Site Report: Dutch Hbr-Unalaska Vly UST 3675
| Site Name: | Dutch Hbr-Unalaska Vly UST 3675 |
|---|---|
| Address: | Overland Drive, UST 3675, Unalaska, AK 99685 |
| File Number: | 2542.38.023 |
| Hazard ID: | 2895 |
| Status: | Cleanup Complete |
| Staff: | No Longer Assigned, 9074655229 dec.icunit@alaska.gov |
| Latitude: | 53.851627 |
| Longitude: | -166.494679 |
| 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
A heavily corroded 300 gallon heating oil UST-3675 was removed along with 58 cubic yards of impacted soil in 1997 at the former latrine building in Unalaska Valley. Little evidence of the former building remains and the tank was covered with approximately one foot of soil. Eighty-five gallons of water was removed from the UST and field screening indicated POL-impacted soil in the excavation. Exploratory test pits revealed a limited horizontal extent of contamination. Removal of the tank and POL-impacted soil resulted in a 290 square foot excavation. Confirmation sampling indicated one DRO exceedance at 1500 mg/kg. The recommendation by FUDS was that additional excavation would not be practical due to bedrock boundary conditions encountered in 1997. Site details are present in the 1997 IRA/SI/RI Report, the 2000 Comprehensive Remedial Investigation Report, and Proposed Plan #7.
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 6/5/2000 | Site Characterization Report Approved | DEC received the May 2000 Comprehensive Remedial Investigation Report, prepared by Jacobs Engineering. The report documents removal of this ~300 gal heating oil tank and ~60 cy of petroleum contaminated soil, which was thermally treated on island. Three confirmation soil samples were collected and analyzed for DRO, RRO and BTEX. DRO exceeded the method two migration to groundwater cleanup level in one of three samples, the maximum concentration being 1,500 mg/kg at the bedrock interface ~8' bgs. The report recommneds no further action because of the apparent limited volume of residual contamination and the fact it is at the soil/bedrock interface. | John Halverson |
| 1/23/2003 | Site Added to Database | Unalaska Valley expanded into a total of 26 unique sites from one. | John Halverson |
| 12/9/2003 | GIS Position Updated | TopoZone | Debra Caillouet |
| 6/10/2005 | Update or Other Action | File number issued 2542.38.023. | Aggie Blandford |
| 7/10/2008 | 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 1 (Corrective Action Complete/Cleanup Complete with NDAI) for UST 3675. Remaining contamination is localized in bedrock fractures, the source has been removed to the extent practicable, and remaining contamination is less than the calculated Method 3 ACLs. | Meghan Dooley |
| 4/27/2021 | Update or Other Action | Coordinates on CSP application updated. Changed coordinates on CSP application from: 53.852500 -166.492778 to 53.851627 -166.494679 and datum was added, site location was verified using satellite imagery and figures in both Amakanak Proposed Plan #7.pdf and 2888_Amakanak 2001-2002 SI-IR-IRA Report.pdf | Ginna Quesada |
| 10/9/2023 | Exposure Tracking Model Ranking | A new updated ranking with ETM has been completed for source area 73871 UST. | Cascade Galasso-Irish |
| 11/3/2023 | Cleanup Complete Determination Issued | On this date, a Cleanup Complete Determination was issued for the site. 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 unless information becomes available that indicates residual contaminants may pose an unacceptable risk. | 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 |
| 2/22/2024 | Document, Report, or Work plan Review - other | On this date, DEC reviewed and approved the redline final, RTCs, and final Restoration Summary Report for the Amaknak Formerly Used Defense Sites F10AK0841-13, -14, -15, -16, -18, -20, Unalaska Valley, Pyramid Valley-Port Levashef, Summer Bay-Humpy Cove, Margaret Bay-Airport, Mount Ballyhoo, and Little South America in Unalaska, Alaska. Of the 53 sites included in this report, 39 of these sites are either closed in the Contaminated Sites database or are not eligible active sites. Fourteen (14) sites remain open in the CS database, either pending further coordination on the pathway to closure or are currently with DEC management for closure decision. This letter is documenting the approval of the final document but does not preclude the need for further investigation of sites included in the report. | Cascade Galasso-Irish |
Contaminant Information
| Name | Level Description | Media | Comments |
|---|---|---|---|
| DRO | Other | Soil | DRO soil contamination remains at the site at a maximum concentration of 1,500 mg/kg, below the most stringent calculated ACL for ingestion of 8,300 mg/kg, based on a site-specific foc value of 0.045 g/g. |
Control Type
| Type | Details |
|---|---|
| No ICs Required |
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) |
No associated sites were found.