Site Report: Dutch Hbr-Unalaska Vly UST 3065
| Site Name: | Dutch Hbr-Unalaska Vly UST 3065 |
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| Address: | South of Building UV2965, Upper Broadway, Unalaska, AK 99685 |
| File Number: | 2542.38.023 |
| Hazard ID: | 2887 |
| Status: | Active |
| Staff: | Kathleen Iler-Galau, 9074512153 kathleen.iler-galau@alaska.gov |
| Latitude: | 53.844493 |
| Longitude: | -166.503567 |
| Horizontal Datum: | WGS84 |
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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
Building 3065 was a former latrine located next to a small creek south of Building UV-2965. In 1997, a 500 square foot area was excavated to bedrock and the 300 gallon heating oil UST was removed, along with 47 cubic yards of impacted soil. Confirmation sampling indicated DRO remaining up to 19,000 mg/kg. In 2000, a 19 foot by 42 foot area was excavated in the vicinity of the previously detected contamination. The excavation was limited by the creek to the south and the building foundation to the south and west. Approximately 55 cubic yards of contaminated soil was removed to a depth of 4 feet below ground surface, where groundwater was encountered. Groundwater was below Table C, however DRO remained in soil sampled at concentrations of 1,100 and 910 mg/kg at 3 and 5 feet bgs southeast of the excavation area. Update 11/2021 - Site is being prioritized under the Amaknak Restoration Advisory Board, along with six other UST sites in the Unalaska Valley. Site is a candidate for potential removal action, concrete foundation was removed as part of debris cleanup.
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 6/5/2000 | Site Characterization Report Approved | Comprehensive Remedial Investigation Report, dated May 2000 and prepared by Jacobs Engineering, documents this ~300 gallon UST was removed in 1997; approximately 50 cy of petroleum contaminated soil were removed and thermally treated. The site is adjacent to wetlands and a creek. Concerns over impacts to the surface waters and bedrock being present at 4-5 feet below ground limited further removal . Four soil samples were collected from 1-2.5' bgs. BTEX, PAHs and RRO did not exceed the most stringent method 2 soil cleanup levels. DRO exceeded the cleanup level in one sample at, where it was found at 19,000 mg/kg. The report recommends evaluation of further removal in a manner that would not cause water quality problems in the wetland and creek along with working with the landowner to establish institutional controls. Two test pits were installed to help delineate the apparent extent of impacts and did not indicate contamination at either location. Bedrock and groundwater limited further excavation. Ten soil samples were collected at the limits of the excavation and analyzed for DRO, RRO, PAHs, and BTEX. All analytical results met the most stringent method 2 soil cleanup levels with the exception of DRO. Two of the ten samples contained DRO at 5,200 and 7,000 mg/kg, exceeding the migration to groundwater cleanup levels but not the ingestion or inhalation levels. Residual soil contamination appears to be isolated in extent; due to shallow bedrock and a surface water reservoir that supplies most of the City water, it is unlikely that drinking water wells would be installed in the future. | John Halverson |
| 1/23/2003 | Site Added to Database | Unalaska Valley expanded into a total of 26 unique sites from one. | John Halverson |
| 6/13/2003 | CERCLA SI | The 2001/2002 Islandwide SI/RI/IRA Report was received. The report documents the work completed during the 2001 and 2002 field seasons at various sites throughout Amaknak and Unalaska. In 2001 a hand auger was advanced in two locations to determine if soil contamination was migrating from the site. In 2002 sediment, surface and ground water samples were collected. Groundwater was non-detect for DRO and surface water was below cleanup levels. DRO was detected in the creek sediment, and the soil sample had concentrations of DRO above cleanup levels at 1,100 mg/kg. THe report recommends no further action for the site as excavation would not be feasible becuase of the proximity to the creek and high groundwater levels. The report recommends institutional controls be determined through coordination between the agencies and property owner. | Meghan Dooley |
| 12/8/2003 | GIS Position Updated | TopoZone | Debra Caillouet |
| 6/10/2005 | Update or Other Action | File number issued 2542.38.023. | Aggie Blandford |
| 7/3/2008 | Exposure Tracking Model Ranking | Initial ranking with ETM completed. | Daniel Fremgen |
| 9/14/2010 | CERCLA Proposed Plan | ADEC received the draft final Proposed Plan #7 addressing Unalaska Valley Management Area 11. The plan recommends Alternative 2 (Corrective Action Complete/Cleanup Complete with ICs) for UST 3065. Remaining DRO contamination is localized. Contamination remains near or under the building foundation but does not appear to be migrating to groundwater, surface water, or nearby sediment. The source has been removed to the extent practicable, and shallow groundwater makes excavation logistically difficult. | Meghan Dooley |
| 9/13/2019 | Update or Other Action | Site location was updated on this date. Coordinates for this site are used to determine the presence and position of the site on BLM’s ANCSA Conveyed Land web map. | Rebekah Reams |
| 11/10/2021 | Update or Other Action | Site is being prioritized under the Amaknak Restoration Advisory Board, along with six other UST sites in the Unalaska Valley. Site is a candidate for potential removal action, concrete foundation removed as part of debris cleanup. Historical contamination DRO 33,200 mg/kg at 3 ft bgs and DRO 22,800 mg/kg at 4 ft bgs. | Cascade Galasso-Irish |
| 4/24/2023 | Document, Report, or Work plan Review - other | Bulk action entry for Unalaska Valley UST sites: on this date, DEC received and approved the Final Work Plan - CON/HTRW Limited Removal Action Unalaska Valley Amaknak FUDS - F10AK0841-13, Unalaska, Alaska Dated April 7, 2023. The fieldwork will consist of a combination of drilling, excavation, soil sampling, groundwater sampling, and surface water sampling, in addition to an optional task of drafting environmental covenants for select properties. | Cascade Galasso-Irish |
| 7/17/2023 | Document, Report, or Work plan Review - other | DEC received a work plan addendum for the Amaknak FUDS Unalaska Valley work plan, regarding two requested deviations to the work plan. These deviations were for USTs 3065 and 3260, and included: 1. the incorporation of silica gel cleanup methods to limit biogenic interference in the laboratory analytical results 2. the use of an excavator to install monitoring wells within the source areas during excavation/backfill activities. DEC reviewed and approved the work plan addendum on July 17, 2023. | Cascade Galasso-Irish |
| 1/25/2024 | Document, Report, or Work plan Review - other | Bulk action entry for review of the Draft Restoration Summary Report Containerized Hazardous, Toxic, and Radioactive Waste, Amaknak Formerly Used Defense Sites, recommending closure at 53 sites. DEC received the draft summary report on April 2023, and provided comments on June 2023. On January 15, 2024, FUDS submitted a final summary report. Comment resolution has not been performed and is not complete. Further coordination is necessary with FUDS. | Cascade Galasso-Irish |
Contaminant Information
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Control Type
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Requirements
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No associated sites were found.