleum hydrocarbon (TPH) level was 2,000 ug/l. Fuels and solvents are the most likely sources of the contaminants detected. Because of the position of Monitoring Well IS7-01 relative to the dry well, sumps, and other potential sources, the contamination detected in the groundwater may not be representative of potential contamination from source SD30. Black & Veatch estimated that the direction of groundwater flow was to the south; the well may therefore be located upgradient of SD30 sources.
No Further Action document signed. As a result of the geophysical survey and soil sampling conducted at SD30, the recommended action for the outfall structure source areas investigated at SD30 is No Further Action (NFA). The primary criterion used to place sources into the NFA category as a result of the LFI at SD30 was whether the concentration of contaminants in any sample obtained during the LFI exceeded the risk-based criteria specified by the regulatory agencies. None of the soil samples collected during the LFI at SD30 contained analytes in excess of risk-based criteria. The criteria for NFA were met at each of the source sampling locations; therefore, NFA is justified for these locations.
Source of the groundwater contamination has been identified upgradient of SD30. This upgradient contamination near Source SD30 will be investigated during the OU3 remedial investigation.
The decision document was signed in May 7,1993 for SD30 by USAF Oscar V. Bryan Colonel Base Civil Engineer April 27, 1993 and EPA Marcia Combes and ADEC Jennifer Roberts on May 7, 1993.
However, groundwater is still contaminated and will be monitored while undergoing natural attenuation (at Operable Unit 3). |
Jennifer Roberts |
| 8/20/1993 |
Update or Other Action |
USAF Letter to EPA: Cherry Hill (SD52) Status. This letter, with your endorsement, is to serve as a record of decisions made regarding the status of Cherry Hill Ditch, SD52, during the site reconnaissance/project managers meeting on 20 May 1993.
It was agreed that the source area identifier, SD52, will be deleted from the program with the understanding that the historical impact to cherry hill ditch resulting from a solvent disposal trench, SD16, will continue to be investigated under Operable Unit (OU) 3; and, the impact to cherry hill ditch resulting from ongoing airfield operations will be addressed under the environmental compliance program.
3. The objective behind this revision is to provide clarity during the reporting and decision making phases of the Remedial Investigation and Feasibility Study being conducted on OU 3. |
Louis Howard |
| 8/30/1993 |
Meeting or Teleconference Held |
Unit 3 (OU 3) Management Plan to more adequately characterize contamination at possible source areas within the operable unit and to fill existing "data gaps" in the base-wide groundwater monitoring program. The changes summarized below were agreed upon by base personnel (Ms. Lisa Morris), AFCEE representatives, the United States Environmental Protection Agency (Ms. Marcia Combs), and the Alaska Department of Environmental Conservation (Ms. Jennifer Roberts and Mr. John Halverson).
The OU 3 Management Plan proposed that reflection seismic be used at OU 3 to determine the lateral and vertical extent of the Bootlegger Cove Clay Formation. In order to fully characterize the clay interval, reflection as well as refraction techniques were used at sites across the operable unit. Two existing groundwater monitoring wells were scheduled to be abandoned (W-11 and W-
12). Well W-ll was abandoned in July; however, Well W-12 could not be located and therefore was not abandoned.
The locations of hydropunch borings were modified so that groundwater could be investigate on an "operable unit-wide" basis rather than a "source area" basis. The locations of
groundwater monitoring wells were modified based on data acquired from the hydropunch investigation and to provide groundwater level information in areas of the base with limited
groundwater data.
The OU 3 Management Plan stated that 3 base supply wells would be sampled in June (02, 16, and 52). However, well 16 was inaccessible due to the presence of a pump housing and
was not sampled. The OU 3 Management Plan stated that four existing groundwater monitoring wells would be sampled during the first groundwater sampling event in June (W-10, W-13, BH-06, and IS8-01). Wells W-10 and W-13 could not be developed due to inadequate well construction and, therefore, were not sampled. These wells were subsequently abandoned in July.
Source Area SS21-Following the OU 3 Management Plan, screening for surface contamination by PCBs was performed using field test kits. The screening attempted to determine the lateral extent of PCB contamination in the surface soils. This screening information was used to determine the locations of soil borings and groundwater monitoring wells at the site.
|
Jennifer Roberts |
| 2/10/1994 |
Document, Report, or Work plan Review - other |
John Halverson sent comments to the USAF regarding OU3 Draft Final RI/FS report. Specifically, the text refers to asphalt capping as a remedial alternative for SS21. If capping is pursued, then it is not clear why removal of the concrete pad is necessary. Depending on the condition and grade of the existing concrete pad, it may be feasible to leave it in place until some future time if and when the site may be redeveloped. All alternatives describe treatment or removal of the top six inches of soil. It is not clear why only the top six inches of soil are proposed for remediation under these alternatives. Bioremediation is mentioned as an alternative under consideration and refers to it as an established technology for PCB cleanups.
ADEC is not familiar with PCB cleanups that have been accomplished through bioremediation. Reference to specific projects which have been successful should be included in the document. As noted in EPA's comments, bioremediation of PCBs is not considered well established. Capping is mentioned as a remedial alternative which will also use natural, physical, chemical, and biological processes which would be used to achieve the cleanup standard. PCBs are very persistent in most environmental settings. It would be more appropriate to state in the document: capping and institutional controls would be used to prevent completion of an exposure pathway and thus minimize risk to human health or ecological receptors. If in the future, the site is developed, appropriate health and safety issues and cleanup requirements would need to be properly addressed. Finally, the estimates on cost and the effectiveness/cost quotient may be overly optimistic given the uncertainties of bioremediating PCBs. There should be some type of uncertainty factor or analysis built into the evaluation process. |
John Halverson |
| 4/21/1994 |
Update or Other Action |
Sample Plan PCBs in sediment at Cherry Hill Ditch received. Record Keeping: Analysis required and all pertinent field records shall recorded on AF Form 2751s or 2752s and 2754s and maintained in Bioenvironmental Engineering 's IRP OU 3 file folder.
2. Equipment Decontamination:Equipment shall be decontaminated before and after each use as follows:
- Scrub equipment with a solution of potable water and Alconox.
- Rinse with potable water.
- Final rinse with distilled water.
- Air dry on clean surface
- Wrap with aluminum foil shiny side out for storage.
3. Equipment and Method: a. Four samples will be collected, three from Cherry Hill Ditch (CHD) and one from the storm sewer intercept manhole. No field screening will be-utilized. The excavated area in CHD will be approximately ten feet long by two feet wide by thirty inches deep.
b. Stainless steel push rods or spoons/scoops will be utilized to obtain samples from 0-3 inches down and deposited into a stainless steel bowl. Three composite samples will be taken
at cross sections across CHD, one at each end and the middle of the excavated area (see sketch, atch 1). The excavation will be approximately five feet length wise on each side of the "hot
sample location" and two feet wide and thirty inches in depth. The composite sediment from each cross-section shall be completely mixed and then deposited into the sample jar utilizing a
stainless steel spoon. There is enough equipment on hand to accomplish each sampling location without reusing/decontaminating equipment in the field.
c. One grab sample will be taken from the bottom of the intercept manhole basin of the road culvert and storm sewer( see sketch, atch f). A steel shovel will be used to initially collect the sediment at the bottom of the basin and then a small stainless steel spoon/scope will be used to transfer the sediment into the sample collection jar. Note; this intercept manhole always has water running through it.
4. Sample Storage, Transport and Labeling: Samples shall be stored in an ice cooler at 4 degrees Celsius. Protectie bubblewrap will be used to minimize the risk of breakage. Samples will be transported directly after sampling directly to Commercial Testing & Engineering Co., Anchorage, AK. Labels will be marked with the following information:
- Project name.
- Client
- Sample identification number.
- Sample type.
- Sampler's name or initials
- Date and time
5. Sample Analysis: Aroclor 1260, EPA 8080
6. No QA/QC analysis blanks will be performed and no chain of custody cards will be used.
7. Sampler: Keith J. Barnack, Environmental Engineer, Bioenvironmental Engineering Flight, Elmendorf AFB. |
John Halverson |
| 4/22/1994 |
Document, Report, or Work plan Review - other |
ADEC letter to USAF RE: Cherry Hill Ditch Storm Culvert Design; Final Design Submittal (100%) March 28, 1994. Most of the department's comments on the 90% design have been
adequately addressed, however, clarification of the following items is necessary:
Sediments a) The design calls for completion of the storm-drain by-pass prior to conducting work in the existing creek. If work in the creek can not be done under dry conditions (all water diverted to the storm-drain by-pass) silt fencing will be placed at downstream culvert. Any sediments that are collected will need to be characterized and disposed of properly, with department approval.
b) Sediments from the catch basin and upstream culvert will need to be removed characterized and disposed of properly, with department approval.
c) The department requests submittal of detailed plans for sampling in the area where elevated concentrations of PCBs have previously been detected. The submitted design states field screening and laboratory analyses will be conducted, but does not provide details. The additional plans should define who will conduct the sampling, how many samples will be collected from field screening, how many samples will be submitted to a laboratory for analysis (or at least a methodology for how this will be determined), and should include QA/QC details.
d) Plans for containing, characterizing and disposing of sediments removed during the project (items "a-c" above) need to be reviewed and approved by the department prior to conducting the work.
System Design- e) The department has reviewed the design and in accordance with 18 AAC 72, Waste Water Disposal Regulations, has no objection to the treatment and control system identified in the submittal provided the following requirements are met:
1) As-built drawings of the project be submitted to our Anchorage District Office, attention Keven Kleweno, within 90 days after the project's start-up date under the stamp of a Professional Engineer;
2) EAFB provide the level of maintenance specified by the design engineer; and,
3) If de-watering is necessary, EAFB meet the substantive requirements of any waste water discharge permit that would normally be required. This would entail insuring that any discharge does not cause a violation of the state water quality standards. |
John Halverson |
| 6/20/1994 |
Update or Other Action |
USAF sent a fax request for concurrence regarding SS21. Fax references Halverson's conversation with Lisa Morris, last week regarding the proposed construction of 6,000 square foot training facility for the Alaska National Guard (ANG) near SS21, with a paved parking lot encompassing nearly 70,000 square feet. Siting of the facility will be near Nutmeg and Elm streets (NOW called 12th Street and Gibson Avenue). AF requests concurrence on the revised location as to not impeded future cleanup efforts. ADEC concurred on 6/20/1994. |
John Halverson |
| 8/8/1994 |
Document, Report, or Work plan Review - other |
ADEC John Halverson sent USAF Larry Underbakke letter re: OU-3 Draft RI Report. The report does not contain a description of work that has been conducted at Cherry Hill Ditch. We understand that at the time the report was being prepared the culvert and ditch work had not been completed, therefore, it was not possible to include it in the draft.
However, the ditch has been rebuilt the potential for exposure to contaminated sediments or water in the ditch between Acacia Drive and Cherry Street has been eliminated (other than if someone excavates the site in the future). The final report should include a description of work that has been completed and analytical results from samples collected during the removal action. The risk assessment should also take the ditch work into account.
Several of the figures show contaminant concentrations in both micrograms and milligrams per kilogram of soil. Use of consistent units of measure in figures showing contaminant distribution
would simplify review of the data. The department concurs with EPA comments on the risk assessment.
Pg. E-2 - The summary states four base water supply wells were sampled. However, the remainder of the report indicates only three of the wells were sampled (base wells 2, 40, and 52).
Section 2.4.1 - The text in this section does not address heptachlor epoxide, which according to the appendix was present at concentrations which exceeded the MCL.
Section 3.2.2 - The section notes monitoring well W-10 could not be developed due to increasing silt accumulation in the well. It is not clear if W-10 was re-developed and sampled at a later time or if it was properly abandoned.
Section 4.2.3 - The second bullet states concentrations of organic constituents in groundwater at OU3 were compared to concentrations upgradient at OU4. While this is appropriate, compounds should not be eliminated from the COPC based solely on the fact that they are present upgradient in, or downgradient of, another contaminant source area.
Section 4 - Section three notes two surface water samples (SW-1 and SW-2) were collected from a drainage area, however the results are not described in section 4. Discussion of the results should be included.
Section 4.3.5 - The second paragraph states that the surface water sampling efforts at SD16 were related to compliance and the results were forwarded to the compliance staff. The section should provide more detail on the sample results and why they were not retained in the RI.
Section 4.3.5.2 - This section discusses surface water sampling and again refers to compliance issues. It states surface water sampling data will not be used in the risk assessment. As noted above, this needs to be further explained or justified.
Section 4.3.5.3 - Nitrate or nitrite concentrations appear to be elevated in several of the MWs, however, they are not listed as a COPC. It is unclear why they are not included.
Section 4.3.5.3 - The section on potential relationships between soil and groundwater contamination within the OU3 east area excludes soils at SD31. It is not clear why this information was excluded.
Table 6-3 - The table show compounds that were eliminated from the list of COPC due to the fact they did not exceed the risk based screening level. It is not clear whether cumulative risk from all the contaminants present in an area was taken into consideration prior to making this determination.
Table 7-1 - The table refers to the Alaska Cleanup Matrix for non-UST soils as a TBC, which is correct. However, some of the petroleum contamination near SD16 is noted as potentially coming from USTs. Please note, the soil cleanup matrix is included in Alaska's UST regulations (18 AAC 78.315) and thus the matrix is an ARAR with respect to contaminants from regulated USTs. |
John Halverson |
| 10/3/1994 |
Update or Other Action |
EPA sent comment letter to Air Force re: Clarification and Additional Information on the Administrative Record regarding the schedule for OU3 CERCLA activities at Elmendorf Air Force Base. According to the Federal Facilities Agreement (FFA) schedule for Elmendorf AFB, EPA received the draft Remedial Investigation and Baseline Risk Assessment (RI/RA) report for OU3, on July 11, 1994. That document is a secondary document as defined in the FFA. EPA provided review comments on the draft RI/RA to the Air Force on August 5, 1994. On August 4, 1994, a Feasibility Study scoping meeting was held with Air Force, Radian Corporation, Alaska Department of Environmental Conservation (ADEC), and EPA present. Finally, EPA received Air Force's response to the OU3 RI/RA comments on September 28, 1994.
At the August 4, 1994 Feasibility Study scoping meeting it was decided by all parties that a feasibility study was not required at Operable Unit 3. OU3 RI results provided the basis for this decision, which indicated that cumulative risks for all media, under the future residential (RME) scenario at each of the source areas, did not exceed a 10 - 5 carcinogenic risk level or a hazard index (HI) of 1 for non-carcinogenic risks.
At the meeting, it was agreed that the next revision of the OU3 RI report would include additional information on remedial field work completed at Cherry Hill Ditch, as well as the rationale for why a feasibility study would not be performed at OU3. Schedules were discussed generically, and it was decided that the response to comments would be provided according to schedule, but the final RI report would be completed according to the Feasibility Study schedule. Acceleration of the overall schedule, and particularly the proposed plan, was also discussed.
The cover letter to the Response to Comments that EPA received September 28, 1994 stated that at the meeting, it was agreed that the response to comments would be acceptable "in lieu of a Final RI". For purposes of clarification, the Response to Comments are not acceptable in lieu of the final RI. A final RI report including additional information discussed above is scheduled to be submitted to EPA and ADEC for review on November 11, 1994.
EPA contacted Larry Underbakke at Elmendorf AFB on September 29, 1994 to clarify the schedules and to confirm that a Final RI will be completed according to the FFA schedule for the Feasibility Study. It is anticipated that a draft final will not be necessary and that the schedules will be expedited accordingly. |
John Halverson |
| 12/9/1994 |
Document, Report, or Work plan Review - other |
EPA Comments on draft RI/FS report. The title of the document indicates that a Feasibility Study was performed, and the text of Chapter 7 repeatedly concludes that specific media will not be further evaluated for remedial action in the feasibility study. The
references to a feasibility study are misleading. At the project managers meeting on August-4, 1994, the issue of whether or not a feasibility study was warranted for OU3 was discussed. Information available at that time indicated that cumulative risks under the most conservative residential scenario for all source areas evaluated did not exceed a 10-5 carcinogenic level nor a hazard index of 1 for noncarcinogenic risks. At SS21, information presented indicated that a military construction project was probable at that site, involving construction of a building.
section 7.4.3, page 7-18: This section is supposed to summarize human health and ecological risks for SS21 soils. The text is poorly written and lacks sufficient detail to support any decisions. Statements are not qualified with supporting rationale; the text incorrectly references section 7.6.4 for discussions on groundwater and cumulative risks at SS21 (section 7.6.3 contains a limited discussion); and it remains unclear if PCBs contribute to groundwater risks at SS21.
Section 7.4.4, page 7-18: Significant PCB contamination in the soils at SS21 exists, warranting action. The text in this section only states that alternatives for SS21 soils contamination are being
evaluated and that an action will be performed. It is not
acceptable to provide a description of the response action
selected in the Proposed Plan. At a minimum, an action
memorandum should be prepared which describes the
alternatives considered, evaluation criteria, and the preferred alternative. The preferred alternative must be agreed to by all parties to the FFA, prior to acceptance of the final RI. The action memorandum should also include an execution plan to identify the applicable program, projected cost, available funding, and the schedule of the planned action.
Section 7.11 page 7-49: This section presents recommendations for soil and groundwater at OU3. This section does not accurately provide the basis and supporting rationale for decisions made for OU3. Statements are made that are not qualified (i.e. natural attenuation claims, and that human health will be protected); remedial action planned for SS21 has not been presented; and based on new information presented for SS21, EPA is not in agreement that a feasibility study will not be performed at this time.
It is unclear what is intended by the statement "Natural attenuation should be allowed to occur" for groundwater. Final action should be based on risk managment decisions and the basis of those decisions should be clearly and concisely provided as justification for the recommendations for soil and groundwater within OU3.
Additionally, an institutional control plan and groundwater monitoring program should be presented or outlined and included in this document or presented separately prior to the proposed plan. This plan should specify the porposed groundwater monitoring locations, sampling frequency, analytical program and reporting mechanism. A contingency plan should also be presented to guide future actions if the volatile organic compounds in groundwater increase in concentration due to upgradient sources identified on page 7-44. |
John Halverson |
| 2/10/1995 |
Document, Report, or Work plan Review - other |
ADEC letter to USAF RE: Operable Unit 3, Draft Final Remedial Investigation/Feasibility Study Report; January 1995. Section 8.2.2 describes asphalt capping as a remedial alternative for SS21. If capping is pursued, it is not clear that removal of the concrete pad is necessary. Removal and disposal of the concrete pad raises other issues such as PCBs in, or adhering to, the concrete and any land disposal laws or regulations that may apply. Depending on the condition and grade of the existing concrete pad, it may be feasible to leave it in place until some future time if and when
the site may be developed.
Sections 8.2.3, 8.2.4 and 8.2.5 all describe treatment or removal of the top six (6) inches of soil. It is not clear why only the top six inches of soil are proposed for remediation under these alternatives. Alternative five (5), which is excavation and treatment, calls for excavating and treating soil containing more than 1 mg/kg PCB.
Section 8.2.4 describes bioremediation as an alternative under consideration and refers to it as an established technology for PCB cleanups. We are not familiar with PCB cleanups that have been accomplished through bioremediation. Reference to specific projects which have been successful should be included. As noted in EPA comments, bioremediation of PCBs is not
considered well established.
Section 9.2.2 provides an analysis of capping as a remedial alternative. It states natural physical, chemical, and biological processes would be used to achieve the cleanup standard.
PCBs are very persistent in most environmental settings. It would be more appropriate to state capping and institutional controls would be used to prevent completion of an exposure pathway
and thus minimize risk to human health or ecological receptors. If in the future the site is developed appropriate health and safety issues and cleanup requirements would need to be properly addressed.
Page 9-12 describes in-situ bioremediation. The estimates on cost and the effectiveness/cost quotient may be overly optimistic given the uncertainties of bioremediating PCBs. There should be some type of uncertainty factor or analysis built into the evaluation process. |
John Halverson |
| 3/8/1995 |
CERCLA RI Report Approved |
The results of the remedial investigation at source SS21 verified that the bulk of the soil contamination is associated with PCB-1260. Aroclor 1016 was detected at 3.5 mg/kg SS-10 (E321-SS-03 0-0.5' bgs). The most likely sources for this contamination, which is most pronounced in the vicinity of the former transformer storage pad, are leaks of PCB oil from electrical transformers.
The VOC and SVOC contamination observed frequently in association with PCB contamination may also be related to transformer oils. Pesticides appear to be widespread throughout the site and throughout much of OU3. Based on the results of this investigation, it is not believed that a site specific source for this pesticide contamination is present at SS21. No obvious potenital sources could be identified for the isolated elevations of lead and arsenic observed on site.
Table 4-17 Groundwater screening results indicated that SS21 had chlorinated solvents in SB-02 at 5.5 for TCE. The TCE levels observed in groundwater from wells at source S821 (MW5 and MW6) are likely associated with downgradient migration of groundwater contamination from source SD16, with the possible contribution of additional low levels of TeE from the soil at source SS21.
The levels of VOCs (primarily TeE and benzene) detected in groundwater samples from wells installed at source SD16 suggest that there is a potential source or sources of contamination at source SD16, primarily in the eastern half of the area. These sources could potentially include the former waste disposal trenches, vehicle maintenance activities and the underground storage tanks located in the northeast corner of SD16 (approximately upgraciient from well MW13).
Further contributions to contamination could come from source SS21, located downradient from source SD16. However, based on the available information regarding groundwater flow direction and the lateral extent of source SD 16, it is not possible to conclude that VOC concentrations found in samples from east intersource area wells (mainly MW25, MW15, MW1, IS8) are related to a source of contamination at SD16. The contamination found in these wells may be associated with pulses of contamination migrating downgradient from OU 4, or with other yet unknown sources of contamination within the OU 3 east groundwater area. |
John Halverson |
| 3/8/1995 |
Risk Assessment Report Approved |
RI/FS with risk assessment final version received and approved.
Since all of the soil areas of interest are encompassed within either one or two groundwater areas of interest at OU3, the discussion of analytical results, nature and extent of contamination, and potential sources of contamination is divided into two areas:
OU3 East: including soils areas of interest SD16, SS21, east intersource area (including SD31), and the east groundwater area; and
OU3 West: including soils areas of interest SD52 and west intersource area and the west groundwater area.
The carcinogenic evaluation for the worst-case scenario (residential-RME) showed a total risk of 1.3 x 10-4 for source SS21. No other exposure scenarios were associated with a risk in excess of 1.0 x 10-4. The evaluation of the potential for noncarcinogenic effects produced a hazard index of 1.3 at SS21 under the residential RME scenario only. All other scenarios have hazard indices of less than 1.0. Site remediation goals for Superfund sites have generally been in the range of 10-4 to 10-6 risk for carcinogens. However, Table 4-17 Summary of GW Screening Results from OU3 East GW area soil borings for SS21 TCE sample results exceeding the 5 ug/L cleanup level for the following: SB-02 5.5 ug/L and SB-10 10 ug/L.
Ecological Assessment: Ecological Quotient (EQ) less than 1.0 indicates that the adverse effect being evaluated is unlikely to occur. EQ greater than 1.0 indicates that an adverse effect is possible. Caveat: due to the health conservative methodology used in the assessment, an EQ of greater than 1.0 DOES NOT indicate an adverse effect WILL occur. No EQs for moose, merlin, or peregrine falcon exceeded 1.0. Meadow vole EQs for several inorganics exceeded 1.0 at one or more source areas. However, the upper threshold limit of the background concentrations for the contaminants also cause the EQ to exceed 1.0.
Therefore, the EQs are probably overestimating the impacts to meadow voles. Exposures for black-capped chickadees, masked shrews and meadow voles feeding in the vicinity of Cherry Hill Ditch may be significant. However, due to the small areal extent of contamination, significant populations of these indicator species or other animals most likely are not threatened by the contaminants. |
John Halverson |
| 4/17/1995 |
Update or Other Action |
USAF sent action memorandum regarding State Concern about source of contamination at or near SS57 and SS62. One of John Halverson's comments, dated 28 February 1995, on the draft SERA Phase I corrective action plan was the possible lack of continuity between the CAP and the RI/FS for OU3. The comment questioned where the source was on a trichloroethylene (TCE) hit in the groundwater at or near SS57 and SS62. During a meeting with the meeting on April 5, 1995 with Mr. Halverson, Mayer, and Underbakke, they agreed that the monitoring wells up gradient and down gradient of SS62 would be placed into our long-term monitoring program. These wells will be monitored to establish a trend in the TCE concentrations. Data from the monitoring wells will be gathered for a minimum of four rounds of biannual sampling (two years). At the end of this sampling period, the four sample rounds will be used to establish a trend and a decision made if the source still exists. The wells that will be included in these rounds of sampling will be up gradient: OU3MW11, 49MW02, at site: 48WL01 and 48WL03; and down gradient: OU5MW-01, SP1-02 and OU5MW-02. Sampling of wells 49WL02 and 48WL01 is pending funding. |
John Halverson |
| 5/3/1995 |
Document, Report, or Work plan Review - other |
Review comments for SERA Phase I Corrective Action Plan April 19995 from John Halverson to 3 SUG/CEVR Elmendorf. Based on information that has been provided to date, closure of the following sites with regard to soil contamination is warranted. If in the future contaminated soil or groundwater are generated at the sites it will need to be handled in accordance with the applicable laws and regulations. Separate closure letters should be prepared for the sites in order to document them for the record.
SS57 - Oil Stained Soil (comer of Third Street and Maple Street)
The department does not object to a no further action decision for SS57 under SERA since
no elevated concentrations of contaminants were identified in the soil and groundwater
contamination below the site was evaluated in the OU3 risk assessment. Base-wide groundwater monitoring is being conducted under the CERCLA program and should identify any future groundwater issues that need to be addressed. |
John Halverson |
| 5/12/1995 |
Document, Report, or Work plan Review - other |
ADEC J. Halverson letter to J. Williamson/L. Underbakke USAF re: Draft Proposed Plan for OU3. The department has reviewed the draft proposed plan for OU3, which we received on April
15,1995. We have also reviewed and concur with EPA's comments. Additional comments are provided below.
1) The first bullet under the purposes of the proposed plan identifies contaminants found within OU3. If contaminant types are to be listed, then PCBs should be included.
2) The third paragraph under site background states, "The study areas which were not associated with any of the sources, are called the East Intersource Area and the West Intersource Area." It is somewhat misleading or confusing to state the intersource areas are not associated with the source areas. If they are not
associated, why were they studied. It would be better to state the Intersource areas include land surrounding and downgradient of the source areas.
3) The fourth paragraph under the site background states, "Releases of these solvents and fuels occurred from...". PCBs are not a solvent or a fuel. It may be better to state, "Releases of these contaminants..." or "... wastes...".
4) The paragraph noted under comment #3 also states the intersource areas consist of eight (8) and three (3) wells. It should state work within the intersource areas included installing and sampling a specific number of monitoring wells.
5) The first paragraph under Summary of Site Contamination and Risks states, "Then, a human health risk assessment was performed to see if there were any potential health effects in OU3." It should state the risk assessment was done to estimate the
amount of any potential risk to human health posed by contaminants within OU3.
6) The second paragraph under Groundwater, on page 4, states that none of the sites in OU3 appear to be current sources of the solvents and fuel found in the groundwater. The sites are sources of the groundwater contamination. It may be appropriate to state soil above the watertable was not found to have high contaminant concentrations, thus future leaching to the groundwater does not appear to be a concern. However, contaminant in the smear zone and groundwater impacts are still present at the source areas. The source areas are at least a part of the source for the current groundwater impacts.
7) The second to last sentence in the first paragraph under Sites Requiring Cleanup states, "The risk scenario is that the site is for a hypothetical resident, but the site is not residential." This wording should be clarified.
8) On page 10 under State Acceptance, it states, "The State accepts the preferred alternative identified in the Proposed Plan with the contingency to excavate and treat the soil." I am not aware of an agreed upon contingency if the treatability study shows bioremediation is not feasible. Excavation and either treatment or disposal may be acceptable, but I do not recall this addressed in any detail or one method being selected over the other.
9) Under the glossary on page 12, the definition for the Alaska Cleanup Matrix should read, "An Alaska regulation outlining cleanup levels for soil contaminated by petroleum releases from underground storage tanks (USTs). An identical matrix table contains guidance for soil cleanup levels at non-UST sites."
10) The glossary contains, "Alaska Department of Environmental Control". It should be "Conservation" rather than "Control". |
John Halverson |
| 6/8/1995 |
Document, Report, or Work plan Review - other |
John Halverson (ADEC) sent a letter to USAF RE: Draft Final Proposed Plan for OU3. The department has reviewed the Draft Final Proposed Plan for OU3, which we received on June 1, 1995. Comments on the plan are provided below.
1) Table #1 - It would help to cite, in or beneath the table, the source of the standards that are listed in the table.
2) Table #1 - It is not clear why 10 ppm is listed as the standard for PCB in soil. It is my understanding we are using the Guidance for Remedial Action at Superfund Sites with PCB Contamination (EPA, August 1990), rather the TSCA, as the standard. The preferred remedial alternative for soil at SS21 is use bioremediation to achieve 1 ppm or less PCB. Therefore, the standard in the table should be 1 ppm. It also is not clear that 10 ppm PCB is the appropriate standard for PCB in sediments in Cherry Hill Ditch.
3) Table #2 - It is confusing to have surface water and sediment standards grouped together in one table. Additionally, the basis of the sediment standards listed in the table is not clear.
4) Sites Requiring Cleanup - It would be easier to read and decipher this information if it were broken out into two paragraphs or possibly a bullet format. Also, the reference to Figure 3 should be replace with Figure 2.
5) Summary of Cleanup Alternatives - In the description of capping the word "will" should be replaced with "would".
6) Alternative 3 - The section states disposal of excavated soil would need to occur at a TSCA permitted hazardous waste disposal facility in the lower 48. It is my understanding soil with less than 1 ppm PCB could be disposed of in the Anchorage Regional Landfill. This may be a more cost effective disposal option.
7) State Acceptance - Since I am not convinced that on-site treatment is preferable to offsite disposal if the proposed bioremediation does not work, I recommend rewording the
paragraph to state, "... with the contingency to excavate and treat or dispose of the soil." Ideally we would provide more specific details on exactly what the contingency is, however, I do not think we have consensus on a detailed alternative at this point in time.
8) Rationale for Selecting the Preferred Alternative - I recommend including Alternative 3 as an option rather than limiting the contingency to Alternative 5. |
John Halverson |
| 6/8/1995 |
Document, Report, or Work plan Review - other |
Marcia Combes USEPA sent comment letter to Air Force RE: OU3 Proposed Plan Draft Final Comments. Surface Water and Sediments, page 3. The presence of surface water and sediments should be clarified to indicate the relative scale that is involved. That is, the fact that the surface water expression is seasonal-and covers a very small area as a result of snow melt and surface drainage during periods of high runoff.
Figures 2 and 3. The boundaries for OU3 are inconsistently indicated on these two figures. The text on page 4 discusses the movement of contaminants and states that by the time the compounds reach the southern boundaries of OU3, the concentrations will be below 1 part per billion and will not increase above concentrations seen today. According to Figure 3, the plumes have already reached and gone beyond the OU3 southern boundary. These discrepancies should be corrected.
Page 8. The proposed plan is unclear regarding the preferred alternative for cleanup of groundwater. In all previous discussions it was agreed that based on the groundwater contamination present within the intersource areas (TCE, BEHP, and lead), institutional controls with long-term monitoring would be proposed for groundwater in OU3. This discussion needs to be emphasized and clarified.
It is suggested that a separate paragraph be added under the section entitled "Sites Requiring Cleanup". A general discussion should be included that indicates that we've identified and controlled known sources of contamination, that contamination is sporadic and not widespread, the contamination does not appear to be moving, modeling estimates fate and transport of contaminants and further predicts plume concentrations and corresponding timeframes (i.e., cleanup) and that at this time, long term monitoring with institutional controls is an appropriate action to take. |
John Halverson |
| 6/20/1995 |
CERCLA Proposed Plan |
The Proposed Plan approved. OU 3 includes base housing, maintenance, and operation
facilities. OU 3 is located on relatively flat terrain at an approximate elevation of 150 feet above sea level. OU 3 consists of three source areas and two study areas. (See Figure 2.) The source areas include: a shop waste disposal site (SD16), the former polychlorinated biphenyls
(PCB) transformer storage area (SS21), Cherry Hill Ditch (SD52), and a dry well at an aircraft maintenance hangar (SD3 1). Site SD52 is not considered a source of contamination but did receive contaminants from SD 16.
The following is a summary of the risks and the actions already taken at each of the OU 3
sites:
. Site SD3 1 : The contamination at SD3 1 was removed.
The action is considered to be protective of human health and the environment and no further action is necessary at SD31.
Site SD52: The work performed at SD52 removed the most contaminated soil. The current risk at SD52 is within established guidelines. No further action is planned for this site.
Site SD16: No action is planned at SD 16 because the risk at SD16 is within established health guidelines. Therefore, no further action is planned at this site.
Site SS21: The contamination present at the surface at SS21 will require further action.
Based on the risks and the cleanup actions taken at OU 3, only the soil at site SS21 requires further cleanup action.
Institutional controls will also be established at OU 3. No drinking water wells will be allowed in OU 3. The quality of the groundwater will also be monitored to track the
movement and reduction in contamination happening over time.
The Proposed Plan lists PCBs and arsenic in the soils at SS21 and chlorinated solvents, benzene, cadmium and lead in the GW. Modeling of contaminant movement in GW from OU3 shows that the contaminants will not affect people, plants, animals or surface water in OU5 located to the south.
To confirm natural attenuation of the contaminants of concern (COCs) in the groundwater (GW), the GW will be routinely monitored to make sure no contaminants are moving from these sites. Selected remedy for SS21 will be in-situ treatment of the PCB contaminated soils using biological processes (1996 treatability study efforts during testing showed this to be unsuccessful and removal with disposal off site was implemented). |
John Halverson |
| 9/14/1995 |
Document, Report, or Work plan Review - other |
EPA letter to Air Force RE: OU3 Draft ROD comments. The ROD, in general, is unclear about the implementation of institutional controls for groundwater and the identification of groundwater monitoring. Specifically, it is mentioned in the text a number of times, but it is not apparent if the [groundwater] monitoring applies to SS21 only or to other source areas. Other source areas within OU3 do have exceedences above MCLs (i.e. OU3 East, MW-11, MW-12, for TCE), and those areas should be included in a long-term [groundwater] monitoring plan.
Page 2, Declaration, first paragraph, last sentence. The language "if the land or groundwater use were changed" should be deleted. The PCBs present in the surface soil at SS21 currently pose a threat to children that frequent that area.
The Assessment of the Site section should include information on the other source areas (including soils and groundwater) within OU3, not just SS21.
Page 2, Declaration, third paragraph. This paragraph contains discussions regarding semi-annual groundwater monitoring, to evaluate contaminant migration and reduction of contaminant concentrations [in groundwater] by intrinsic remediation. It is unclear whether this applies to SS21 only or other source areas within OU3. Intrinsic remediation has never been considered a remedial option for PCBs in groundwater. There are other source areas that should be monitored due to MCL exceedences, and intrinsic remediation could be considered an appropriate remedy in this case. The text should be clarified accordingly.
Section 3.1, page 3-4. The last paragraph of this section does not provide adequate information regarding the establishment of COPCs and the process that was followed. Please refer to language on the OU4 ROD, page 3-3,4. The references to "potential regulatory levels" throughout
section 3.1.1, should be removed--they are vague and unclear. Use of the terminology "risk based screening levels" with the sources of the screening levels (i.e., residential exposure assumptions, standard EPA default exposure assumptions, 10-6 risk levels, etc.) is more
appropriate.
Tables 3-4,5, pages 3-11,12. The Proposed Action Level of 10 ppm (assumed to be a screening level) should be replaced with 1 ppm, as a more appropriate screening level. Again, the RCRA Proposed Subpart S numbers do not apply here. EPA Region 10 risk-based screening levels should be used.
Section 3.3, page 3-32,33. The risk assessment discussions should include more information regarding the approach and calculation of groundwater risk. For example, what groundwater concentrations were used to calculate risk--was it point by point, averaged over an entire area, based on [groundwater] modeling results over 30 years? The approach should be briefly described and justified. The text does not include any discussions on risk in groundwater as a result of high lead levels at W13 (0.42 mg/L, Table 3-10, page 3-25). This issue should be addressed in the ROD.
Section 5.0, page 5-1, third paragraph. This paragraph states that groundwater will be monitored. Additional detail should be provided on areas that will be monitored, what contaminants [in groundwater] will be monitored for and for how long. The text states that further response actions will be considered if [groundwater] "monitoring" shows an increase in concentrations. More specific information should be provided on what monitoring this is referring to (i.e., soil, groundwater, where-- OU3, MW11, SS21?). What about [groundwater] monitoring for all the other sites, again this issue should be clarified. |
John Halverson |
| 9/20/1995 |
Document, Report, or Work plan Review - other |
John Halverson commented on the Draft ROD for OU3 in a letter to the USAF. The ROD focuses on PCBs in the soil and does not adequately address other source areas and contaminants of concern. For example: Statement and Purpose only refers to PCBs at SS21. The document must be modified to more clearly describe contaminants found in other areas and how they will be addressed until ARARs are satisfactorily met.
Groundwater monitoring and institutional controls are referenced in various sections of the ROD, but are not detailed. As currently written, the ROD does not adequately bring most of the source areas to closure or remediation. The Assessment of Site section only refers to PCBs at SS21, other source areas and contaminants [in soil and groundwater] need to be addressed.
Section 2.1 states the contaminant transport section states that before releases could be detected or remediated, constituents migrated... to the shallow water table. Since contaminants were intentionally disposed of in trenches at SD16 and the septic system at SD31, the previous statement is somewhat misleading and should be reworded to simply state that some of the soil contaminants have leached to the water table.
Tables 3-1 and 3-7 list proposed action levels for various contaminants in sediments. Alaska's soil cleanup matrix, specifically was developed to help prevent vadose zone contamination from leaching to groundwater. The matrix cleanup levels are not applicable to sediments in contact with surface water. Thus, the reference to the soil cleanup matrix should be deleted from the tables listing action levels for sediments.
Contaminants of concern identified in section 3.4 do not include groundwater contaminants. Groundwater contamination above ARARs is present beneath OU3. Longer groundwater monitoring will be implemented to determine contaminant concentration trends [in groundwater] and verify future compliance with ARARs.
Institutional controls are to be placed on the use of the groundwater from the shallow aquifer beneath the site to limit the potential for future human exposure to the contaminants. These issues need to be detailed in the ROD. The remedial action objectives, alternatives, comparative analysis section refers to only SS21. It should also address the other source areas and describe proposed [groundwater] monitoring and institutional controls.
Since groundwater contamination was identified beneath OU3 at concentrations exceeding State and Federal drinking water standards, the chemical specific ARARs section should include the drinking water standards.
The proposed remedial action is based on risks from PCBs in soil more than the potential for PCBs to migrate to the groundwater. In addition, there are other areas where fuel or solvent contamination, rather than PCBs, may act as continuing source for some additional groundwater impacts. These issues should be clarified. |
John Halverson |
| 10/12/1995 |
Update or Other Action |
OU3 Concrete Pad PCB Results: Concrete Pad A highest detections- 852 mg/kg Aroclor 1248 and 561 mg/kg Aroclor 1260 from 0 to 1" (SS-21A-CC-3) and 3.5 to 6" 8.5 mg/kg Aroclor 1248 and 20.3 mg/kg Aroclor 1260. Next highest SS-21A-CC-4: Aroclor 1260 18.2 mg/kg. |
John Halverson |
| 12/8/1995 |
Document, Report, or Work plan Review - other |
EPA provided comments on the OU 3 draft ROD dated October 1995. The following comments apply to the October draft final, which will under further changes and review based on the results of the treatability study at SS21.
Part I. Declaration, Assessment of the site, first paragraph (redline/strikeout version): The last sentence should be replaced with the following: "Groundwater risks at OU3 are within EPA's acceptable risk range (less than 10-4) under a future residential use scenario, which is considered conservative. On that basis, it was determined that further remedial action for groundwater is not required. Groundwater at OU3 will continue to be monitored under the Base's Comprehensive Groundwater Monitoring Program until cleanup levels are achieved and institutional controls will restrict access to the groundwater throughout OU3."
Part I. Declaration, Description of the Selected Remedy, first paragraph. The last bullet states that groundwater beneath OU3 will be monitored, and that the details are elsewhere in the ROD. The details of the groundwater monitoring, including institutional controls, should be highlighted in this section of the ROD. Specifics should include how many wells will be monitored for what contaminants, at what frequency and for how long.
Section 3.2 Page 3-22 first sentence: The text states that: "OU3 will not cause an impact to sensitive receptors". The discussion involves modeling of basewide groundwater contamination over the next 30 years, and corresponding predictions. The text should reflect the uncertainty associated with any [groundwater] modeling effort; contamination from OU3 is NOT EXPECTED to have an impact on sensitive receptors. The purpose of long-term [groundwater] monitoring is to ensure that [groundwater] modeling predictions are generally correct, or to indicate otherwise.
Section 4.1 Page 4-2 first paragraph: The second sentence states that groundwater will be sampled from wells within OU3 on a semi-annual basis. The text should mention that wells upgradient and downgradient of OU3 will also be monitored under the Base's Comprehensive Groundwater Monitoring Program. The last sentence states that [groundwater] monitoring will continue until contaminant levels are below MCLs. The text should specifically indicate which contaminants will be monitored until MCLs are met--will it ball of the COCs in Table 3-3 or TCE and BEHP, the major contributors to risk? The MCLs for the corresponding contaminants should also be included.
Section 4.2 page 4-2: An RAO should be established for the groundwater monitoring mentioned in the paragraph preceding this section.
Section 5.0 page 5-3: The third bullet states that groundwater beneath OU3 will be monitored, and that the details are elsewhere in the ROD. The details of the groundwater monitoring should be restated in this section of the ROD, and some critical elements have still not been included in this ROD. Specifics should include how many wells will be monitored for what contaminants, at what frequency and for how long.
Section 5.1.2 page 5-4: Chemical-specific ARARs for constituents that will be monitored in groundwater should be indicated and included in the text.
Section 5.2.5 page 5-7: Institutional controls for groundwater have been surprisingly deleted from the text. Based on the risks remaining in the groundwater, institutional controls, as well as monitoring, are appropriate and should be included as components of the selected remedy throughout the OU3 ROD. This change was not in the redline/strikeout format. |
John Halverson |
| 12/11/1995 |
Document, Report, or Work plan Review - other |
John Halverson provided comments on the Draft Final Record of Decision for OU3 to USAF Joe Williamson and Larry Underbakke. ADEC concurs with EPA's comments with additional comments of its own. It is ADEC's understanding that the treatability study will be completed before finalizing the ROD and that if bioremediation turns out to not be a feasible remedial alternative, the ROD will be revised and anther draft final will be submitted. Text states a review will be conducted five years after completion of the remedial action. A five year review is required if waste is left in place.
It is not clear if the review is proposed based on the PCBs at SS21, contaminants at other source areas, or both. Alternative 5 is to excavate the soil and treat it on site. Another alternative is to excavate and dispose of at another location on Base if the disposal area is already covered by institutional controls limiting future land use. Also if exposure to and migration of contaminants (PCBs) is limited by the site conditions. If the bioremediation treatability results are negative this may be an acceptable alternative that is not currently included in the ROD. If implementation of the remedial action results in the agreed upon cleanup level for PCBs (5 mg/kg) being met, then a five year review may not be necessary for soil action at SS21. The ROD does not include any reference to PCB impacts to and disposal of the concrete pads at the site.
The ROD refers to institutional controls (ICs) to limit use of groundwater from the shallow aquifer. It does not include any reference to ICs on management of soil that may be excavated from OU3 source areas during future construction projects. Ultimately, no further action decisions will be approved for each source area based on calculated risks in current and estimated future exposure scenarios. However, these decisions do not address identification, characterization, and management of the soil that may be excavated during future development. Real estate records or other appropriate land records should include documentation on where contaminated soil has been identified and remains in the ground. This would help land planners identify potential contaminated areas when proposing development on Base and may help in avoiding future compliance problems or contractor down time. |
John Halverson |
| 1/23/1996 |
Document, Report, or Work plan Review - other |
ADEC comment letter on Draft Work plan, OU3 SS21 Biotreatability Testing of PCB Contaminated Materials Stage 1 Bench Scale Test December 1995. Successful demonstration of the technology as it may apply to other sites is not limited to reducing 30 mg/kg to 5 mg/kg PCB. It is possible the process may be more effective with higher initial concentrations than with low initial concentrations. Controls with higher PCB concentrations for spiked samples would be better to evaluate the technology Request test be run at lower temperatures as would be found in field conditions than at higher room temperature and extrapolating what may happen at lower temperatures. Based on the schedule in the document, it appears that the ROD for OU3 could not be finalized by August at the earliest. The schedule for the project and finalizing the ROD needs to be clear and agreed upon by all agencies. |
John Halverson |
| 3/7/1996 |
Meeting or Teleconference Held |
Minutes from 7 March 1996 Conference Call. OU3 The project schedule will be completed today and distributed to the agencies Monday, March 11. Steve will be working to coordinate the delivery of the schedule to Tim Brincefield at EPA in Seattle.
Included in the cover letter will be a paragraph stating that we will be collecting additional soil at SS21 which will used by an AFCEE contractor to perform additional biotreatability studies. A spreadsheet was generated summarizing the health risk assessment work for SS19. Kim stated the spreadsheet did cover the additional information that AFCEE had requested.
The soil samples should be collected at SS21 early next week. We will need to shovel more snow and use the auger in order to collect the samples. We have enough soil in Austin to give to AFCEE; however, when we did the analysis on the "hotspot" it had less than one part per million PCBs. Larry noted that the National Guard was at that site last year, their soil was stockpiled at the "hotspot" and could have possibly disturbed the soil.
Steve commented he would like to have Kim and Larry review the final treatability work plan one last time. Per the EPA's request, we added some QA/QC and Health & Safety information, and also took
out the 1,000 parts per million test. Steve noted since there were substantial changes made to the plan, he would feel more comfortable sitting down to review the document with Kim and Larry next week. |
Ray Burger |
| 7/11/1996 |
Update or Other Action |
(Old R:Base Action Code = RI - Remedial Investigation). RI action added on 02/11/1997. Air Force Relative Risk Evaluation Worksheet dated 8/4/95 indicated RI is the current phase. Final sampling dune during summer 1996 to define area of PCB contamination and aid in selection of a feasible remedy from the alternatives identified in the Propose Plan (PP). |
John Halverson |
| 7/15/1996 |
Update or Other Action |
AF letter re: Extension for Record of Decision for Operable Unit 3. Request for an extension to 30 August 1996 for the draft final ROD for OU3. Current deadline is 8 July 1996. Requested extension is for 54 days. At the 25 October 1995 Project Managers meeting for OU3 a treatability study was agreed upon by the EPA, ADEC and AF project managers to avoid a contingency ROD. The original ROD had bioremediation as the preferred alternative and thermal remediation as the contingency alternative. The treatabilty study was completed approximately on 17 June 1996, but unfortunately the bioremediation test was unsuccessful.
EPA, AF, ADEC Project Managers met on 12 June 1996 to discuss alternatives. Good cause exists for this extension because of the time required to conduct the treatability study, choose another alternative and rewrite the ROD. The extension will affect the schedule for the Remedial Design. The new date for the OU3 Remedial Design will be 30 January 1997. |
John Halverson |
| 9/2/1996 |
Update or Other Action |
Operable Unit 3, SS21 Biotreatability Testing of PCB-Contaminated Materials Final Report. Elmendorf Air Force Base (AFB) sponsored a treatability study designed to assist the AFB in evaluating bioremediation as a possible approach for degrading polychlorinated biphenyls (PCBs) at Source Area SS21, Operable Unit (OU) 3. SS21 was selected because it has soil and concrete contaminated with PCBs. This treatability study evaluated a bioaugmentation technology which was identified as the most appropriate remedy in the Proposed Plan for OU3.
The primary objective of the treatability study was to determine whether a bioremediation technology would be effective for reducing the total PCB concentrations in the soils and concrete to less than 5 mg/kg. This is a RISK-BASED LEVEL which was agreed upon in meetings with the Base, the U.S. Environmental Protection Agency (USEPA), and the Alaska Department of Environmental Conservation (ADEC). The purpose of treating the concrete and soil at SS21 is to remove or degrade the PCB contamination so that the site will not be encumbered by future land use restrictions.
For the bench-scale tests, soil pans and concrete specimens were used to simulate the biotreatment process. For the soil pan study, soils from Source SS21 were initially characterized in terms of contaminant levels, nutrient levels, and soil chemical and physical characteristics. Because PCB levels were found to be very low, the soils were spiked with reagent-grade Arochlor 1260 at concentrations of 30 and 300 mg/kg. Triplicate soil pans were prepared for five different treatments, including three types of controls and the two levels of PCB-spiked soils treated with the vendor's product. The concrete study included two types of controls and the vendor's product applied to triplicate concrete specimens taken from an area previously determined to be contaminated with PCBs.
Pollutant degradation in the soil pans and concrete specimens was monitored over a 2-month study period. The soils were analyzed weekly for pH, oxidation-reduction (redox) potentials, and total PCBs using an immunoassay method. Soil samples were also collected each month for analysis of Arochlor PCBs by EPA SW846 Method 8081, congener-specific PCBs by high resolution gas chromatography, and plant-available nitrate, ammonium, and orthophosphate. The concrete samples were sampled monthly and analyzed for Arochlor PCBs using EPA SW846 Method 8081. A series of I soil batch extractions were also performed to determine whether the vendor's additive increases the solubility of PCBs in water.
The bench-scale study failed to demonstrate that PCB levels in either soils spiked with 30 mg/kg of Arochlor 1260 or PCB-contaminated concrete specimens could be reduced to the target level of 5 mg/kg total PCB through biological treatment during a 2-month incubation period. A statistically significant decline in PCB concentration (26%) was observed for one soil control treatment. None of the concrete treatments showed statistically significant changes over the 2 -month treatment period.
Vendor's Independent Tests-During this study, the vendor received several sample splits of the 300 mg/kg treated soil material (Treatment SE) so that they could conduct independent analytical tests. Their tests confirmed that significant PCB destruction had not occurred through Day 47. At that time, the vendor began their own bench-scale test on the soil splits in an attempt to hasten the biodegradation process. They reported that upon drying, the soil samples hardened irreversibly.
They speculated that the hard-setting nature of the soil might limit the exchange of oxygen into the soil matrix, preventing the biodegradation process from proceeding to a desired second stage of aerobic metabolism. The vendor subjected the soil sample to a surfactant treatment as an attempt to increase the solubility of the PCBs and make them more bioavailable. Afterwards, the soil was reinoculated with live additive and mixed thoroughly to establish aerobic conditions. After incubating 7 days, the sample was analyzed for Arochlor PCBs. The vendor claims that the PCB concentration was reduced to 60 mg/kg after this treatment.
4.6 Conclusion-Biological dechlorination under anaerobic conditions is typically a slow process. The bench-scale study failed to demonstrate that PCB levels in soils spiked with 30 mg/kg of Arochlor 1260 or in PCB-contaminated concrete specimens could be reduced to 5 mg/kg during the 67 day incubation period. The test protocol followed by the vendor and that followed by this study were different so there is no data from this study to verify the vendor's claim. |
John Halverson |
| 9/12/1996 |
Meeting or Teleconference Held |
EPA's Meeting summary of the September 12, 1996 meeting-Decisions reached by Air Force (AF), U.S. Environmental Protection Agency (EPA), and Alaska Dept. Environmental Conservation (ADEC).
1. AF/EPA/ADEC agree that institutional controls (ICs) are necessary to ensure that contaminated shallow groundwater aquifer is not used. There is now a basewide prohibition (AF please cite) on use of the shallow aquifer which appears to be an adequate IC, therefore no additional ICs area required specific to OU3. OU3 ROD will note the need for ICs and the existence of the basewide ICs and groundwater monitoring program, and that since they are in place, no further action is necessary under the OU3 ROD.
In summary, the ROD will say:
a. All sources have been addressed;
b. No current receptors for contaminated groundwater;
c. No potential receptors in OU3 areas;
d. Potential receptors are in OU5 area, which has a remedy in place to deal with them, plus ICs and a monitoring program;
e. Basewide ICs and groundwater monitoring are in place and will continue until MCLs have been achieved.
2. AF/EPA/ADEC will research whether the actions that have taken place at SD52, SD16, etc. allow for unrestricted use. If not, some ICs may be necessary. This includes consideration of whether deep contamination remains at levels which would pose unacceptable risk in the event of future excavation, and if so, whether some ICs should be added to protect in the event of such an occurrence.
3. In addition, ADEC raised the question of ICs on deep soils with high concentrations (didn't show risk because no current exposure/receptors; concern is for proper handling/disposal in event of future excavation). |
John Halverson |
| 9/16/1996 |
Document, Report, or Work plan Review - other |
EPA comments on OU3 ROD which have not been addressed and summary of decision reached at a September 12, 1996 meeting.
5 Year Review: The purpose and focus of the 5 Year Review described in the draft ROD is not clear. Since SS21 soils will be remediated to levels which allow for unrestricted use, 5 Year Reviews will only be necessary for OU3 soils if the early actions elsewhere in OU3 (SD52, etc.) left contaminants in place above levels that would allow for unrestricted use. Based on the plan for addressing groundwater we discussed, there should be no need for a review of groundwater under the OU3 ROD either. If groundwater is NOT addressed as we discussed, there MAY be a need for a review.
Groundwater: Since constituents in groundwater remain above MCLs, the ROD must clearly explain why No Further Action is appropriate. OSWER Directive 9355.0-30 "Role of the Baseline Risk Assessment in Superfuend Remedy Selection Decisions" states the following: "Where the cumulative carcinogenic risk to an individual based on reasonable maximum exposure for both current and future land use is less than 10-4 and the non-carcinogenic hazard quotient is less than 1, action is GENERALLY NOT warranted UNLESS there are adverse environmental impacts. However, if MCLs or non-zero MCLGs are exceeded, action is generally warranted."
Since MCLs are exceeded in groundwater associated with OU3, more explanation is required in this ROD to justify a No Further Action decision. As we discussed, this could be done by adding ALL of the following explanation to the draft ROD:
a. MCLs are exceeded, thus some action, specifically Institutional Controls and Monitoring, is warranted;
b. All known sources have been removed (provide details in Chapter 3);
c. There are no current receptors of contamianted groundwater in OU3;
d. Potential receptors downgradient are already being addressed by the OU5 ROD and OU5 actions which have taken place;
e. Basewide Institutional Controls are already in place to prohibit use of the contaminated shallow aquifer and prevent future use (provide citation);
f. Groundwater is now and will contiue to be monitored as part of the Basewide Monitoring Program. The Safe Drinking Water Act is relevant and appropriate ARAR for this decision and includes the monitoring parameters and cleanup goals that will be used in the Basewide Monitoring Program;
g. Thus, No Further Action is necessary for groundwater in the OU3 ROD.
ADEC expressed a concern that there should be some provision to ensure testing and proper disposal of contaminated subsurface soil in the event of development. Due to the nature of the contamination (Fuels) , this does not appear necessary to address in this ROD, but rather should be worked out between the Air Force and ADEC.
Section 4.0 needs to be better explained: Why action is necessary. That OU3 sources of contamination to groundwater have been identified and addressed. That there are no current or expected future receptors of contaminated groundwater within OU3 (due to basewide ICs, citing something other than the OU5 ROD). The basis for concluding that Natural Attenuation is occurring (Are contaminants declining, or what? How long is it expected to take?). That No Further Action is necessary for groundwater, because Basewide ICs AND Monitoring are already in place and WILL continue until groundwater meets MCLs.
The Safe Drinking Water Act needs to be identified in section 5.1.2 ARARs to show it was considered, even though it is not an ARAR for the selected action. EPA suggests an explanation be added such as "The SWDA is not an ARAR for this remedy, since No Further Action is necessary for groundwater under the OU3 ROD. HOWEVER, it is the ARAR for the Basewide Monitoring Program and the groundwater actions selected in the OU5 ROD to protect downgradient receptors. If further action to protect groundwater is ever necessary, it WILL be done pursuant to the OU5 or OU6 RODs." |
John Halverson |
| 9/16/1996 |
Document, Report, or Work plan Review - other |
ADEC J. Halverson letter to USAF J. WIlliamson & L. Underbakke RE: Draft-Final ROD OU3 August 1996. We previously provided comments, in a December 11, 1995 letter, on the October 1995 draft-final ROD. A few comments are no longer relevant, since the treatability study showed bioremediation was not feasible. However the rest of the comments were not addressed & are listed again. Comments from December 11, 1995:
1) Statutory Determinations - It states a review will be conducted 5 years after completion of the remedial action. A 5-year review is required if waste is left in place. It is not clear if the review is proposed based on the PCBs at SS21, contaminants at other source areas, or both. Please clarify this issue.
2) Section 2.1, page 2-1 - The SD31 description states, "... floor drains which connected to dry wells. A dry well... designated as SD31." The current wording is not clear regarding the number of dry wells that may have been present. If only 1 dry well was present, the "s" should be removed from "wells" in the 1st sentence above, otherwise it implies that more dry wells may exist
3) Section 3.1, page 3-4 - The last paragraph states, "the list was further refined by removing affected analytes associated with analytical methods that were determined to be non-representative of site conditions..." Please clarify the meaning of this statement or reword the sentence.
4) Tables 3-1, 3-2 & 3-3 - The tables are titled "Soil Contaminants/Standards .. .", "Surface Water & Sediment Contamination/Standards ... ", & "Groundwater Contamination/Standards. . ." The associated text refers to several groups of contaminants (VOC's, SVOC's, pesticides) detected in various source areas.
However, all the contaminants described in the text are not listed in the tables. The tables should include information on all the contaminants described in the text, or the heading on the tables should be changed to state that only COCs are listed (recommend adding the other contaminants to the tables to more clearly present information on residual contaminants).
5) Table 3-4 should include a footnote defining "SS", which is used in the exposure frequency for the current, on-site, occupational scenario.
6) Section 4.0 - The 1st sentence states, "The following subsections discuss.. . & presents...." The "s" should be removed from presents.
9) Section 5.0, page 5-2 - The last sentence refers to a 5-year review. If implementation of the remedial action results in the agreed upon cleanup level being met, a 5-year review should not be necessary for soil at SS21.
10) General Comment - The ROD does not include any reference to the PCB contaminated cement at SS21 or its disposal. This should be added to the document.
11) General Comment - The ROD refers to ICs to limit use of groundwater from the shallow aquifer. It does not include any reference to ICs on management of soil that may be excavated from OU3 source areas during future construction projects. Ultimately, NFAS decisions will be approved for each source area based on calculated risks in current & estimated future exposure scenarios.
However, these decisions do not address identification, characterization, & management of residual contaminated soil that may be excavated during future development. Real estate records or other appropriate land records should include documentation on where contaminated soil has been identified & remains in the ground. This would help planners identify potential contaminated areas when proposing development on the base & may help in avoiding future compliance problems or contractor downtime.
New Comments-1) As discussed briefly on September 12, data collected after completing the RI still needs to be compiled & submitted. Providing this in a tech. memo, as an addendum to the RI, would be acceptable.
2) Section 2.1, page 2-1: The word "were" in the 1st sentence should be changed to "are".
3) Section 2.2, page 2-2: The 1st paragraph states the site was divided into 7 operable units (OUs). The 2nd paragraph describes 6 OUs & states that the ROD for OU6 will finalize all CERCLA activities at the base. The text should describe what happened with OU7. Also, please see EPA's comment on rewording the sentence on finalizing CERCLA activities.
4) Section 3.2, page 3-10: The last sentence, which states, 'Therefore, OU3 will not cause an impact to sensitive receptors", should be deleted & replaced with a statement that the modeling results will be compared with monitoring data to ensure negative impacts to sensitive receptors do not occur.
5) Section 5.1.2, page 5-2: The Safe Drinking Water Act MCLs & MCLGs & the Alaska Air Quality Control Regulations 18 AAC 50.050(f) for dust suppression should be listed as relevant & appropriate.
6) Response to comments page III-ii: The response to comment #7: all soil with PCBs > 5 mg/kg is present within the top 6" of soil . Please verify this statement is true. |
John Halverson |
| 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 |
| 11/1/1996 |
Document, Report, or Work plan Review - other |
Memorandum from ADEC J. Halverson to L. Underbakke USAF RE: OU3 ROD comments on final dated October 1996. As discussed during our telephone conversation on October 31, additional amendments are necessary to finalize the OU3 ROD for signature. A list of comments on the document are included below. Please contact me at 269-7545, if you have any questions regarding these comments.
1) Section 2.3, the second to last sentence to clarify, suggest revising it to state, "Soil with contaminants that pose a potential threat to the public will be removed, transported, and disposed in an appropriate facility."
2) Section 2.3, the last sentence: As discussed during our telephone conversation, a few sentences should be included describing how the institutional control restricting shallow
groundwater use was established and how it is implemented. Simply stating the control is through the Air Force Base Facility Board does not provide sufficient detail to people who are
not familiar with that Board and how it works.
3) Section 3.0: The first sentence states that the section identifies areas which may require remedial action. The second sentence should be revised to state something like, "One area was
identified for remedial response based on the risk..."
4) Section 3.1.1, the third paragraph undei SS21 Soil Results: The first sentence should be changed to state, "Also in 1996, a concrete pad and loading dock were removed..."
5) Table 3-2:
a) The cleanup standard for 4,4-DDD in groundwater needs to be verified and properly footnoted;
b) The pesticide standard listed needs to be verified (it appears the value isted is based on an industrial scenario, rather than residential);
c) The surface water quality criteria should still be included as guidelines;
d) The basis for the values that are currently listed is the surface water cleanup guidelines islunclear (other than for lead which is footnoted to be a background value).
6) Table 3-3: Please include the frequency of detection column and verify that correct values listed under it.
7) Tables 3-1, 3-2 and 3-3 should include all compounds of concern described in the text.
8) Table 3-5: The footnote should explain why noncarcinogenic risks are not included in the table.
9) Section 5.0: The bullet which states, "After cleanup, the site will be available for unrestricted use" should be deleted from the "specific components of the selected remedy" section. Similar wording is already included under the "specific benefits" portion of the section at the bottom of page 5-1. Also, please amend the bullet to clarify that shallow groundwater use would still be restricted, as we discussed.
10) Section 5.1.2: The last bullet under th, ARARs should state, ".. 40 CFR 300.440 is applicable for the transportation and disposal..."
11) Section 5.1.4: The last sentence should be reworded to state, "The off-site disposal alternative does not utilize treatment, but the only effective treatment alternative for this site is very costly and does not result in a significant reduction in risk relative to excavation and off-site disposal." Either method would result in the same reduction in risk if the same cleanup levels are achieved, however, on-site treatment would be much more costly. |
John Halverson |
| 12/19/1996 |
Update or Other Action |
Action Memorandum sent by the USAF regarding the Agency review of the OU3 Remedial Design. Letter confirms the decision made during the RPM meeting on 12/5/1996. RPMs from EPA, AF, ADEC, agreed that the EPA and ADEC only require the 90% design review for the OU3 SS21 Remedial Action. This was agreed upon because the excavation and off site disposal of the PCB contaminated soil at SS21 is not a complicated design. ADEC concurred. |
Louis Howard |
| 1/3/1997 |
Cleanup Level(s) Approved |
Excavation and off-site disposal of soils containing PCBs greater than 5 mg/kg. GW is impacted in the shallow aquifer beneath Operable Unit 3 (OU3) and institutional controls (ICs) exist at the base for the shallow aquifer and GW monitoring of selected wells within OU3 is included as part of OU5 GW monitoring. The ICs against use of the shallow GW at the base is through the EAFB facility board and the Base Comprehensive Plan (BCP). Projects and other activities are reviewed during the planning stage to ensure compliance with BCP and also undergo an environmental review to ensure compliance with GW use restrictions. After cleanup, site SS21 soil will be available for unrestricted use. As a requirement of previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to restrict the use of the shallow aquifer in the outwash plain on the base.
The risks for contaminated groundwater beneath OU 3 are above maximum contaminant levels (MCLs) however; institutional controls exist at the base for the shallow aquifer and groundwater monitoring of selected wells located within OU 3 is included as part of OU 5 groundwater monitoring. Therefore, action is not required for contaminated groundwater beneath OU 3 under this ROD. The institutional control against use of shallow groundwater at the base is through the Elmendorf Air Force Base Facility Board.
ARARS: The Safe Drinking Water Act is not an ARAR for this remedy since no further action is
necessary for contaminated groundwater under the OU 3 ROD. However, it is the ARAR for the groundwater actions selected in the OU 5 ROD to protect groundwater receptors. If further action to protect groundwater (beneath OU 3) is ever necessary, it will be done pursuant to the OU 5 or OU 6 RODs. |
Louis Howard |
| 1/3/1997 |
CERCLA ROD Approved |
The Record of Decision (ROD) reflects changes for the selected remedy in the Proposed Plan (PP) from in-situ biological treatment to excavation & off-site disposal of soils containing PCBs greater than 5 mg/kg. The presence of PCBs in the soil at SS21 resulted in a risk of 1.1 x 10-4. This risk occurs for a future 30-year resident, the most conservative scenario*. For all the other areas at OU 3, the risk is below 10-6 or within the range of 10.5 to 10-6. Risks did not exceed 1 x 10-4 in groundwater at OU 3. This risk is based on future residents drinking & bathing with the shallow-aquifer groundwater in the area for 30 years.
*However, the risks at receptor SD52 are calculated under the most likely scenario which is that of a construction worker in contact with subsurface soils. This risk is calculated as excess cancer risks conservatively assumed for l year of exposure during on-site construction work.
In order to determine a cleanup level for PCBs at SS21, a risk evaluation was performed using the same conservative assumptions. Under site conditions, a cleanup level of 5 ppm PCBs was determined to be comparable to the EPA standard default risk of 1 ppm (EPA PCB superfund guidance for unrestricted residential use). This means that if SS21 contains less than 5 ppm PCBs, the site will be available for unrestricted use. By comparing contaminant concentrations in soil with cleanup standards, risk-based criteria, & interim remediation goals, the COC for soil at OU 3 is PCBs at site SS21. Although other contaminants at other sites at OU3 exceeded interim remediation goals or action levels, the resulting risks were considered acceptable.
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NOTE TO FILE: OSWER DIRECTIVE 9355.0-30 (Don. R. Clay) Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions states-Where the cumulative carcinogenic site risk to an individual based on reasonable maximum exposure for both current & future land use is less than 10(-4) & the non-carcinogenic hazard quotient is less than 1, action generally is not warranted unless there are adverse environmental impacts. HOWEVER, IF MCLs or non-zero MCLGs ARE EXCEEDED, ACTION IS WARRANTED.
Chemical specific standards that define acceptable risk levels (e.g., non-zero MCLGs, MCLs) also may be used to determine whether an exposure is associated with an unacceptable risk to human health or the environment & whether remedial action under Section 104 or 106 is warranted. For ground water actions, MCLs & non-zero MCLGs will generally be used to gauge whether remedial action is warranted.
EPA uses the general 10(-4) to 10(-6) risk range as a "target range" within which EPA strives to manage risks as part of a Superfund cleanup. Once a decision has been made to make an action, EPA has expressed a preference for cleanups achieving the more protective end of the range (i.e., 10(-6)), although waste management strategies achieving reductions in site risks anywhere within the risk range may be deemed acceptable by the EPA risk manager. Furthermore, the upper boundary of the risk range is not a discrete line at 1 x 10(-4), although EPA generally uses 1 x 10(-4) in making risk management decisions. A specific risk estimate around 10(-4) may be considered acceptable if justified based on site-specific conditions, including any remaining uncertainties on the nature & extent of contamination & associated risks. Therefore, in certain cases EPA may consider risk estimates slightly greater than 1 x 10(-4) to be protective.
When an ARAR for a specific chemical (or in some cases a group of chemicals) defines an acceptable level of exposure, compliance with the ARAR will generally be considered protective even if it is outside the risk range (unless there are extenuating circumstances such as exposure to multiple contaminants or pathways of exposure). Conversely, in certain situations EPA may determine that risks less than 1 x 10(-4) are not sufficiently protective & warrant remedial action.
Where current conditions have not resulted in a release posing risks that warrant action but there is a significant possibility that a release will occur that is likely to result in an unacceptable risk, remedial action may also be taken. The significance of the potential future release may be evaluated in part based on the quantities of material at the site & the environmental setting.
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Groundwater (GW) is impacted in the shallow aquifer in the East Intersource Area (includes SD31, SD16 & SS21): TCE 140 ug/L, PCE 9.37 ug/L, Benzene 6.17 ug/L, Methylene Chloride 6.43 ug/L, bis(2-ethylhexyl)phthalate 1,150 ug/L, Cadmium 25.6 ug/L & Lead 26 ug/L. Institutional controls (ICs) exist at the base for the shallow aquifer & GW monitoring of selected wells within OU3 is included as part of OU5 GW monitoring. |
Lynn Kent |
| 1/3/1997 |
Institutional Control Record Established |
Although organic constituents (e.g., TCE) are present above Maximum Contaminant Levels (MCLs) in the shallow groundwater aquifer beneath OU 3, the concentrations are generally low, there
are no current receptors, and institutional controls at the base exist for the shallow aquifer to prevent use. Metals were also identified above MCLs; however, based on a comparison of metals concentrations in the shallow-aquifer groundwater beneath OU 3 and background concentrations, the metals were determined to be at or below background concentrations (Section 3.3).
All sources of groundwater contamination in OU 3 have been or will be addressed as a part of
the remedial action at OU 3. No current receptors exist for groundwater at the base due to institutional controls. As a requirement of previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to restrict the use of the shallow aquifer in the outwash plain on the base These restrictions are enforced through the Base Comprehensive Plan (OU 3 groundwater contamination is included in these ICs). Projects and other activities are reviewed during the planning stage to ensure compliance with the Base Comprehensive Plan. In addition, construction projects and other activities also undergo an environmental review. This review helps ensure compliance with groundwater use restrictions. For these reasons, it was determined remedial action is not required for groundwater contamination at OU 3.
ARARS: The Safe Drinking Water Act is not an ARAR for this remedy since no further action is
necessary for contaminated groundwater under the OU 3 ROD. However, it is the ARAR for the groundwater actions selected in the OU 5 ROD to protect groundwater receptors. If further action to protect groundwater beneath OU 3 is ever necessary, it will be done pursuant to the OU 5 or OU 6 RODs. |
Louis Howard |
| 1/3/1997 |
Long Term Monitoring Established |
Operable Unit 3 ROD Requirements: " Although organic constituents (e.g. , TCE) are present above Maximum Contaminant Levels (MCLs) in the shallow groundwater aquifer beneath OU 3, the concentrations are generally low, there are no current receptors, and institutional controls at the base exist for the shallow aquifer to prevent use. Metals were also identified above MCLs. The Safe Drinking Water Act is not an ARAR for this remedy, since no further action is necessary for groundwater under the OU 3 ROD. However, it is the ARAR for the groundwater action selected in the OU 5 ROD to protect groundwater receptors. If further action to protect groundwater is ever necessary, it will be done pursuant to the OU 5 or OU 6 RODs."
Operable Unit 3 groundwater will be monitored as a part of the Base wide monitoring program and OU5 monitoring. |
Louis Howard |
| 3/28/1997 |
Update or Other Action |
OU 3 Scope of Work Remedial Design/Remedial Action (RD/RA) received. This document is the Scope of Work (SOW) for the remedial design/remedial action (RDIRA) at Elmendorf Air Force Base, Alaska Operable Unit 3 (OU 3), site SS21. OU 3 includes three areas of investigation, including a shop waste disposal site (SDI6), Building 32-060 (SD31), and a former polychlorinated biphenyl (PCB) transformer storage facility (SS21). The U.S. Air Force (USAF) conducted a remedial investigation/feasibility study (RI/FS) at OU 3 which was finalized in March 1995.
The Record of Decision (ROD) for 0 U 3 was signed by all parties by 3 January 1997.
The selected remedial action for OU 3 SS21 is excavation and off site disposal of soil at Source
Area SS21 containing levels of PCBs at or above 5 parts per million (ppm). As a requirement of
previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to restrict the use of the shallow aquifer in the outwash plain on the base [which includes GW beneath OU 3]. These restrictions are enforced through the Base Comprehensive Plan. Projects and other activities are reviewed during the planning stage to ensure compliance with the Base Comprehensive Plan. In addition, construction projects and other activities also undergo an environmental review. This review helps ensure compliance with groundwater use restrictions.
The rationale for selection of the remedial action to be conducted at 0U 3, as well as a detailed discussion of the remedial activities is presented in the OU 3 ROD. This SOW presents the work to be accomplished and the schedule of all activities required to implement the remedial action at 0U 3. The SOW includes information required by the Elmendorf Federal Facilities Agreement (FFA).
For this remedial action, all soil at or above the cleanup level (estimated to be 200 cubic yards) would be excavated and shipped to a disposal facility which is acceptable for disposal of CERCLA waste under the Off-site Disposal Rule (40 CFR 300.440). The cleanup level was determined to be 5 ppm based on a risk evaluation using site conditions. Field screening of the soil will be performed to guide the work and indicate apparent completion. Soil will be excavated until cleanup goals are met. The cleanup will be considered complete once statistically valid confirmation sampling demonstrates that cleanup goals have been achieved. Clean soil would be backfilled to restore the original grade of the site.
No institutional controls will be necessary for soil at SS21 after the completion of remedial action. As a requirement of previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to restrict the use of the shallow aquifer [which includes GW beneath Operable Unit 3] in the outwash plain on the base. These restrictions are enforced through the Base Comprehensive Plan. Projects and other activities are reviewed during the planning stage to ensure compliance with the Base Comprehensive Plan. In addition, construction projects and other activities also undergo an environmental review. This review helps ensure compliance with groundwater use restrictions. |
Louis Howard |
| 5/30/1997 |
Update or Other Action |
100% Design for the design analysis summary received. Soil excavation will be conducted at locations identified in the drawings to an initial depth of 6 inches. The area of excavation was determined based on analytical data collected during the RI, and is based upon quantifiable data. Quantifiable data are those generated by analytical methods approved by the U.S. Environmental Protection Agency (U.S. EPA). These include SW846 methods, and do not include field screening methods. The excavation, as designed, will remove soil known to contain PCBs in concentrations greater than or equal to 5 mg/kg, based on quantifiable test results.
Excavations will be conducted in accordance with the contractor's approved work plan. Material
will be excavated using methods that minimize soil mixing or techniques that would otherwise dilute existing PCB concentrations. Material will be loaded directly into transport containers staged at Source SS21, and soil profiling conducted on the material placed in the containers.
All samples will be analyzed for PCBs using Method SW846-8080. To avoid significant field
delays during excavation, a sample turn-around-time of 48 hours is specified. Because there are 37 sample locations identified on the drawings, methods were sought to reduce analytical costs. The U.S. EPA guidance document Verification of PCB Spill Cleanup by Sampling and Analysis (U.S. EPA, 1985) suggests sample compositing be conducted to reduce the required number of analytical tests, thereby significantly reducing costs.
For SS21, relatively low levels of PCB concentrations in soils and a relatively low cleanup level suggested using a COMPOSITE sample group size of FOUR (4). This corresponds to a composite sample cleanup level of 1.78 mg/kg, based on a cleanup level of 5 mg/kg in an individual sample. |
Louis Howard |
| 8/29/1997 |
Update or Other Action |
Elmendorf AFB has completed the remedial design for cleaning up contaminated soil in Spill Site 21 (SS21), located on the southwest end of the base. This cleanup plan is in accordance with the 1990 Federal Facilities Agreement between the U.S. Air Force, the Environmental Protection
Agency (EPA), and the Alaska Department of Environmental Protection Conservation (ADEC).
SS21, a former storage area for transformers, some of which contained polychlorinated biphenyl (PCB) oil, is the final area of Operable Unit 3 (OU3) requiring cleanup. PCBs are a suspected carcinogenic compound formerly used in transformers. Soil contaminated with PCBs at SS21 is limited to shallow soils in a defined area and is not expected to migrate to other areas.
REMEDIAL DESIGN PLAN
In March 1995, the OU3 Remedial Investigation of contamination and Feasibility Study of cleanup options were completed. In June 1995 the Proposed Plan for Remedial Action was issued. The Record of Decision selecting the final remedial action for OU3 was signed in January 1997.
The cleanup is scheduled to begin and be completed within the summer of 1998. The affected soil will be removed and sent for disposal to an EPA-approved facility outside Alaska. The expected volume of soil is 200 cubic yards. Clean soil will be brought to the site to restore the area to its original grade once the removal action is complete.
The main features of the remedial design plan (illustrated in the diagram at right) include:
-A temporary chain link fence (now in place) to restrict access to the site until the soil is removed.
-All soil with a PCB concentration of more than 5 parts per million (ppm) will be removed and shipped to a disposal facility.
-Confirmation sampling will be performed to make sure all the affected soil has been removed.
-The removal of soil and sampling will be performed during the summer of 1998.
-After the soil has been removed, the area will be available for unrestricted use. |
Louis Howard |
| 2/24/1998 |
Site Added to Database |
QA\QC revealed that this action was not previously added. |
Louis Howard |
| 4/10/1998 |
Update or Other Action |
Field Sampling Plan received. Operable Unit 3, Source SS21 (a former transformer storage site) is located at the intersection of Elm Street and Nutmeg Boulevard on Elmendorf Air Force Base, Alaska.
A remedial investigation by the government revealed that the soil at this location is contaminated with PCBs that resulted from leaking transformers. Laboratory analyses suggest that the contamination is limited to the top 6 inches of soil in a 240 cubic yard area that was used for transformer storage.
Under contract to Elmendorf Air Force Base, Oil Spill Consultants, Inc. (OSCI) will excavated
soil from the contaminated area until the residual PCB level is equal to or less than 5 mg/kg.
OSCI will also perform the following work:
• Remove two 180 ft. by 50 ft. concrete pads and haul the pieces to Elmendorf AFB concrete landfill.
• Place excavated PCB contaminated soil in containers provided by the government.
• Collect soil samples from the excavated area to confirm that residual PCB levels in the
excavation area are equal to or less than the 1.78 mg/kg cleanup goal for composite samples and 5 mg/kg cleanup goal for discrete samples.
• Collect samples and prepare chemical profiles for PCB contaminated soil.
• Restore project site by placing 2 inches of topsoil, planting grass and 100 trees.
The following data quality objectives (DQO) are established for this project:
• DQO-1: Establish Sampling Grid. OSCI will retain the services of a registered surveyor to
establish the sample points shown in Figure 3.
• DQO-2: Laboratory Confirmation for Residual PCB Levels in Site Excavation. For this DQO,
both composite and discrete samples will be collected from the sample points established
under 000-1. The laboratory results will be used to determine if the cleanup goal has been
achieved or if additional soil must be excavated.
DQO-3: Density Analysis for Containerized Soil. As authorized by Modification No. 0001,
soil density will be used to limit the weight of each container of PCB contaminated soil to
17 tons.
|
Louis Howard |
| 4/21/1998 |
Site Ranked Using the AHRM |
Ranking action added now because it was not added when the site was originally ranked. |
Louis Howard |
| 5/4/1998 |
Update or Other Action |
Surveying begins to delineate the grid area for sampling PCBs at SS21 source area. Removal by excavation to 5 mg/kg total PCBs and disposal off site at an out of state EPA approved and permitted landfill facility is the chosen method of cleanup. Confirmation sampling in May 1998 showed that additional excavation was required to achieve cleanup levels. July 1998 excavation and confirmation sampling at the source area showed cleanup levels had been achieved for the majority of the source area. However, 3 areas (5D, 6A, and 6D) exceeded the ROD specified cleanup goal. A third round of excavation was completed in September 1998. Confirmation sampling indicated that the PCB concentrations present at the site were less than the cleanup level of 5 mg/kg. A total of 95.1 tons of PCB contaminated soil was excavated and removed from the site during the remedial action.
Hazardous waste manifests showed the PCB soils were sent to Envirosafe Services of Idaho Inc. in Grand View ID 83624 EPA ID IDD073114654. The waste was disposed of by landfilling in an approved TSCA landfill by the company in the summer and fall of 1998. |
Louis Howard |
| 10/1/1998 |
CERCLA ROD Periodic Review |
OU3 is located in the southwestern portion of ElmendorfAFB. This OU consists of three sources and one receptor area.SS21 is an area where transformers containing polychlorinated biphenyls (PCBs) were stored. The OU3 ROD was signed in January 1997 and the selected remedy focused on the PCB soil contamination at SS21. Major components of the cleanup action at SS21 include:
* A chain-link fence will be temporarily installed to restrict access to the area until the
PCB-contaminated soil can be excavated and disposed of off-site.
* All soil with PCB concentrations in excess of 5 parts per million (ppm) will be
excavated and shipped to an EPA-approved disposal facility in the Lower 48.
* After cleanup is complete, SS21 will be available for unrestricted land use. HOWEVER, as
required by other RODs, institutional controls that prohibit the use of the shallow aquifer
in the outwash plain will remain in effect for groundwater in this OU.
Operable Unit 3. Response actions at OU3 are underway and are approximately 95 percent complete. Excavation of the PCB-contaminated soils at SS21 commenced on April 27, 1998 and over the next four months approximately 980 tons of PCB-contaminated soil was excavated and shipped to an EPA-approved disposal facility in the Lower 48. Sampling was performed upon completion of the excavation of the PCB-contaminated soil and results confirmed cleanup goals outlined in the ROD were achieved. Upon completion of excavation activities, the area was backfilled and graded to the original elevations, and then landscaped. The temporary fence, which was installed in 1996 to restrict access to the site, has been removed. The only outstanding issue remaining, is the receipt of the certification of disposal from the EPA-approved disposal facility.
The selected remedy for OU3 is protective and compliant with ARARs. All remedial activities
at SS21 were accomplished in accordance with the remedial design. Based upon confirmation samples obtained at the conclusion of the SS21 remedial action, PCB contamination remaining on site is less than 0.6 ppm, well below the ARARs outlined in the ROD. The successful completion of the SS21 remedial action allows for unlimited use and unrestricted exposure to the site. No future five-year reviews of OU3 will be conducted because the remedial action was successfully completed as planned.
HOWEVER, groundwater needs to be addressed still. 1995 RI/FS Table 4-17 Summary of GW Screening Results from OU3 East GW area soil borings for SS21 TCE sample results exceeding the 5 ug/L cleanup level for the following: SB-02 5.5 ug/L and SB-10 10 ug/L (MCL=5 ug/L). The TCE levels observed in groundwater from wells at Source Area SS21 (MW5 and MW6) are likely associated with downgradient migration of groundwater from source SD16, with a possible contribution of low levels of TCE from the soil at SS21.
There are currently no receptors of groundwater in OU3 East (SD16, SS21 SD31). Groundwater modeling results indicate that contaminant plumes within OU3 will naturally attenuate before reaching sensitive receptors within OU5. Groundwater monitoring data will be collected from monitoring wells at OU3 to ensure that groundwater from OU3 will NOT impact the sensitive receptors at OU5. The Basewide groundwater monitoring plan describes the monitoring locations, sampling frequency, analytical parameters, and reporting format. Since potential future impacts will be monitored, no further action is planned for this site. (Section 7.6.5 Conclusions) |
Jennifer Roberts |
| 10/27/1998 |
Update or Other Action |
07/98-09/98 quarterly progress report received. Chain link fence temporarily installed to restrict access to area until the PCB contaminated soil is excavated and disposed of off site at a permitted treatment, storage, disposal facility in the Lower 48. Cleanup level is 5 mg/kg or less of PCBs in soil. Highest level at SS21 is 467 mg/kg.
Contractor excavated 1,980,000 pounds of PCB contaminated soil. Originally it was estimated that 250 cubic yards of soil was to be excavated, but in the end it turned out to be closer to 660 cubic yards. The Defense Reutilization and Marketing Office disposed of the PCB soils for $1, 032,000. Fence removed and site backfilled, graded and landscaped with trees and grass. EPA and ADEC inspected the site on 9/29/98. |
Louis Howard |
| 1/6/1999 |
Document, Report, or Work plan Review - other |
EPA Comments Remedial Action Report OU3 Final: Page 1-1 Since this Remedial Action is complete and no Long-Term Remedial Action is required, the opening paragraph of the Introduction section should be revised slightly to reflect the fact that the “remedial action selected in the 1997 Record of Decision is complete, performance standards have been achieved, the site has been inspected, and no further response action is anticipated.”
Page 1-2 The paragraphs describing the activities at SD31 and Cherry Hill Ditch are very brief and leave the reader with some questions. At a minimum a reference should be added to direct the reader to the document(s) containing the details of what contamination was found and the actions performed to address the contamination.
Page 1-2 In the fifth paragraph, after reference is made to “detectable concentrations of solvents and fuel constituents in groundwater”, EPA believes it would be accurate and helpful to state that the sources are attributed to upgradient releases which have been or are being addressed pursuant to other Operable Units and/or response authorities.
Page 3-1 In Section 3.3 or elsewhere , the document should identify the disposal facility in the lower 48 where the PCB-contaminated soil was disposed.
Page 3-2 In Section 3.3.2 it would be appropriate to reiterate or at least refer to the results of the bioremediation treatability study. While this is described previously and is not, strictly speaking, a component of the Remedial Action, it was a “Lesson Learned” that readers looking for might otherwise miss.
Page 6-1 Section 6.0, the “Summary of Project Costs” should be explained somewhat to summarize the reasons for the increase in Actual costs from the ROD estimate. Suggested additions include some description of the assumptions that went into the original cost estimate, a summary paragraph explaining the discovery that the extent/volume of contaminated soils was greater than anticipated and likely reasons why, and a slightly more detailed breakout of the corresponding Actual costs. |
Louis Howard |
| 1/11/1999 |
Document, Report, or Work plan Review - other |
L. Underbakke (USAF) commented on the Remedial Action Report: Sec 3.3.2, P-1, Page 3-2 This paragraph does not make sense. The high hit of 427 was confirmed. If it is hard to delineate the amount of contamination of PCB at a former transformer site then say so.
Sec 3.3,
P-3&4, Page 3-5 The sampling grid used…These paragraphs do not make sense. Cut to the chase. RI/RD and treatability study did not reveal the high levels of contamination.
Sec 4.0,
P-1, Page 4-1 Include the EPA and ADEC inspection of the sites as complete.
Tables 6-1 & 6-2 Table 6-1 needs to have the same line item as 6-2. Explain that these was more contaminated soil found after the RA was underway thus increasing the cost.
|
Louis Howard |
| 1/12/1999 |
Update or Other Action |
10/98-12/98 Quarterly progress report received. Five year review document signed by EPA and ADEC that the remedial action has been completed at the site and is protective of human health and the environment. Disposal certification for PCB contaminated soil received. Since residual levels are less than 1 mg/kg for PCBs, site use is unrestricted and site closed out. However, as a requirement for other RODs, institutional controls that prohibit use of the shallow aquifer in the outwash plain will remain in effect for groundwater in this operable unit. No further quarterly reports for OU3. |
Louis Howard |
| 3/31/1999 |
Document, Report, or Work plan Review - other |
AFCEE Review comments Remedial Action Report OU3 Final. This is a very well written report, with only minor changes noted below.
Note that a recent directive from AFCEE states that henceforth documents submitted must adhere to the United States Geologic Survey “Suggestions to Authors;” specifically, that when used as a noun “ground water” (two words) is the proper form, and that when used as an adjectival noun (i.e. ground-water hydrology) a hyphen is inserted between the words.
Insert in the appropriate Appendices the following missing documentation:
• Copies of chain-of-custody forms for the analytical samples.
• Copies of PCB-contaminated soil waste manifests.
Sec 3.3, P-3, Page 3-2 Insert a brief statement indicating that all other PCB Aroclor constituents analyzed for were below method detection limits.
Table 3-1, Pages-3-3& 3-4 Report analytical results with the same number of significant figures as reported in the laboratory data reports.
Sec 3.4, P-1, L-1 Page 3-5 Replace last sentence of paragraph as follows: “No further response actions are required at this site.”
|
Louis Howard |
| 11/18/1999 |
Document, Report, or Work plan Review - other |
JAG Air Force comments (J. Klasen):
Sec 3.3.2, Page 3-2 The section is vague, particularly the first paragraph. Clarify why the confirmation sampling varied so much from the sampling results from the Remedial Investigation (RI). It appears to me that the sampling results were different because many spills of PCB transformer fluid left a contaminated surface area of from six square inches to three square feet. The small footprints left by the contamination made it statistically difficult to find the highest PCB concentrations using the RI sampling grid pattern developed under EPA guidelines. Many small contaminated areas simply fell between the sampling points. The primary lesson here for me is that RI sampling can easily underestimate by ten fold the amount of actual PCB contaminated soil where numerous small spills are involved.
Table 3-1, Page 3-3 This is confusing. There is no need to give such lengthy sample location codes of up to 21 characters. The code numbers should be condensed by at least deleting the characters 98-OU3-SS21 which are common to all the sample locations. Also there should be a footnote explaining what the code letters A, B, C, and D indicate. Additionally, it would be helpful if we inserted a map next to the table to show where the samples were taken. Finally consider explaining in a footnote why there was no additional sampling at a location where results exceeded the cleanup level. |
Louis Howard |
| 11/30/1999 |
Conditional Closure Approved |
Remedial Action Report finalized which showed that all PCB contaminated soils associated with site were excavated, stored/transported to a properly licensed Treatment Storage, Disposal facility in lower 48. 5 mg/kg PCB cleanup level achieved at site.
The results of the RI at SS21 verified that PCBs were the principal soil contaminants in this area. The most likely potential source of this contamination was the leaking of PCB-laden oil from electrical transformers. Transformers are no longer stored at the site. Low levels of volatile organic compounds (VOC) and semi-volatile organic compounds (SVOC) were detected at SS21 and may also be related to the transformer oils. Pesticides were present across the site as well as across the base. In addition, isolated levels of arsenic and lead were detected at
SS21. The presence of these metals may also berelated to the transformer oils.
There were three stages of the remedial action. The first stage was conducted from 4 to 16
May, 1998. During the first stage, additional temporary fencing was erected prior to commencing the remedial action to fully enclose the work area. Two concrete pads located on site were excavated and disposed of. Additionally, the top six inches (240 cubic yards) of PCB-contaminated soil were excavated according to the design specifications and directly loaded into Government-furnished transport containers.
Excavation sampling was performed to ensure that all soils containing PCBs in concentrations
greater than or equal to 5 mg/kg were excavated. Excavation samples were analyzed for PCBs using
Method SWS46-S0S2. Sample results are presented in Table 3-1. Appendix B contains all analytical
data. Concentrations for Aroclor-1260 in samples collected during the May excavating/sampling event ranged from non-detect to 427 mg/kg.
The maximum Aroclor-1260 concentration detected in previous sampling events was 27.6 mg/kg. Because of the increased concentration, a limited review of analytical data collected as part of the confirmation sampling was conducted. A memorandum summarizing the data review and possible explanations for the significant increase in Aroclor-1260.concentrations is included in Appendix C. All other PCB isomers (i.e., Aroclor compounds) were below method detection limits.
The sampling grid used to confirm achievement of negotiated cleanup levels for SS21 was developed using U.S. EPA guidance. This grid used a larger sampling interval than that used during the remedial investigation, but detected PCBs at significantly higher levels than reported during the RI. Therefore, previous sampling events were likely performed using more stringent investigation techniques than recommended by U.S. EPA guidance.
The probability of finding discrete locations of contamination using discrete sampling points can be decreased through more frequent sampling (i.e., decreased grid intervals). However, increasing the number of samples must be weighed against the total site remediation cost. The use of U.S. EPA guidance to conduct the remedial action at SS21 is appropriate.
Based on the May excavation sampling results, additional soil was excavated in July. This round
of excavation involved excavating areas that had May 1998 Aroclor-1260 concentrations that exceeded 5 mg/kg. Confirmation sampling was conducted on 16 and 23 July 1998. Aroclor-1260 concentrations ranged from non-detect to 47.4 mg/kg. Three areas (5D, 6A, and 6D) exceeded the ROD-specified cleanup goal.
A third round of excavation was completed in September 1998. Confirmation sampling indicated that Aroclor-1260 concentrations present at the site were less than the regulatory cleanup goal
of 5 mg/kg.
A total of 951.1 tons of PCB-contaminated soil was excavated and removed from the site during
the remedial action. Following excavation, all excavated areas were backfilled with clean fill and compacted to restore the site to match the existing grade. Material used for backfill was obtained from a borrow pit located within Government-controlled land. The fence was removed from the site. SS21 was hydroseeded, and 300 trees were planted along the perimeter of the site.
|
Louis Howard |
| 10/5/2000 |
Site Number Identifier Changed |
Changed work plan from X1 to X9 to reflect presence of PCBs. |
Former Staff |
| 1/31/2003 |
Update or Other Action |
2002 Annual Report Basewide Environmental Monitoring Program Draft January 2003 received. Note to file under:
ARARs
This data-reporting category addresses groundwater constituents for each individual program area
specifically identified as COCs. The original list of cleanup levels for each program area is listed in Table 2-1. These chemical-specific cleanup levels were identified either in decision documents prepared for these sites (FFA program areas) or as contaminants which were found to significantly exceed cleanup levels where groundwater COCs were not specifically identified in previous investigations (SERA and Taxiway “N” program areas). Source documents that listed cleanup levels are referenced in Section 4.
Within the context of the Basewide Program, the list of COCs for each program area can change
as data are continuously evaluated and the quality of data improves with new methods. For instance, as natural attenuation occurs, select constituents will reach cleanup levels and additional monitoring for that constituent will not be required unless mandated by a regulatory agreement. Specifically, if a COC is below cleanup levels for two consecutive sampling rounds, sampling for that COC can be discontinued.
Similarly, if cleanup levels for all COCs in a given analytical method are met across an entire program area, analysis using that method in that program area will no longer be required. An exception to the above guideline is made for OU 5. Because OU 5 serves as the downgradient receptor for most of the other program areas, COCs will not be eliminated from OU 5 unless the COC in question has been similarly eliminated first from all upgradient program areas. |
Louis Howard |
| 6/7/2013 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 73767 name: OU3 SS21 PCB Storage |
Louis Howard |
| 12/20/2013 |
Document, Report, or Work plan Review - other |
Staff provided comments on the draft 4th 5 Year Review report.
1-6 Table 1-1 OU 3 Status - The text states that this Operable Unit (OU) is not included as part of the Fourth Five-Year Review because sites are closed.
This is not entirely correct for ongoing GW monitoring for OU3.
The Record of Decision (ROD) for OU3 states the following regarding GW:
Assessment of the Site
“The risks for GW beneath OU 3 are above maximum contaminant levels (MCLs) however; institutional controls exist at the base for the shallow aquifer & GW monitoring of selected wells located within OU 3 is included as part of OU 5 GW monitoring. Therefore, action is not required for GW under this ROD. The institutional control against use of shallow GW at the base is through the Elmendorf Air Force Base Facility Board.”
& at the
Selected Remedy
After cleanup, site SS21 soil will be available for unrestricted use. As a requirement of previously signed RODs for Elmendorf Air Force Base, institutional controls have been established to restrict the use of the shallow aquifer in the outwash plain on the base.”
5.1.2 ARARs
“The Safe Drinking Water Act is not an ARAR for this remedy since no further action is necessary for GW under the OU 3 ROD. However, it is the ARAR for the GW actions selected in the OU 5 ROD to protect GW receptors [Due to OU3 GW monitoring requirements being transferred to OU5 & the Basewide Monitoring Program]. If further action to protect GW is ever necessary, it will be done pursuant to the OU 5 or OU 6 RODs.”
1995 OU3 Remedial Investigation (RI)
Identification of Contaminant Sources
“In general, VOC contamination in GW at OU 3 East is widespread & covers a significant areal extent. Sporadic detections of contaminants in many occasions make it difficult to establish trends of contamination, & therefore, potential sources for the observed contamination. A few exceptions to this observation are discussed below.
The levels of VOCs (primarily TCE & benzene) detected in GW samples from wells installed at source SD16 suggest that there is a potential source or sources of contamination at source SD16, primarily in the eastern half of the area. These sources could potentially include the former waste disposal trenches, vehicle maintenance activities & the underground storage tanks located in the northeast corner of SD16 (approximately upgradient from well MW13). Further contributions to contamination could come from source SS21, located downgradient from source SD16.”
The GW at OU3 was observed to be above maximum contaminant levels (MCLs) please see Table 7-8 1995 OU3 RI. The monitoring for this contamination was transferred to the Basewide GW Monitoring for OU5.
The 1995 OU3 RI states:
7.11.1 Areas Recommended for No Further Action at OU3
“The two GW areas at au 3, OU 3 east GW area & OU 3 west GW area, have carcinogenic risks in the range of 1.0E-05. However, there are currently no receptors of GW within the operable unit. A GW model performed as a part of the OU 5 investigation predicts that migration of constituents from OU 3 will naturally attenuate before reaching OU 5, causing no increased impact to sensitive receptors. Continued monitoring will be necessary to ensure that there will not be impacts outside of OU 3. A basewide GW monitoring plan has been developed & outlines the monitoring locations, sampling frequency, analytical parameters, & reporting format of the monitoring program.”
Specifically, the following monitoring wells were noted in the 1995 OU3 RI (See Tables 7-8 & 7-13) to have MCL exceedances [tetrachloroethylene (PERC), TCE, benzene, cadmium, lead] that were not attributed to laboratory contamination:
IS8-01, [OU3]MW02, MW05R, [OU3]MW11, [OU3]MW12, [OU3]MW13, W13, MW25, [OU3]MW05 & [OU3]MW-20.
Any monitoring wells & chemicals of concern associated with OU3 need to be considered as part of the 5 Year Review for OU5. Please ensure that any occupied buildings or manned structures in proximity to any VOC GW plumes that were formerly associated with OU3 are being addressed by the vapor intrusion study for OU5 GW (e.g. Fairchild Avenue Plume).
Operable Unit 3
OU 3 is not listed here, however, the GW monitoring was transferred to OU 5. VOCs were the COC in OU3’s GW. See comment regarding OU3 being transferred to OU5 with regards to GW monitoring.
1995 Basewide Support & GW Monitoring Program for OUs 3/4 Round 2
Results for OU3
Page 13 Table 2-3
MW-11: Tetrachloroethene 9.23 ug/L & Trichloroethene (TCE) 88.4 ug/L
1996 Annual Report of GW Sampling Activities, “All Results of Organic Analyses for Water Samples Site OU3 & OU4 GW Monitoring 1995”
OU3-MW-11
Page 189
Round 1
Tetrachloroethene 8.73 ug/L, TCE 98.4 ug/L
Page 208
Round 2
Tetrachloroethene 9.23 ug/L, TCE 88.4 ug/L
|
Louis Howard |
| 2/14/2019 |
Document, Report, or Work plan Review - other |
Staff commented on the five year review. PFAS investigation is needed to delineate the nature and extent of contamination at this source area (CS DB Hazard ID 2791) in Operable Unit 3. In 2016, PFOA was detected in groundwater at a concentration above the EPA HA but below the ADEC cleanup level. PFOS was detected at a concentration above the EPA HA and the ADEC cleanup level. SS021 is downgradient of AFFF #19 and could be potentially impacted by this source area contributing to the Western ST037 Groundwater Plume (12.3 The Western ST037 plume includes the former Fairchild Avenue Plume, Kenney Avenue Plume, OU3MW-25 Plume, OU5MW-02 Plume, and SP1-02 Plume (2016 Annual RA-O and Monitoring Report CERCLA Sites. May 2018).) [AFFF #7 also could be contributing to groundwater PFAS contamination). Wells nearest to OU3 SS021: OU3MW-06, OU3MW-05.
See site file for additional information. |
Louis Howard |
