Site Report: JBER-Elmendorf ST427 AFID 136 & 137 SO501

Site Name:	JBER-Elmendorf ST427 AFID 136 & 137 SO501
Address:	Hanger 4 and Engine Test CellBldgs. 8565 & 9559 Slammer Avenue, Formerly Elmendorf Air Force Base before 10/1/2010, Elmendorf AFB (JBER), AK 99506
File Number:	2101.26.100
Hazard ID:	24831
Status:	Cleanup Complete - Institutional Controls
Staff:	Ginna Quesada, 9074515960 ginna.quesada@alaska.gov
Latitude:	61.243983
Longitude:	-149.795921
Horizontal Datum:

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Site Chronology
IC / Closure Details
Documents
Associated Sites

Problems/Comments

AFID 136, 2,000 gallon JP-4, AFID 137, 2,000 gallon JP-4. The USTs and associated dispensers were removed in 1995. DRO present in soil above cleanup levels in the smear zone. Formerly Bldg 11-140 and 11-160 on "Q" Street. The project site is located between Q Street and Building 11-160. Buildings 11-140 and 11-160 are located in the northeast corner of the southwest 114 of Section 3, Township 13 North, Range 3 West, Seward Meridian, and can be found on the Anchorage A-S NE USGS Quadrangle.

Action Information

Action Date	Action	Description	DEC Staff
3/3/1993	Update or Other Action	DOD & ADEC joint Technical Memorandum of understanding signed concerning the Basewide Groundwater (gw) signed by: ADEC Jennifer Roberts RPM & USAF Joseph Williamson Chief Environmental Programs & Restoration. Due to the basewide gw study & the FY92 field work that occurred at Operable Units (OUs) 1, 2, & 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 & Record of Decision (ROD). This means addressing all gw from upgradient sources (CERCLA (ST20, Ous 3&4) & OUs 1 & portions of OU2) & 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
4/18/1995	Update or Other Action	Memorandum of agreement regarding UST closures. Based on conversation between John Mahaffey, Larry Opperman (Elmendorf) and John Halverson (ADEC). EAFB will make every effort to accomplish a clean closure of a UST removal site if possible. UST removal locations requiring cleanup will be transferred into the SERA. A list of sites requiring cleanup will be coordinated with ADEC. Presumptive remedy for contaminated UST sites in the outwash plain (now referred to as the OU5 modeling area) only will be bioventing technology. Contaminated soils exceeding the cleanup levels may be placed back into the excvation only if the site assessment (SA) indicates a need for further cleanup. Contaminated UST sites not in the outwash plan will require further investigation to determine appropriate cleanup options. We will make every attempt possible to assure new USTs or new ASTs are not installed in any way that would hamper access for future cleanup. The project will first accomplish removal of all the USTs. SA information will be used to prrioritize actions using existing funds. Additional funding will be requested to complete cleanup if available. Sites not addressed for cleanup due to exhausted funding will be placed into the SERA Phase IV.	John Halverson
6/13/1995	Site Added to Database		Former Staff
6/13/1995	Leaking Underground Storage Tank Release Confirmed - Petroleum	LUST Site created in CSP for source area ID 77287	Former Staff
6/13/1995	Leaking Underground Storage Tank Cleanup Initiated - Petroleum		Former Staff
4/12/1996	Underground Storage Tank Site Characterization or Assessment	UST closure assessment delivery order no. 0006 Bldg. 11-140 & 11-160. Tank and pipe decommissioning were completed on June 13, 1995 for a 2000 gallon jet fuel UST (tank 136) and a 2000 gallon gasoline UST (tank 137). Approximately 39 cubic yards of potentially impacted soil were returned to the resulting excavation (4/18/1995 MOA ADEC & EAFB) after field screening suggested that clean closure was uncertain. Soil remaining in the eastern end of tank 136 excavation exceeded the GRO level B criteria (533 mg/kg GRO) and DRO below the tank 136 dispenser was found to be 4,090 mg/kg. The 0.7 ppm headspace (PID) concentration measured in Sample 3lOSL does not correspond with the elevated DRO concentration of 4,090 mg/kg. Mr. Tom Walker of the USACE was on site as the Tank 136 headspace samples were measured. The possibility of removing some asphalt pavement and excavating additional soil to achieve a clean closure was discussed. A "ball park" estimate that on the order of 100 cubic yards of soil would require remediation was made. Because no mechanism was in place to fund the remediation of an undetermined volume of soil, and clean closure was not certain within the constraints of Contract DACA85-92-D-001O, D.O. 0006, it was decided to use the excavated soil for backfill. The recommendation that the Building 11-160 tank location be transferred into the State-Elmendorf Environmental Restoration Agreement (SERA) for future remedial investigation and corrective action was discussed with Mr. Larry Opperman of EAFB. Using UST impacted soil as backfill for the tank excavation is permitted based on theMemorandum for Alaska Department of Environmental Conservation (MOA) summarizing the results of an April 15, 1995 UST meeting between ADEC and EAFB. (NOTE This was later rescinded as of 8/11/1995 per J. Halverson).	Louis Howard
10/17/1996	Update or Other Action	Air Force memo: Restricted Use of the Shallow Aquifer on EAFB signed by William R. Hanson P.E. GM-14 Chief Environmental Flight dated October 17, 1996 Memorandum for 3 SPTG/CEC/CEO from 3 SPTG/CEV 1) Due to the contamination & 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 & 6 which require, the aquifer remain unused. 2) Personnel in the review process within CES must be aware of these policies & review them on a recurring basis. It is imperative this restriction be recognized & observed during engineer reviews & operations.	Louis Howard
3/31/1997	Update or Other Action	AFIDs 136 & 137 SERA Phase IV ST427 Release Investigation FINAL received. In 1996, three soil borings were installed during the SERA Phase IV investigation. ST 427 is a former underground storage tank (UST) site located between Q Street and Building 11-160, south of the Old Hush House. Two steel USTs, Air Force Identification (AFIO) numbers 136 and 137, had 2000-gallon capacities and were used to store jet propulsion fuel No.4 (JP-4) and motor vehicle gasoline (mogas). UST 136 was located to the south of UST 137, and both were oriented with the primary axis east-west. ST427 is immediately downgradient from SERA IV site ST410. ST427 is an unpaved gravel area surrounded by pavement in an access road/equipment parking area adjacent to the north/south runway. The former USTs and dispenser location were discerned by the gravel area and the UST removal coordinates. No surface staining was observed at the site. Three borings were completed at ST427, including one bioventing air injection well (11-160WL01), one soil gas monitoring array (11-160PZ01), and one boring that was grouted following drilling and sampling (11-160BH01). Groundwater was encountered at approximately 27 feet below ground surface (bgs). Site soils consist of sand and gravel with fines typical to the Elmendorf outwash plain. Soil samples contained elevated ATH/PIO readings and smelled of petroleum only in the smear zone of 11-160PZ01 (344 mg/kg). It is likely that the petroleum-hydrocarbon contaminated soil detected in backfill and beneath the former USTs at ST427 was remediated through a combination of volatilization and biodegradation prior to conducting the release investigation. The relatively low concentrations of petroleum hydrocarbons detected beneath the former USTs suggest that minimal vertical contaminant migration occurred. The elevated DRO concentrations beneath the former dispenser may have been a small-volume, localized release. Based on the results of the release investigation, the USAF recommends ST427 USTs 136 and 137 for no further action, as certified on the following disposition recommendation.	Louis Howard
10/27/1998	Update or Other Action	Corrected address, input legal description	Former Staff
10/21/2002	Update or Other Action	Letter sent to Joe Williamson dissolving the State Elmendorf Environmental Restoration Agreement. The Alaska Department of Environmental Conservation (DEC) has reviewed the issue of abolishing the State Elmendorf Environmental Restoration Agreement (SERA) per your recommendation. Elmendorf Air Force Base and DEC entered into the SERA in 1992. The agreement was developed as a tool to bring the Base into compliance with Alaska's regulations addressing underground storage tanks, oil and other hazardous substance releases and solid waste. Since that time, Elmendorf has made significant progress in investigating and cleaning up historic contamination problems. Many of the sites covered by the SERA have been successfully cleaned up and closed. Cleanup is underway at the remaining sites. Additionally, Alaska has amended the regulations addressing fuel storage tanks, oil and other hazardous substance spills and solid waste. We concur with you that the SERA is no longer a necessary or beneficial. This letter serves as notice that DEC will end oversight on environmental work at Elmendorf by using the SERA. Instead, it is understood that the sites and programs formerly addressed by SERA: solid waste, underground storage tanks (UST), and oil and other hazardous substance discharges will be addressed in accordance with 18 AAC 60, 18 AAC 78 and 18 AAC 75.	Louis Howard
6/28/2004	Conditional Closure Approved	The Department has reviewed the documents associated with ST427 Bldg. 9559 and concurs that the site will not require any further remediation or site investigation. Because petroleum contaminated soil (contaminant levels higher than the Method 2 cleanup levels in Tables B1/B2 found in 18 AAC 75.341) remains at this site, the Base Master Plan needs to be updated to document the locations of residual contamination and the need to manage contaminated soil properly. The Department is basing its decision on the most current and complete data provided by the Air Force. The Department reserves its rights, under: 18 AAC 75 Oil and Other Hazardous Substances, Pollution Control regulations, 18 AAC 78 Underground Storage Tank Regulations, and Alaska Statute 46.03 to require additional investigation, cleanup, or containment if subsequent information indicates that: 1) additional contamination remains at the site which was previously undiscovered and presents an unacceptable risk to human health, safety, or welfare, or the environment; or 2) the information provided was invalid, incomplete, or fraudulent.	Louis Howard
6/28/2004	Institutional Control Record Established	Because petroleum contaminated soil (contaminant levels higher than the Method 2 cleanup levels in Tables B1/B2 found in 18 AAC 75.341) remains at this site, the Base Master Plan needs to be updated to document the locations of residual contamination and the need to manage contaminated soil properly. The Base Master Plan is used when a dig permit or construction permit is filed and verfication is conducted to identify any potential areas of contamination that the project may run into. The relatively low levels of petroleum hydrocarbons detected beneath the former UST suggest that minimal vertical contaminant migration occurred. Downgradient smear zone contamination was detected; however, this could be associated with an upgradient source such as ST410. This site is located immediately outside of the OU5 modeling area as identified in the Operational Agreement (OA) between ADEC and Elmendorf AFB signed 28 July 2002. In the OA, both parties agree that the portion of the unconfined shallow aquifer in the outwash plain has demonstrated, through modeling and sampling, the ability to naturally attenuate residual hydrocarbon contamination from most petroleum, oil, and lubricant (POL) spills in a reasonable period of time. The Elmendorf AFB Basewide Groundwater Monitoring Program will be utilized to monitor groundwater during implementation of the remedy. The site is located just outside of the OU5 Modeling Area and is approximately 1,400 feet upgradient of the Early Warning Line. The nearest downgradient monitoring well currently in the Basewide Groundwater Monitoring Program is 61-WL-02, located approximately 475 feet southwest of ST427.	Louis Howard
2/18/2005	Update or Other Action	February 18, 2005 list of sites sent which includes ST427. Well ID 61WL-02 will be sampled on an biannual basis for BTEX and DRO and PAH. Each well presented in the table submitted will be sampled in 2005 to establish baseline COC concentrations. Proposed sampling frequencies would thus take effect in 2006. An annual sampline frequency has been assigned to sites near the OU5 Bluff whereas all other sites received a biannual frequency.	Louis Howard
7/19/2005	Update or Other Action	On October 15, 1999, the Alaska Department of Environmental Conservation (ADEC) received final release investigation (RI) report for ST 426/7. ADEC has reviewed the site assessment (SA) and RI of a former 700-gallon diesel underground storage tank (UST) associate with Building 44-785. ADEC is requesting the Air Force (AF) to conduct additional RI work to further define the extent of the diesel range organic (DRO) dissolved phase plume, and delineate the vertical extent of contaminated soil within the footprint of the former UST excavation. ADEC is also requesting AF to develop a corrective action plan (CAP) to remediate the soil and groundwater (GW) contamination associated with the former UST release. Soil contamination, as high as 12,800 mg/kg DRO, was found in confirmation samples collected from the bottom of the former UST excavation, and levels over 5000 mg/kg were found in the 24 cy of stockpiled soil that was later returned to the UST excavation. Soil samples collected from borings located outside the former UST excavation had low levels of DRO contamination, indicating the petroleum release was restricted to the immediate vicinity of the UST and moved vertically from the release point. GW sampling of 4 on site monitoring wells shows DRO as high as 7.63 mg/L. Sample results from monitoring wells located outside the former UST excavation, indicate the GW outside the UST excavation area is below cleanup standards. The 1996 RI soil data indicated the soils consist of dense silts and a shallow or possible perched water table was present. Based on this information, AF has determined that their presumptive remedy, including bioventing of contaminated soils, natural attenuation and long term monitoring of the ground water plume, is not appropriate for this site.	Louis Howard
7/6/2006	Update or Other Action	2005 Annual Report Monitored Natural Attenuation of Basewide Compliance Program Wells received. Currently, the 3 CES/CEVQ is required by ADEC to monitor the degree to which certain regulated contaminants are naturally attenuating on 27 sites throughout the Base. The natural attenuation of each of these sites is being monitored by sampling and analyzing the groundwater under the contaminated areas and/or downgradient of the contaminated source. In 1996, gasoline range organics (GRO) and diesel range organics (DRO) concentrations in soil exceeded the Method Two cleanup levels at ST427. In 2005, groundwater at monitoring well 61WL-02, located hydraulically downgradient of ST427, did not have detectable concentrations of DRO or BTEX.	Louis Howard
6/20/2007	Update or Other Action	Staff reviewed and commented on the 2006 Annual Report Monitoring of Compliance Program Sites, Elmendorf Air Force Base (EAFB) dated May 2007. ADEC concurs with the recommendations to sample 427MW-IN for diesel range organics (DRO).	Louis Howard
7/5/2007	Update or Other Action	Staff reviewed and commented on the Draft Work Plan and Field Sampling Plan Compliance Program Sites, Elmendorf Air Force Base (EAFB) dated June 27, 2007. For ST427 the following well will be monitored: 427MW-IN for DRO and PAHs. ADEC has developed a technical memorandum and a Laboratory Data Review Checklist (checklist) summarizing the minimum requirements for both laboratory data packages and quality assurance (QA) summaries (data reduction, verification, evaluation, etc.). All reports submitted by the Air Force which contain analytical laboratory sample results shall contain a completed checklist and a QA summary. The latest checklist is available online at http://www.dec.state.ak.us/spar/guidance.htm#csp and must be completed, signed and dated by the firm submitting the report to ADEC. It is not to be completed by the analytical laboratory that performed the sample analysis. The summary must be included as a specific text section of the report. All laboratory results, including laboratory quality control (QC) sample results, must be reviewed and evaluated for quality, validity and usability. The text must include any effects on data validity and/or usability due to field sampling/laboratory quality control discrepancies. Upon incorporation of comments regarding the checklist, ADEC will approve the work plans.	Louis Howard
7/27/2012	Update or Other Action	Draft site closure report received. No contaminants have been detected in groundwater above ADEC 18 AAC 75.345 Table C cleanup levels for two consecutive years. Soil sampling in 1996 indicated DRO contamination remained in the smear zone above the ADEC 18 AAC 75.341 Method Two, Table B2 Under 40-Inch Zone, Migration to Groundwater cleanup level; however, no contaminants were detected above cleanup levels in the vadose zone. Due to the remaining smear zone contamination, excavation/soil movement and groundwater use restrictions will remain in place at the site. The use of the shallow aquifer for any purpose is not allowed. As long as hazardous substances remain at levels that preclude unrestricted use, groundwater development and the use of groundwater for any purpose including but not limited to drinking, irrigation, fire control, dust control, or any activity is prohibited in the shallow aquifer south of the Elmendorf Moraine. Remaining residual contamination in groundwater and the vadose zone is below regulatory standards, and site closure with institutional controls is appropriate and protective of human health and the environment.	Louis Howard
11/28/2012	Update or Other Action	The Alaska Department of Environmental (ADEC) has received the draft final closure report for review and comment for ST427 (CS DB Hazard ID 24831 ADEC File# 2101.26.100). ADEC has reviewed the document and ADEC has determined the site meets the requirements of 18 AAC 75.380(d)(1). The site has been adequately characterized under 18 AAC 75.335 and has achieved the applicable requirements under the site cleanup rules. ADEC is issuing this written determination that the cleanup is complete with institutional controls, subject to a future ADEC determination that the cleanup is not protective of human health, safety, or welfare, or of the environment.	Louis Howard
2/7/2023	Document, Report, or Work plan Review - other	DEC reviewed the 2023 Letter Work Plan Remedial Action Operations and Long-Term Management, Draft, dated January 2023. The work plan describes the site inspections, maintenance activities, and groundwater, seep, and surface water monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. The scope of work briefly summarizes the site locations, sampling/monitoring schedules, and activities such as free-product removal from monitoring wells and monitoring/maintenance activities at the Operable Unit 5 wetlands. The details regarding the procedures for the remedial action operations and long-term management activities will remain consistent with the 2021 Uniform Federal Policy Quality Assurance Project Plan (UFP-QAPP).	Ginna Quesada
4/25/2023	Document, Report, or Work plan Review - other	DEC approved the 2023 Letter Work Plan Remedial Action Operations and Long-Term Management, Final, Dated April 2023. The work plan describes the site inspections, maintenance activities, and groundwater, seep, and surface water monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. The scope of work briefly summarizes the site locations, sampling/monitoring schedules, and activities such as free-product removal from monitoring wells and monitoring/maintenance activities at the Operable Unit 5 wetlands. The details regarding the procedures for the remedial action operations and long-term management activities will remain consistent with the 2021 Uniform Federal Policy Quality Assurance Project Plan (UFP-QAPP).	Ginna Quesada
5/18/2024	Document, Report, or Work plan Review - other	DEC submitted comments regarding the 2023 Annual Remedial Action-operations And Long-term Management Report for Select State-regulated Sites Draft, Dated April 2024. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections were recommended to continue for all sites to ensure that conditions remain protective of human health and the environment. The report recommends updating land use controls (LUC) site boundaries at CG534, a ‘Cleanup Complete’ determination without institutional controls (ICs) for SS522, the removal of groundwater LUCs at SS041, and a ‘Cleanup Complete with ICs determination for TU101.	Ginna Quesada
6/25/2024	Document, Report, or Work plan Review - other	DEC approved the 2023 Annual Remedial Action-operations And Long-term Management Report for Select State-regulated Sites Final, dated June 2024. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections were recommended to continue for all sites to ensure that conditions remain protective of human health and the environment. The report recommends updating land use controls (LUC) boundaries at CG534, a ‘Cleanup Complete’ determination without institutional controls (ICs) for SS522, the removal of groundwater LUCs at SS041, and a Cleanup Complete with ICs determination for TU101.	Ginna Quesada
1/30/2025	Document, Report, or Work plan Review - other	DEC approved the 2025 Remedial Action–Operations and Long-term Monitoring Work Plan Addendum Final, dated January 2024.The work plan describes the site inspections, maintenance activities, and groundwater, seep, and surface water monitoring, activities that will be conducted at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. The scope of work briefly summarizes the site locations, sampling/monitoring activities and schedules. This workplan will remain consistent with the procedures outlined in the 2023 Letter Work Plan Remedial Action-Operations and Long-Term Management.	Ginna Quesada
5/6/2025	Long Term Monitoring Workplan or Report Review	DEC approved the 2024 Annual Remedial Action-Operations and Long-Term Management Report for Select State-Regulated Sites Final, dated May 2025. The report describes the site inspections, maintenance activities, and groundwater monitoring, at multiple sites located on Joint Base Elmendorf- Richardson (JBER), Anchorage, Alaska. Site inspections were recommended to continue for the majority of the sites to ensure that conditions remain protective of human health and the environment. DEC concurs with the recommendation to close SS522 site without ICs, discontinue groundwater sampling at TU107, and reducing the sampling frequency for some wells at TU103.	Ginna Quesada

Action Date

Action

Description

DEC Staff

3/3/1993

Update or Other Action

DOD & ADEC joint Technical Memorandum of understanding signed concerning the Basewide Groundwater (gw) signed by: ADEC Jennifer Roberts RPM & USAF Joseph Williamson Chief Environmental Programs & Restoration. Due to the basewide gw study & the FY92 field work that occurred at Operable Units (OUs) 1, 2, & 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 & Record of Decision (ROD). This means addressing all gw from upgradient sources (CERCLA (ST20, Ous 3&4) & OUs 1 & portions of OU2) & 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

4/18/1995

Update or Other Action

Memorandum of agreement regarding UST closures. Based on conversation between John Mahaffey, Larry Opperman (Elmendorf) and John Halverson (ADEC). EAFB will make every effort to accomplish a clean closure of a UST removal site if possible. UST removal locations requiring cleanup will be transferred into the SERA. A list of sites requiring cleanup will be coordinated with ADEC. Presumptive remedy for contaminated UST sites in the outwash plain (now referred to as the OU5 modeling area) only will be bioventing technology. Contaminated soils exceeding the cleanup levels may be placed back into the excvation only if the site assessment (SA) indicates a need for further cleanup. Contaminated UST sites not in the outwash plan will require further investigation to determine appropriate cleanup options. We will make every attempt possible to assure new USTs or new ASTs are not installed in any way that would hamper access for future cleanup. The project will first accomplish removal of all the USTs. SA information will be used to prrioritize actions using existing funds. Additional funding will be requested to complete cleanup if available. Sites not addressed for cleanup due to exhausted funding will be placed into the SERA Phase IV.

John Halverson

6/13/1995

Site Added to Database

Former Staff

6/13/1995

Leaking Underground Storage Tank Release Confirmed - Petroleum

LUST Site created in CSP for source area ID 77287

Former Staff

6/13/1995

Leaking Underground Storage Tank Cleanup Initiated - Petroleum

Former Staff

4/12/1996

Underground Storage Tank Site Characterization or Assessment

UST closure assessment delivery order no. 0006 Bldg. 11-140 & 11-160. Tank and pipe decommissioning were completed on June 13, 1995 for a 2000 gallon jet fuel UST (tank 136) and a 2000 gallon gasoline UST (tank 137). Approximately 39 cubic yards of potentially impacted soil were returned to the resulting excavation (4/18/1995 MOA ADEC & EAFB) after field screening suggested that clean closure was uncertain. Soil remaining in the eastern end of tank 136 excavation exceeded the GRO level B criteria (533 mg/kg GRO) and DRO below the tank 136 dispenser was found to be 4,090 mg/kg. The 0.7 ppm headspace (PID) concentration measured in Sample 3lOSL does not correspond with the elevated DRO concentration of 4,090 mg/kg. Mr. Tom Walker of the USACE was on site as the Tank 136 headspace samples were measured. The possibility of removing some asphalt pavement and excavating additional soil to achieve a clean closure was discussed. A "ball park" estimate that on the order of 100 cubic yards of soil would require remediation was made. Because no mechanism was in place to fund the remediation of an undetermined volume of soil, and clean closure was not certain within the constraints of Contract DACA85-92-D-001O, D.O. 0006, it was decided to use the excavated soil for backfill. The recommendation that the Building 11-160 tank location be transferred into the State-Elmendorf Environmental Restoration Agreement (SERA) for future remedial investigation and corrective action was discussed with Mr. Larry Opperman of EAFB. Using UST impacted soil as backfill for the tank excavation is permitted based on theMemorandum for Alaska Department of Environmental Conservation (MOA) summarizing the results of an April 15, 1995 UST meeting between ADEC and EAFB. (NOTE This was later rescinded as of 8/11/1995 per J. Halverson).

Louis Howard

10/17/1996

Update or Other Action

Air Force memo: Restricted Use of the Shallow Aquifer on EAFB signed by William R. Hanson P.E. GM-14 Chief Environmental Flight dated October 17, 1996 Memorandum for 3 SPTG/CEC/CEO from 3 SPTG/CEV 1) Due to the contamination & 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 & 6 which require, the aquifer remain unused. 2) Personnel in the review process within CES must be aware of these policies & review them on a recurring basis. It is imperative this restriction be recognized & observed during engineer reviews & operations.

Louis Howard

3/31/1997

Update or Other Action

AFIDs 136 & 137 SERA Phase IV ST427 Release Investigation FINAL received. In 1996, three soil borings were installed during the SERA Phase IV investigation. ST 427 is a former underground storage tank (UST) site located between Q Street and Building 11-160, south of the Old Hush House. Two steel USTs, Air Force Identification (AFIO) numbers 136 and 137, had 2000-gallon capacities and were used to store jet propulsion fuel No.4 (JP-4) and motor vehicle gasoline (mogas). UST 136 was located to the south of UST 137, and both were oriented with the primary axis east-west. ST427 is immediately downgradient from SERA IV site ST410. ST427 is an unpaved gravel area surrounded by pavement in an access road/equipment parking area adjacent to the north/south runway. The former USTs and dispenser location were discerned by the gravel area and the UST removal coordinates. No surface staining was observed at the site. Three borings were completed at ST427, including one bioventing air injection well (11-160WL01), one soil gas monitoring array (11-160PZ01), and one boring that was grouted following drilling and sampling (11-160BH01). Groundwater was encountered at approximately 27 feet below ground surface (bgs). Site soils consist of sand and gravel with fines typical to the Elmendorf outwash plain. Soil samples contained elevated ATH/PIO readings and smelled of petroleum only in the smear zone of 11-160PZ01 (344 mg/kg). It is likely that the petroleum-hydrocarbon contaminated soil detected in backfill and beneath the former USTs at ST427 was remediated through a combination of volatilization and biodegradation prior to conducting the release investigation. The relatively low concentrations of petroleum hydrocarbons detected beneath the former USTs suggest that minimal vertical contaminant migration occurred. The elevated DRO concentrations beneath the former dispenser may have been a small-volume, localized release. Based on the results of the release investigation, the USAF recommends ST427 USTs 136 and 137 for no further action, as certified on the following disposition recommendation.

Louis Howard

10/27/1998

Update or Other Action

Corrected address, input legal description

Former Staff

10/21/2002

Update or Other Action

Letter sent to Joe Williamson dissolving the State Elmendorf Environmental Restoration Agreement. The Alaska Department of Environmental Conservation (DEC) has reviewed the issue of abolishing the State Elmendorf Environmental Restoration Agreement (SERA) per your recommendation. Elmendorf Air Force Base and DEC entered into the SERA in 1992. The agreement was developed as a tool to bring the Base into compliance with Alaska's regulations addressing underground storage tanks, oil and other hazardous substance releases and solid waste. Since that time, Elmendorf has made significant progress in investigating and cleaning up historic contamination problems. Many of the sites covered by the SERA have been successfully cleaned up and closed. Cleanup is underway at the remaining sites. Additionally, Alaska has amended the regulations addressing fuel storage tanks, oil and other hazardous substance spills and solid waste. We concur with you that the SERA is no longer a necessary or beneficial. This letter serves as notice that DEC will end oversight on environmental work at Elmendorf by using the SERA. Instead, it is understood that the sites and programs formerly addressed by SERA: solid waste, underground storage tanks (UST), and oil and other hazardous substance discharges will be addressed in accordance with 18 AAC 60, 18 AAC 78 and 18 AAC 75.

Louis Howard

6/28/2004

Conditional Closure Approved

The Department has reviewed the documents associated with ST427 Bldg. 9559 and concurs that the site will not require any further remediation or site investigation. Because petroleum contaminated soil (contaminant levels higher than the Method 2 cleanup levels in Tables B1/B2 found in 18 AAC 75.341) remains at this site, the Base Master Plan needs to be updated to document the locations of residual contamination and the need to manage contaminated soil properly. The Department is basing its decision on the most current and complete data provided by the Air Force. The Department reserves its rights, under: 18 AAC 75 Oil and Other Hazardous Substances, Pollution Control regulations, 18 AAC 78 Underground Storage Tank Regulations, and Alaska Statute 46.03 to require additional investigation, cleanup, or containment if subsequent information indicates that: 1) additional contamination remains at the site which was previously undiscovered and presents an unacceptable risk to human health, safety, or welfare, or the environment; or 2) the information provided was invalid, incomplete, or fraudulent.

Louis Howard

6/28/2004

Institutional Control Record Established

Because petroleum contaminated soil (contaminant levels higher than the Method 2 cleanup levels in Tables B1/B2 found in 18 AAC 75.341) remains at this site, the Base Master Plan needs to be updated to document the locations of residual contamination and the need to manage contaminated soil properly. The Base Master Plan is used when a dig permit or construction permit is filed and verfication is conducted to identify any potential areas of contamination that the project may run into. The relatively low levels of petroleum hydrocarbons detected beneath the former UST suggest that minimal vertical contaminant migration occurred. Downgradient smear zone contamination was detected; however, this could be associated with an upgradient source such as ST410. This site is located immediately outside of the OU5 modeling area as identified in the Operational Agreement (OA) between ADEC and Elmendorf AFB signed 28 July 2002. In the OA, both parties agree that the portion of the unconfined shallow aquifer in the outwash plain has demonstrated, through modeling and sampling, the ability to naturally attenuate residual hydrocarbon contamination from most petroleum, oil, and lubricant (POL) spills in a reasonable period of time. The Elmendorf AFB Basewide Groundwater Monitoring Program will be utilized to monitor groundwater during implementation of the remedy. The site is located just outside of the OU5 Modeling Area and is approximately 1,400 feet upgradient of the Early Warning Line. The nearest downgradient monitoring well currently in the Basewide Groundwater Monitoring Program is 61-WL-02, located approximately 475 feet southwest of ST427.

Louis Howard

2/18/2005

Update or Other Action

February 18, 2005 list of sites sent which includes ST427. Well ID 61WL-02 will be sampled on an biannual basis for BTEX and DRO and PAH. Each well presented in the table submitted will be sampled in 2005 to establish baseline COC concentrations. Proposed sampling frequencies would thus take effect in 2006. An annual sampline frequency has been assigned to sites near the OU5 Bluff whereas all other sites received a biannual frequency.

Louis Howard

7/19/2005

Update or Other Action

On October 15, 1999, the Alaska Department of Environmental Conservation (ADEC) received final release investigation (RI) report for ST 426/7. ADEC has reviewed the site assessment (SA) and RI of a former 700-gallon diesel underground storage tank (UST) associate with Building 44-785. ADEC is requesting the Air Force (AF) to conduct additional RI work to further define the extent of the diesel range organic (DRO) dissolved phase plume, and delineate the vertical extent of contaminated soil within the footprint of the former UST excavation. ADEC is also requesting AF to develop a corrective action plan (CAP) to remediate the soil and groundwater (GW) contamination associated with the former UST release. Soil contamination, as high as 12,800 mg/kg DRO, was found in confirmation samples collected from the bottom of the former UST excavation, and levels over 5000 mg/kg were found in the 24 cy of stockpiled soil that was later returned to the UST excavation. Soil samples collected from borings located outside the former UST excavation had low levels of DRO contamination, indicating the petroleum release was restricted to the immediate vicinity of the UST and moved vertically from the release point. GW sampling of 4 on site monitoring wells shows DRO as high as 7.63 mg/L. Sample results from monitoring wells located outside the former UST excavation, indicate the GW outside the UST excavation area is below cleanup standards. The 1996 RI soil data indicated the soils consist of dense silts and a shallow or possible perched water table was present. Based on this information, AF has determined that their presumptive remedy, including bioventing of contaminated soils, natural attenuation and long term monitoring of the ground water plume, is not appropriate for this site.

Louis Howard

7/6/2006

Update or Other Action

2005 Annual Report Monitored Natural Attenuation of Basewide Compliance Program Wells received. Currently, the 3 CES/CEVQ is required by ADEC to monitor the degree to which certain regulated contaminants are naturally attenuating on 27 sites throughout the Base. The natural attenuation of each of these sites is being monitored by sampling and analyzing the groundwater under the contaminated areas and/or downgradient of the contaminated source. In 1996, gasoline range organics (GRO) and diesel range organics (DRO) concentrations in soil exceeded the Method Two cleanup levels at ST427. In 2005, groundwater at monitoring well 61WL-02, located hydraulically downgradient of ST427, did not have detectable concentrations of DRO or BTEX.

Louis Howard

6/20/2007

Update or Other Action

Staff reviewed and commented on the 2006 Annual Report Monitoring of Compliance Program Sites, Elmendorf Air Force Base (EAFB) dated May 2007. ADEC concurs with the recommendations to sample 427MW-IN for diesel range organics (DRO).

Louis Howard

7/5/2007

Update or Other Action

Staff reviewed and commented on the Draft Work Plan and Field Sampling Plan Compliance Program Sites, Elmendorf Air Force Base (EAFB) dated June 27, 2007. For ST427 the following well will be monitored: 427MW-IN for DRO and PAHs. ADEC has developed a technical memorandum and a Laboratory Data Review Checklist (checklist) summarizing the minimum requirements for both laboratory data packages and quality assurance (QA) summaries (data reduction, verification, evaluation, etc.). All reports submitted by the Air Force which contain analytical laboratory sample results shall contain a completed checklist and a QA summary. The latest checklist is available online at http://www.dec.state.ak.us/spar/guidance.htm#csp and must be completed, signed and dated by the firm submitting the report to ADEC. It is not to be completed by the analytical laboratory that performed the sample analysis. The summary must be included as a specific text section of the report. All laboratory results, including laboratory quality control (QC) sample results, must be reviewed and evaluated for quality, validity and usability. The text must include any effects on data validity and/or usability due to field sampling/laboratory quality control discrepancies. Upon incorporation of comments regarding the checklist, ADEC will approve the work plans.

Louis Howard

7/27/2012

Update or Other Action

Draft site closure report received. No contaminants have been detected in groundwater above ADEC 18 AAC 75.345 Table C cleanup levels for two consecutive years. Soil sampling in 1996 indicated DRO contamination remained in the smear zone above the ADEC 18 AAC 75.341 Method Two, Table B2 Under 40-Inch Zone, Migration to Groundwater cleanup level; however, no contaminants were detected above cleanup levels in the vadose zone. Due to the remaining smear zone contamination, excavation/soil movement and groundwater use restrictions will remain in place at the site. The use of the shallow aquifer for any purpose is not allowed. As long as hazardous substances remain at levels that preclude unrestricted use, groundwater development and the use of groundwater for any purpose including but not limited to drinking, irrigation, fire control, dust control, or any activity is prohibited in the shallow aquifer south of the Elmendorf Moraine. Remaining residual contamination in groundwater and the vadose zone is below regulatory standards, and site closure with institutional controls is appropriate and protective of human health and the environment.

Louis Howard

11/28/2012

Update or Other Action

The Alaska Department of Environmental (ADEC) has received the draft final closure report for review and comment for ST427 (CS DB Hazard ID 24831 ADEC File# 2101.26.100). ADEC has reviewed the document and ADEC has determined the site meets the requirements of 18 AAC 75.380(d)(1). The site has been adequately characterized under 18 AAC 75.335 and has achieved the applicable requirements under the site cleanup rules. ADEC is issuing this written determination that the cleanup is complete with institutional controls, subject to a future ADEC determination that the cleanup is not protective of human health, safety, or welfare, or of the environment.

Louis Howard

2/7/2023