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Site Report: Gerstle River Test Site-UST #450 and #451

Site Name: Gerstle River Test Site-UST #450 and #451
Address: BLDG.450 & 451, Delta Junction, AK 99737
File Number: 141.26.008
Hazard ID: 24980
Status: Cleanup Complete - Institutional Controls
Staff: Erica Blake, 9074512182 erica.blake@alaska.gov
Latitude: 63.792949
Longitude: -145.035626
Horizontal Datum:NAD83

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.

Problems/Comments

A September 1994 report “Underground Storage Tank Removal, Site Assessment, and recommendations” that documents the removal of two 500-gallon USTS one contained gasoline the other Diesel. Approximately 300 yds3 of contaminated soil were excavated during the removal, identified as contaminated and returned to the hole. The report concludes “Based on the findings of the site investigation and assessment, it is recommended that this site remain a LUST site at this time. Any further remediation plan should consider all sources of subsurface pollution affecting this site.” We have no further correspondence regarding this site.

Action Information

Action Date Action Description DEC Staff
6/12/1992 Site Added to Database Former Staff
6/12/1992 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 78097 Former Staff
10/21/1994 Leaking Underground Storage Tank Cleanup Initiated - Petroleum entered by JC Former Staff
10/21/1994 Underground Storage Tank Site Characterization or Assessment Tank removal/Preliminary Site Assessment report received. Highest DRO 6.1 although 745 ppm in data but not mentioned in report (presumably from 300 yd stockpile which was subsequently returned to excavation). SA 7/14/94. CN 7/45/94. No Post-C. No FacID. Former Staff
8/21/2002 Update or Other Action RECKEY has automatically been generated. Cynthia Pring-Ham
1/28/2004 Update or Other Action Transferred DEC staff lead from John Carnahan Cynthia Pring-Ham
6/26/2008 Exposure Tracking Model Ranking Intitial Ranking Complete for Source Area: 78097 (Autogenerated Action)
10/14/2009 Document, Report, or Work plan Review - other Provided comments to the USAGAK on the Draft "Abandoned UST Investigation in the Administrative Area" work plan. The work plan details the proposed investigation strategy for characterizing the extent and magnitude of petroleum contamination remaining in the vicinity of the former UST. COmment focused on inconsistencies within the planning documents and appropriate borehole decommissioning and sampling procedures. Work is scheduled to begin upon approval of the project planning documents. Guy Warren
10/14/2009 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 78097 name: UST Guy Warren
4/12/2010 Document, Report, or Work plan Review - other Received Draft Investigation Report for Tank #000 and #450 and #451 on 3/30/2010. Provided comments to the Army on this date. ADEC was unable to concur with the conclusions of the report for several reasons primarily that the maximum vertical extent of contamination had not been reached and therefore the sites were not adequately characterized. The Army has agreed to perform additional characterization at these sites during the 2010 Field season. Guy Warren
9/16/2010 Document, Report, or Work plan Review - other Received 2010 Work Plan addendum for additional characterization at the GRTS Administrative area. Work plan addressed agreed to sampling and investigation to complete characterization of this site. In addition a third LUST site #449 was included in the investigation at the request of ADEC. This work should address ADEC site characterization requirements for all three remaining LUST sites at the GREA. Submitted work plan approval letter with minimal comments. Guy Warren
7/21/2011 Document, Report, or Work plan Review - other Received final assessment report “Investigation of Abandoned Underground Storage Tank Sites in the Administrative Area” for the Gerstle River Test Site, AK. The report identifies the extent of petroleum contamination at three UST sites (#000, #450/451, and #499). At former UST #450/451 DRO, GRO and VOC soil contamination, above migration to groundwater cleanup levels, extend from 10 to approximately 20 ft below ground surface. Groundwater at this site is over 400 ft BGS and exposure to contamination is likely only during excavation activities that extend beneath 10 ft. The report recommends site closure with institutional controls to prevent unintended excavation of contaminated media. A decision document will be prepared to document the decision and identify appropriate IC’s for implementation. Guy Warren
5/15/2014 Update or Other Action Submit Closure Determination to US Army for GRTS Administrative Areas UST site #450/451. The UST was removed from the site in the mid 1990’s. Site assessment work during the tank removals and subsequent release investigation work have documented some residual petroleum in soil at this site. Because groundwater is located over 400 feet below the ground surface, migration of contaminants from soil to the groundwater is not a pathway of concern. Therefore, the approved cleanup levels for GRTS UST sites are the most stringent of the soil direct contact, ingestion or inhalation cleanup levels established in 18 AAC 75.341 (d), Table B1 and B2. Surface soil at the site meets the approved cleanup levels, however, contaminated soil remains between depths of 11 and 15 feet below ground surface. ADEC has determined the residual contamination does not pose an unacceptable risk as long as it remains in place and is not relocated to an area where exposure could occur. Therefore, ADEC is requesting the Army establish ICs restricting future excavation at the site to ensure contaminated soil is not exposed or moved to a location where it could pose potential risk. Once the IC’s have been established we will update site status on the database. Guy Warren
9/4/2014 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 78097 UST. Guy Warren
5/22/2015 Document, Report, or Work plan Review - other Submit comments to US Army on the Draft LTM plan for the GRTS. The plan identified LUC's required for UST #450 and Best Management Practices for the remainder of the property. Guy Warren
7/23/2015 Document, Report, or Work plan Review - other Submit approval letter for Final Long Term Management Plan for the Gerstle River Test Site. The document outlines the required institutional controls for interim management of the lingering CWM issues as well as to address petroleum contamination remaining at the former USTs. Guy Warren
4/29/2016 Cleanup Complete Determination Issued Submit letter to US Army notifying them of the site status change for UST #450 and #451. ADEC received the Final “Long-Term Management Plan, Gerstle River Test Site (GRTS), AK” on July 20, 2015. This plan establishes Land Use Controls (LUC’s) for the GRTS and UST #450 and #451. In accordance with ADEC’s May 14, 2014 closure determination, the establishment of LUCs for UST #450 and #451 was required prior to changing the site status in ADEC’s Contaminated Sites (CS) Database. Guy Warren
4/29/2016 Institutional Control Record Established Institutional Controls established and entered into the database. Guy Warren
10/4/2023 Institutional Control Compliance Review DEC provided review comments for the "Draft 2022 Land Use Controls Inspection Report, Gerstle River Test Site, U.S. Army Garrison Alaska, dated August 2023" to the U.S. Army. The document describes an assessment of the institutional controls and discusses the results of a site inspection completed in 2022. Erica Blake
1/2/2024 Document, Report, or Work plan Review - other DEC provided responses to comments for the "Draft 2022 Land Use Controls Inspection Report, Gerstle River Test Site, U.S. Army Garrison Alaska" (dated August 2023) to the U.S. Army. The document describes land use control and institutional control inspections conducted in 2022. All responses to comments have been accepted pending a comment backcheck of the final document. Erica Blake

Contaminant Information

Name Level Description Media Comments
DRO Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.
GRO Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.
Benzene Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.
Xylenes (total) Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.
1,2-Dibromoethane Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.
1,2,4-Trimethylbenzene Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Contaminated soil present between 11 and 15 feet BGS.

Control Type

Type Details
Federal or State Agency GIS Database Note
Institutional Control Management Plan

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.
Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70)
Periodic Review Annual LUC inspection and reporting.

No associated sites were found.

Missing Location Data

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