Site Report: USGS Government Hill Site

Site Name:	USGS Government Hill Site
Address:	132/140 East Manor Avenue, Anchorage, AK 99501
File Number:	2100.38.325
Hazard ID:	2743
Status:	Cleanup Complete - Institutional Controls
Staff:	IC Unit, 9074655229 dec.icunit@alaska.gov
Latitude:	61.229329
Longitude:	-149.881375
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

Contamination was identified when UST heating oil tanks were removed (1997 Phase II). Drywell soils contain 5 ppm PCBs, petroleum, low level HVOCs and metals. Groundwater impacted by DRO. Lots 1, 2, and 3, Block K, North Addition #4 of Original Townsite Subdivision. In 1998 during the Phase III investigation MW-1, MW-2, and MW-3 installed. BTEX ND in soil samples. TCE in one soil sample at 0.0235 mg/kg at 12.5-14.5 ft bgs in MW-1. DRO in one soil sample at 283 mg/kg at 40-42 ft bgs in MW-3. Groundwater – DRO at 14.3 mg/l in MW-2 and 2.37 mg/l in MW-3. Cleanup 2000: Excavation of drywell and soil. No exceedances in Confirmation samples. One soil boring, TH1, had TCE at 0.029 at 4-6 ft bgs and 0.0289 at 8-10 ft bgs. Excavation of 4 test pits. DRO at 325 and 408 in TP at UST #2 Additional Investigation 2001: Two upgradient wells installed, three borings. Wells had BTEX in smear zone, no exceedances in GW samples from upgradient. Onsite well MW-2 had DRO at 2.9 mg/l Limited Cleanup 2002: Removed benzene contaminated soil from Tank #3 excavation. Confirmation samples indicate all benzene-impacted soil has been removed. DRO in MW-2 at 4.1 mg/l, no benzene. 2007 GW sampling: Wells dry in January. Sampled in June, MW-2 had DRO at 2.15 mg/l. 2008 GW sampling: Monitoring well #2 was sampled July 18, 2008 and October 3, 2008. In July DRO was found to be 20.5 mg/l. In September of 2008 efforts were made to reduce the possible contamination of the groundwater by 'air lifting' the sediment from the bottom of the monitoring well and re-developing the monitoring well for the October sampling event. The sample from October resulted in a DRO level of 18.8 mg/l.

Action Information

Action Date	Action	Description	DEC Staff
2/7/1997	Update or Other Action	Phase 1 Environmental Site Assessment 132/140 East Manor Avenue Anchorage, Alaska, dated February 1997 and submitted by Environmental Health Seciences-Alaska and Shannon & Wilson. Potential sources of contamination identified, including two former Quonset hut reportedly used for vehicle maintenance, three USTs and a dry well	Grant Lidren
3/5/1998	Site Added to Database	Phase II assessment received October, 1997 identifying contamination.	Jim Frechione
3/5/1998	Update or Other Action	Interim Action performed at the site.	Jim Frechione
3/27/1998	Update or Other Action	DEC completed review of the October 1997 Follow-up Underground Storage Tank Release Assessment Report. Four soil borings were advanced, soil samples collected and B-4 completed as a groundwater monitoring well. Groundwater contained 1.6 mg/l DRO and 0.32 mg/l methalene chloride. Investigation of a former dry well identified soil contamination DRO-6,000 mg/kg, RRO-26,000 mg/kg, PCB's 5 mg/kg and eleveated metals not attributed to background. Additional work required.	David Pikul
8/4/1998	Meeting or Teleconference Held	Meeting at USGS between USGS, ADEC, Shannon and Wilson to discuss additional site work.	David Pikul
8/4/1998	Update or Other Action	Site visit conducted by ADEC.	David Pikul
9/2/1998	Site Characterization Workplan Approved	Phase III Soil and Groundwater Assessment Workplan review. ADEC approved the workplan subject to the conditions listed in the comment letter.	David Pikul
1/15/1999	Update or Other Action	LC 14693060 established.	David Pikul
1/29/1999	Update or Other Action	DEC completed review of the report: Phase III Soil and Groundwater Assessment of the USGS Facility at 132/140 East Manor Avenue, Anchorage (Government Hill). Three monitoring wells were installed and soil and groundwater collected for laboratory analysis.	David Pikul
7/19/1999	Update or Other Action	ADEC's January comment letter faxed to Bill Fitzpatrick of USGS as he informed ADEC that he did not have the letter.	David Pikul
11/2/1999	Site Ranked Using the AHRM	Not previously ranked.	David Pikul
11/16/1999	Update or Other Action	A letter was issued to USGS stating that a considerable amount of time has passed since a letter was sent to their agency and requested USGS to indicate their intentions regarding the property.	David Pikul
5/16/2000	Meeting or Teleconference Held	Meeting with RP (USGS) to discuss remaining issues and work plan development.	David Pikul
7/27/2000	Update or Other Action	ADEC issued a reminder letter to USGS regarding work plan submittal to address outstanding issues.	David Pikul
8/4/2000	Update or Other Action	ADEC conducted a site visit to inspect the newly installed fence that was to restrict access to the drywell and excavated soils left on the ground surface. The fence is free standing, 8' x 8' chain-link enclosed dog kennel. Its placement did not enclose the soils removed from the dry well that are situated on the ground surface. The RP was notified by e-mail of the site status.	David Pikul
9/18/2000	Meeting or Teleconference Held	ADEC met with RP's consultant (Shannon and Wilson) to discuss site activities to be conducted without an ADEC approved workplan. Driller and excavator scheduling was short notice and did not allow for ADEC review prior to work activities. ADEC verbally concurred with the basics of the workplan and will review ASAP.	David Pikul
9/29/2000	Interim Removal Action Approved	Site visit conducted during drywell excavation, direct haul soil transport and disposal approval given.	David Pikul
10/2/2000	Site Characterization Workplan Approved	ADEC issued comment letter to site characterization work plan submitted, approval given, however, an amendment was requested to investigate pipe from drywell.	David Pikul
10/4/2000	Update or Other Action	Site visit conducted. Use of down-hole camera indicates that the pipe from the drywell may go into the sewer. AWWU verification requested by ADEC.	David Pikul
12/5/2000	Update or Other Action	Cost Recovery Referral Memorandum issued to Department of Law.	David Pikul
1/16/2001	Update or Other Action	Received Additional Investigation and Limited Cleanup report, prepared by Shannon and Wilson.	Scott Pexton
4/3/2001	Site Characterization Report Approved	Letter sent to Bill Fitzpatrick of USGS with approval of report entitled "Additional Investigation and Limited Cleanup" prepared for the USGS by Shannon and Wilson, Inc.	Scott Pexton
4/3/2001	Record of Decision	ADEC signed Record of Decision regarding alternative cleanup levels for soil using Method Three. The default foc and hydraulic gradient parameters were modified by ADEC to calculate these levels. Since the levels are different than those proposed by USGS (and their consultant), they shall be afforded the option to collect additional data from the site to be considered in establishing alternative cleanup levels. As a condition of establishing alternative cleanup levels, ADEC requires the installation of groundwater monitoring wells north of the site within the road right-of-way to evaluate on-site transport of contaminants from adjacent property. In addition, ADEC requests another groundwater sample event from monitoring wells MW-2 and MW-3 with samples analyzed for BTEX and DRO. The MW-2 sample should also be analyzed for methylene chloride. Following the review of the analytical data from these samples, ADEC shall evaluate the need for additional sampling and/or other cleanup actions.	Scott Pexton
4/3/2001	Cleanup Level(s) Approved	ADEC approved Method Three alternative soil cleanup levels as documented in Record of Decision. Cleanup levels approved were 0.03 mg/kg for benzene, 700 mg/kg for DRO, 0.02 mg/kg for methylene chloride, and 0.05 for trichloroethylene.	Scott Pexton
4/12/2001	Site Number Identifier Changed	Site Number Identifier Changed this date.	Former Staff
6/14/2001	Update or Other Action	Received faxed copy of Workplan for Additional Investigation prepared by Shannon and Wilson.	Scott Pexton
6/20/2001	Site Characterization Workplan Approved	Letter sent to Bill Fitzpatrick of USGS with conditional approval of workplan. Conditions include: field work tasks must be completed by August 15, 2001; at least two soil samples collected from each monitoring well soil boring will be submitted for laboratory analysis of DRO, BTEX, and HVOs; and, soil samples will be collected and submitted for DRO/RRO analysis at the same locations as the two soil samples collected for analysis for total organic carbon.	Scott Pexton
8/14/2001	Update or Other Action	ADEC received copy of letter from Department of Law indicating receipt of a check from the U.S. GSA for cost recovery (Bill #CO15427).	Scott Pexton
1/2/2002	Update or Other Action	Received Additional Investigation report prepared by Shannon and Wilson. Two groundwater monitoring wells (MW-4 and MW-5) were installed upgradient of MW-2 and sampled. Analytical results of samples from MW-4 and MW-5 indicated that BTEX, DRO, and RRO were undetected at the method detection limit. One of the conclusions in the report was that "the results of the investigation indicate that an upgradient source of contamination from Monitoring Well MW-2 is unlikely and the possible source remains unknown."	Scott Pexton
2/12/2002	Site Characterization Report Approved	Letter sent to Bill Fitzpatrick of USGS with approval of site characterization report based on information provided in the "Additional Investigation, 132/140 East Manor Avenue" report prepared by Shannon and Wilson, Inc. ADEC concurred with the recommendation to excavate the benzene-impacted soils at the former Tank 3 area for transport to the Alaska Soil Recycling facility in Anchorage for thermal treatment. The action will require ADEC approval of a cleanup plan prepared in accordance with 18 AAC 75.360. Based on the information provided, ADEC concluded that groundwater results have adequately demonstrated that RRO, benzene, toluene, ethylbenzene, total xylenes, methylene chloride, and trichloroethylene did not exceed applicable groundwater cleanup levels. Therefore, ADEC does not require further groundwater sampling for these chemicals in the monitoring wells installed to evaluate groundwater at this site. With respect to DRO in groundwater, sampling results have adequately demonstrated that DRO did not exceed applicable cleanup levels at monitoring wells MW-1, MW-4, and MW-5. Therefore, in accordance with 18 AAC 75.345(h), ADEC will discontinue the requirement for groundwater monitoring at monitoring wells MW-1, MW-4, and MW-5. These monitoring wells may be decommissioned. ADEC concluded that DRO in groundwater did not exceed the applicable cleanup level during October 2001, but did exceed the cleanup level during previous sampling events at monitoring wells MW-2 and MW-3 within Lot 3. Based on the information provided, the concentration trend of DRO in groundwater appears to be stable and decreasing. However, ADEC requested another groundwater sampling event to collect and analyze DRO in groundwater from monitoring wells MW-2 and MW-3. The report suggested that the DRO contamination of 1,500 mg/kg in soil previously sampled at soil boring B-4 be allowed to naturally attenuate. The report suggested that because the soil contamination was located below the water table at 38 feet and was not observed above the water table, that no further action may be appropriate. ADEC may consider this type of request after the cleanup and monitoring actions discussed above are completed, provided an institutional control is established for the property in accordance with 18 AAC 75.375. In accordance with the cleanup operation requirements of 18 AAC 75.360, a cleanup plan was requested by May 1, 2002. The cleanup plan should provide detailed specifications of the proposed soil removal action and groundwater sampling at MW-2 and MW-3. The plan should also include a soil confirmation sampling and analysis plan to confirm that remaining soil after excavation and removal meets applicable cleanup levels. The plan should include a schedule for conducting fieldwork, monitoring, and submittal of a final cleanup report. The site cleanup must be conducted or supervised by a qualified person.	Scott Pexton
4/24/2002	Update or Other Action	ADEC received a letter from the Department of Law indicating that a check was received from USGS for cost recovery (Bill # CO25145).	Scott Pexton
5/10/2002	Update or Other Action	ADEC received Workplan for Limited Cleanup and Groundwater Monitoring, prepared by Shannon & Wilson, Inc. The primary purpose is to excavate and remediate benzene-impacted soil from the former Tank 3 excavation and to collect groundater samples from monitoring wells MW-2 and MW-3.	Scott Pexton
5/20/2002	Cleanup Plan Approved	Letter with plan approval sent to John Spielman of Shannon & Wilson, Inc. (copy to Bill Fitzpatrick of USGS).Benzene-impacted soil will be excavated from former excavation area of Tank #3. Soil will be transported for thermal treatment to the Alaska Soil Recycling facility in Anchorage. Groundwater samples will be collected from monitoring wells MW-2 and MW-3 for DRO lab analysis. Monitoring wells MW-1, MW-4, and MW-5 will be decommissioned. Approval letter had a request to submit the final cleanup report to ADEC by July 15, 2002.	Scott Pexton
8/1/2002	Update or Other Action	Limited Cleanup and Groundwater Monitoring report with this date submitted by Shannon & Wilson	Grant Lidren
8/14/2002	Meeting or Teleconference Held	Meeting with USGS rep Bill Fitzpatrick and Shannon&Wilson consultant, John Spielman. Was given a copy of the latest report to review.	Lynne Bush
8/15/2002	Meeting or Teleconference Held	Site visit.	Lynne Bush
10/8/2002	Update or Other Action	Telephone conversation w Fitpatrick about long-term monitoring and IC issues.	Lynne Bush
10/9/2002	Update or Other Action	Follow-up on IC issues - sent copy of draft guidance to Mr. Fitzpatrick.	Lynne Bush
5/5/2003	Update or Other Action	Letter to Fitzpatrick asking for information	Lynne Bush
5/6/2003	Update or Other Action	Fitzpatrick will be sending in a long-term monitoring work plan and information to be used to complete a ROD/NEC for this site.	Lynne Bush
1/29/2004	Update or Other Action	File number changed from CS80.01 to 2100.38.325	Former Staff
8/16/2004	Update or Other Action	File tranferred to Juneau office	Sarah Cunningham
2/13/2007	Update or Other Action	Corrected 3/27/1998 and 1/29/99 entries to reflect administrative file.	Shannon Oelkers
6/24/2007	Update or Other Action	File sent to Anchorage, PM changed to O'Connell.	Bill O'Connell
6/25/2007	Site Characterization Workplan Approved	Approved work plan to sample MW-2.	Bill O'Connell
7/23/2007	Site Characterization Report Approved	Received 2007 groundwater monitoring report. One sample was collected from monitoring well MW2 which contained DRO at 2.15 mg/l.	Bill O'Connell
8/30/2007	Exposure Tracking Model Ranking		Bill O'Connell
10/9/2007	Site Characterization Workplan Approved	Reviewed work plan for groundwater monitoring at MW-2. Samples will be collected infall 2007 and spring 2008 and analyzed for DRO.	Bill O'Connell
2/7/2008	Site Characterization Report Approved	Groundwater sampling report dated December 17, 2007 submitted by Shannon & Wilson and recieved by the ADEC on this date. One sample was collected, on October 24, 2007, from monitoring well MW2 which contained DRO at 0.940 mg/L	Grant Lidren
2/8/2008	GIS Position Updated	Updated using Arc GIS SPAR_StatewideLocator (ArcReader)	Grant Lidren
1/6/2009	Document, Report, or Work plan Review - other	Received January 5, 2009 from Shannon & Wilson the Groundwater Sampling, 132/140 East Manor Avenue report that was completed November 2008. Monitoring well #2 was sampled July 18, 2008 and October 3, 2008. In July DRO was found to be 20.5 mg/l. In September of 2008 efforts were made to reduce the possible contamination of the groundwater by 'air lifting' the sediment from the bottom of the monitoring well and re-developing the monitoring well for the October sampling event. The sample from October resulted in a DRO level of 18.8 mg/l.	Pam Clemens
2/20/2009	Exposure Tracking Model Ranking	A new updated ranking with ETM has been completed for source area 73719 Drywell and Heating Oil Tanks.	Bill O'Connell
5/19/2009	Cleanup Complete Determination Issued	The Alaska Department of Environmental Conservation, Contaminated Sites Program (ADEC) has completed a review of the environmental records associated with the USGS Government Hill Site located at 132/140 East Manor Avenue in Anchorage, Alaska. Based on the information provided to date, it has been determined that the contaminant concentrations remaining on site do not pose an unacceptable risk to human health or the environment and no further remedial action will be required as long as the site is in compliance with established institutional controls.	Bill O'Connell
5/19/2009	Institutional Control Record Established	Institutional Controls established and entered into the database.	Bill O'Connell
6/29/2009	Document, Report, or Work plan Review - other	Report received detailing the decommissioning of monitoring well MW-3 in accordance with the ROD. Well was overdrilled and filled with bentonite.	Bill O'Connell
10/12/2009	Document, Report, or Work plan Review - other	Reviewed groundwater monitoring report for 2009. Well MW02 was sampled as part of Cleanup Complete ICs. The well was purged dry, then allowed to recharge overnight. DRO was detected at 10.3 mg/l, however it was noted that there was sediment in the water sample, potentially biasing the results high.	Bill O'Connell
4/7/2010	Update or Other Action	USGS is moving forward with a transfer of this property to the Municipality of Anchorage/Anchorage Historical Society for development of a museum and interpretive center.	Bill O'Connell
9/15/2011	Document, Report, or Work plan Review - other	Reviewed 2011 groundwater monitoring report for USGS Government Hill, aka 132/140 East Manor Avenue. One sample and a duplicate were collected from well MW-2. DRO was detected up to 7.68 mg/l. This concentration is lower than, but consistent with previous sample results	Bill O'Connell
9/11/2012	Document, Report, or Work plan Review - other	Reviewed 2012 Groundwater Sampling Report. One sample was collected from MW-2 after the well was purged dry. DRO was detected at 21.2 mg/l.	Bill O'Connell
11/18/2013	Institutional Control Compliance Review	Groundwater contamination in MW-2 has been stable over the last several years of sampling, therfore this requirement is removed and groundwater monitoring will no longer be required at the site.	Bill O'Connell
5/13/2014	Document, Report, or Work plan Review - other	Work plan for well decommissioning approved	Bill O'Connell
6/5/2014	Document, Report, or Work plan Review - other	Monitoring well MW-2 was decommissioned in accordance with ADEC guidance in May 2014.	Bill O'Connell

Action Date

Action

Description

DEC Staff

2/7/1997

Update or Other Action

Phase 1 Environmental Site Assessment 132/140 East Manor Avenue Anchorage, Alaska, dated February 1997 and submitted by Environmental Health Seciences-Alaska and Shannon & Wilson. Potential sources of contamination identified, including two former Quonset hut reportedly used for vehicle maintenance, three USTs and a dry well

Grant Lidren

3/5/1998

Site Added to Database

Phase II assessment received October, 1997 identifying contamination.

Jim Frechione

3/5/1998

Update or Other Action

Interim Action performed at the site.

Jim Frechione

3/27/1998

Update or Other Action

DEC completed review of the October 1997 Follow-up Underground Storage Tank Release Assessment Report. Four soil borings were advanced, soil samples collected and B-4 completed as a groundwater monitoring well. Groundwater contained 1.6 mg/l DRO and 0.32 mg/l methalene chloride. Investigation of a former dry well identified soil contamination DRO-6,000 mg/kg, RRO-26,000 mg/kg, PCB's 5 mg/kg and eleveated metals not attributed to background. Additional work required.

David Pikul

8/4/1998

Meeting or Teleconference Held

Meeting at USGS between USGS, ADEC, Shannon and Wilson to discuss additional site work.

David Pikul

8/4/1998

Update or Other Action

Site visit conducted by ADEC.

David Pikul

9/2/1998

Site Characterization Workplan Approved

Phase III Soil and Groundwater Assessment Workplan review. ADEC approved the workplan subject to the conditions listed in the comment letter.

David Pikul

1/15/1999

Update or Other Action

LC 14693060 established.

David Pikul

1/29/1999

Update or Other Action

DEC completed review of the report: Phase III Soil and Groundwater Assessment of the USGS Facility at 132/140 East Manor Avenue, Anchorage (Government Hill). Three monitoring wells were installed and soil and groundwater collected for laboratory analysis.

David Pikul

7/19/1999

Update or Other Action

ADEC's January comment letter faxed to Bill Fitzpatrick of USGS as he informed ADEC that he did not have the letter.

David Pikul

11/2/1999

Site Ranked Using the AHRM

Not previously ranked.

David Pikul

11/16/1999

Update or Other Action

A letter was issued to USGS stating that a considerable amount of time has passed since a letter was sent to their agency and requested USGS to indicate their intentions regarding the property.

David Pikul

5/16/2000

Meeting or Teleconference Held

Meeting with RP (USGS) to discuss remaining issues and work plan development.

David Pikul

7/27/2000

Update or Other Action

ADEC issued a reminder letter to USGS regarding work plan submittal to address outstanding issues.

David Pikul

8/4/2000

Update or Other Action

ADEC conducted a site visit to inspect the newly installed fence that was to restrict access to the drywell and excavated soils left on the ground surface. The fence is free standing, 8' x 8' chain-link enclosed dog kennel. Its placement did not enclose the soils removed from the dry well that are situated on the ground surface. The RP was notified by e-mail of the site status.

David Pikul

9/18/2000

Meeting or Teleconference Held

ADEC met with RP's consultant (Shannon and Wilson) to discuss site activities to be conducted without an ADEC approved workplan. Driller and excavator scheduling was short notice and did not allow for ADEC review prior to work activities. ADEC verbally concurred with the basics of the workplan and will review ASAP.

David Pikul

9/29/2000

Interim Removal Action Approved

Site visit conducted during drywell excavation, direct haul soil transport and disposal approval given.

David Pikul

10/2/2000

Site Characterization Workplan Approved

ADEC issued comment letter to site characterization work plan submitted, approval given, however, an amendment was requested to investigate pipe from drywell.

David Pikul

10/4/2000

Update or Other Action

Site visit conducted. Use of down-hole camera indicates that the pipe from the drywell may go into the sewer. AWWU verification requested by ADEC.

David Pikul

12/5/2000

Update or Other Action

Cost Recovery Referral Memorandum issued to Department of Law.

David Pikul

1/16/2001

Update or Other Action

Received Additional Investigation and Limited Cleanup report, prepared by Shannon and Wilson.

Scott Pexton

4/3/2001

Site Characterization Report Approved

Letter sent to Bill Fitzpatrick of USGS with approval of report entitled "Additional Investigation and Limited Cleanup" prepared for the USGS by Shannon and Wilson, Inc.

Scott Pexton

4/3/2001

Record of Decision

ADEC signed Record of Decision regarding alternative cleanup levels for soil using Method Three. The default foc and hydraulic gradient parameters were modified by ADEC to calculate these levels. Since the levels are different than those proposed by USGS (and their consultant), they shall be afforded the option to collect additional data from the site to be considered in establishing alternative cleanup levels. As a condition of establishing alternative cleanup levels, ADEC requires the installation of groundwater monitoring wells north of the site within the road right-of-way to evaluate on-site transport of contaminants from adjacent property. In addition, ADEC requests another groundwater sample event from monitoring wells MW-2 and MW-3 with samples analyzed for BTEX and DRO. The MW-2 sample should also be analyzed for methylene chloride. Following the review of the analytical data from these samples, ADEC shall evaluate the need for additional sampling and/or other cleanup actions.

Scott Pexton

4/3/2001

Cleanup Level(s) Approved

ADEC approved Method Three alternative soil cleanup levels as documented in Record of Decision. Cleanup levels approved were 0.03 mg/kg for benzene, 700 mg/kg for DRO, 0.02 mg/kg for methylene chloride, and 0.05 for trichloroethylene.

Scott Pexton

4/12/2001

Site Number Identifier Changed

Site Number Identifier Changed this date.

Former Staff

6/14/2001

Update or Other Action

Received faxed copy of Workplan for Additional Investigation prepared by Shannon and Wilson.

Scott Pexton

6/20/2001

Site Characterization Workplan Approved

Letter sent to Bill Fitzpatrick of USGS with conditional approval of workplan. Conditions include: field work tasks must be completed by August 15, 2001; at least two soil samples collected from each monitoring well soil boring will be submitted for laboratory analysis of DRO, BTEX, and HVOs; and, soil samples will be collected and submitted for DRO/RRO analysis at the same locations as the two soil samples collected for analysis for total organic carbon.

Scott Pexton

8/14/2001

Update or Other Action

ADEC received copy of letter from Department of Law indicating receipt of a check from the U.S. GSA for cost recovery (Bill #CO15427).

Scott Pexton

1/2/2002

Update or Other Action

Received Additional Investigation report prepared by Shannon and Wilson. Two groundwater monitoring wells (MW-4 and MW-5) were installed upgradient of MW-2 and sampled. Analytical results of samples from MW-4 and MW-5 indicated that BTEX, DRO, and RRO were undetected at the method detection limit. One of the conclusions in the report was that "the results of the investigation indicate that an upgradient source of contamination from Monitoring Well MW-2 is unlikely and the possible source remains unknown."

Scott Pexton

2/12/2002

Site Characterization Report Approved

Letter sent to Bill Fitzpatrick of USGS with approval of site characterization report based on information provided in the "Additional Investigation, 132/140 East Manor Avenue" report prepared by Shannon and Wilson, Inc. ADEC concurred with the recommendation to excavate the benzene-impacted soils at the former Tank 3 area for transport to the Alaska Soil Recycling facility in Anchorage for thermal treatment. The action will require ADEC approval of a cleanup plan prepared in accordance with 18 AAC 75.360. Based on the information provided, ADEC concluded that groundwater results have adequately demonstrated that RRO, benzene, toluene, ethylbenzene, total xylenes, methylene chloride, and trichloroethylene did not exceed applicable groundwater cleanup levels. Therefore, ADEC does not require further groundwater sampling for these chemicals in the monitoring wells installed to evaluate groundwater at this site. With respect to DRO in groundwater, sampling results have adequately demonstrated that DRO did not exceed applicable cleanup levels at monitoring wells MW-1, MW-4, and MW-5. Therefore, in accordance with 18 AAC 75.345(h), ADEC will discontinue the requirement for groundwater monitoring at monitoring wells MW-1, MW-4, and MW-5. These monitoring wells may be decommissioned. ADEC concluded that DRO in groundwater did not exceed the applicable cleanup level during October 2001, but did exceed the cleanup level during previous sampling events at monitoring wells MW-2 and MW-3 within Lot 3. Based on the information provided, the concentration trend of DRO in groundwater appears to be stable and decreasing. However, ADEC requested another groundwater sampling event to collect and analyze DRO in groundwater from monitoring wells MW-2 and MW-3. The report suggested that the DRO contamination of 1,500 mg/kg in soil previously sampled at soil boring B-4 be allowed to naturally attenuate. The report suggested that because the soil contamination was located below the water table at 38 feet and was not observed above the water table, that no further action may be appropriate. ADEC may consider this type of request after the cleanup and monitoring actions discussed above are completed, provided an institutional control is established for the property in accordance with 18 AAC 75.375. In accordance with the cleanup operation requirements of 18 AAC 75.360, a cleanup plan was requested by May 1, 2002. The cleanup plan should provide detailed specifications of the proposed soil removal action and groundwater sampling at MW-2 and MW-3. The plan should also include a soil confirmation sampling and analysis plan to confirm that remaining soil after excavation and removal meets applicable cleanup levels. The plan should include a schedule for conducting fieldwork, monitoring, and submittal of a final cleanup report. The site cleanup must be conducted or supervised by a qualified person.

Scott Pexton

4/24/2002

Update or Other Action

ADEC received a letter from the Department of Law indicating that a check was received from USGS for cost recovery (Bill # CO25145).

Scott Pexton

5/10/2002

Update or Other Action

ADEC received Workplan for Limited Cleanup and Groundwater Monitoring, prepared by Shannon & Wilson, Inc. The primary purpose is to excavate and remediate benzene-impacted soil from the former Tank 3 excavation and to collect groundater samples from monitoring wells MW-2 and MW-3.

Scott Pexton

5/20/2002

Cleanup Plan Approved

Letter with plan approval sent to John Spielman of Shannon & Wilson, Inc. (copy to Bill Fitzpatrick of USGS).Benzene-impacted soil will be excavated from former excavation area of Tank #3. Soil will be transported for thermal treatment to the Alaska Soil Recycling facility in Anchorage. Groundwater samples will be collected from monitoring wells MW-2 and MW-3 for DRO lab analysis. Monitoring wells MW-1, MW-4, and MW-5 will be decommissioned. Approval letter had a request to submit the final cleanup report to ADEC by July 15, 2002.

Scott Pexton

8/1/2002

Update or Other Action

Limited Cleanup and Groundwater Monitoring report with this date submitted by Shannon & Wilson

Grant Lidren

8/14/2002

Meeting or Teleconference Held

Meeting with USGS rep Bill Fitzpatrick and Shannon&Wilson consultant, John Spielman. Was given a copy of the latest report to review.

Lynne Bush

8/15/2002

Meeting or Teleconference Held

Site visit.

Lynne Bush

10/8/2002

Update or Other Action

Telephone conversation w Fitpatrick about long-term monitoring and IC issues.

Lynne Bush

10/9/2002

Update or Other Action

Follow-up on IC issues - sent copy of draft guidance to Mr. Fitzpatrick.

Lynne Bush

5/5/2003

Update or Other Action

Letter to Fitzpatrick asking for information

Lynne Bush

5/6/2003

Update or Other Action

Fitzpatrick will be sending in a long-term monitoring work plan and information to be used to complete a ROD/NEC for this site.

Lynne Bush

1/29/2004

Update or Other Action

File number changed from CS80.01 to 2100.38.325

Former Staff

8/16/2004

Update or Other Action

File tranferred to Juneau office

Sarah Cunningham

2/13/2007

Update or Other Action

Corrected 3/27/1998 and 1/29/99 entries to reflect administrative file.

Shannon Oelkers

6/24/2007

Update or Other Action

File sent to Anchorage, PM changed to O'Connell.

Bill O'Connell

6/25/2007

Site Characterization Workplan Approved

Approved work plan to sample MW-2.

Bill O'Connell

7/23/2007

Site Characterization Report Approved

Received 2007 groundwater monitoring report. One sample was collected from monitoring well MW2 which contained DRO at 2.15 mg/l.

Bill O'Connell

8/30/2007

Exposure Tracking Model Ranking

Bill O'Connell

10/9/2007

Site Characterization Workplan Approved

Reviewed work plan for groundwater monitoring at MW-2. Samples will be collected infall 2007 and spring 2008 and analyzed for DRO.

Bill O'Connell

2/7/2008

Site Characterization Report Approved

Groundwater sampling report dated December 17, 2007 submitted by Shannon & Wilson and recieved by the ADEC on this date. One sample was collected, on October 24, 2007, from monitoring well MW2 which contained DRO at 0.940 mg/L

Grant Lidren

2/8/2008

GIS Position Updated

Updated using Arc GIS SPAR_StatewideLocator (ArcReader)

Grant Lidren

1/6/2009

Document, Report, or Work plan Review - other

Received January 5, 2009 from Shannon & Wilson the Groundwater Sampling, 132/140 East Manor Avenue report that was completed November 2008. Monitoring well #2 was sampled July 18, 2008 and October 3, 2008. In July DRO was found to be 20.5 mg/l. In September of 2008 efforts were made to reduce the possible contamination of the groundwater by 'air lifting' the sediment from the bottom of the monitoring well and re-developing the monitoring well for the October sampling event. The sample from October resulted in a DRO level of 18.8 mg/l.

Pam Clemens

2/20/2009

Exposure Tracking Model Ranking

A new updated ranking with ETM has been completed for source area 73719 Drywell and Heating Oil Tanks.

Bill O'Connell

5/19/2009

Cleanup Complete Determination Issued

The Alaska Department of Environmental Conservation, Contaminated Sites Program (ADEC) has completed a review of the environmental records associated with the USGS Government Hill Site located at 132/140 East Manor Avenue in Anchorage, Alaska. Based on the information provided to date, it has been determined that the contaminant concentrations remaining on site do not pose an unacceptable risk to human health or the environment and no further remedial action will be required as long as the site is in compliance with established institutional controls.

Bill O'Connell

5/19/2009

Institutional Control Record Established

Institutional Controls established and entered into the database.

Bill O'Connell

6/29/2009

Document, Report, or Work plan Review - other

Report received detailing the decommissioning of monitoring well MW-3 in accordance with the ROD. Well was overdrilled and filled with bentonite.

Bill O'Connell

10/12/2009

Document, Report, or Work plan Review - other

Reviewed groundwater monitoring report for 2009. Well MW02 was sampled as part of Cleanup Complete ICs. The well was purged dry, then allowed to recharge overnight. DRO was detected at 10.3 mg/l, however it was noted that there was sediment in the water sample, potentially biasing the results high.

Bill O'Connell

4/7/2010

Update or Other Action

USGS is moving forward with a transfer of this property to the Municipality of Anchorage/Anchorage Historical Society for development of a museum and interpretive center.

Bill O'Connell

9/15/2011

Document, Report, or Work plan Review - other

Reviewed 2011 groundwater monitoring report for USGS Government Hill, aka 132/140 East Manor Avenue. One sample and a duplicate were collected from well MW-2. DRO was detected up to 7.68 mg/l. This concentration is lower than, but consistent with previous sample results

Bill O'Connell

9/11/2012

Document, Report, or Work plan Review - other

Reviewed 2012 Groundwater Sampling Report. One sample was collected from MW-2 after the well was purged dry. DRO was detected at 21.2 mg/l.

Bill O'Connell

11/18/2013

Institutional Control Compliance Review

Groundwater contamination in MW-2 has been stable over the last several years of sampling, therfore this requirement is removed and groundwater monitoring will no longer be required at the site.

Bill O'Connell

5/13/2014

Document, Report, or Work plan Review - other

Work plan for well decommissioning approved

Bill O'Connell

6/5/2014

Document, Report, or Work plan Review - other

Monitoring well MW-2 was decommissioned in accordance with ADEC guidance in May 2014.

Bill O'Connell

Contaminant Information

Name	Level Description	Media	Comments
DRO	Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation	Soil

Name

Level Description

Media

Comments

DRO

Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation

Soil

Control Type

Type	Details
Signed CS Determination

Type

Details

Signed CS Determination

Requirements

Description	Details
Advance approval required to transport soil or groundwater off-site.

Description

Details

Advance approval required to transport soil or groundwater off-site.

Record of Decision

No associated sites were found.

Missing Location Data

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Site Report: USGS Government Hill Site

Site Chronology

IC / Closure Details

Documents

Associated Sites

Problems/Comments

Action Information

Contaminant Information

Control Type

Requirements

Record of Decision

Missing Location Data

State of Alaska Department of Environmental Conservation