Site Report: Alyeska PS 09 Therminol Release
| Site Name: | Alyeska PS 09 Therminol Release |
|---|---|
| Address: | Mile 258 Richardson Hwy., Pump Station 9, Delta Junction, AK 99737 |
| File Number: | 330.38.083 |
| Hazard ID: | 3113 |
| Status: | Cleanup Complete - Institutional Controls |
| Staff: | IC Unit, 9074655229 dec.icunit@alaska.gov |
| Latitude: | 63.929978 |
| Longitude: | -145.766497 |
| 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
During scheduled maintenance in July 1998 to inspect and repair "boot liners," which form a seal between the underground liner and concrete footings that support aboveground piping, Alyeska personnel discovered Therminol impacted soil within the tank farm near Tanks 197 and 198 (both of which store therminol). An estimated 200 gallons of therminol were released at Tank 197 and less than 55 gallons at Tank 198. A municipal well (no longer Class C system) exists within 500 feet. 1st aquifer is approximately 110' BGS. Drinking water comes from an aquifer that is first encountered at approximately 390' BGS. Tanks 190, 197, and 198 are all within a secondary containment structure with a total capacity of 104,500 barrels (approx 4,389,000 gallons).
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 2/25/1999 | Update or Other Action | Date of final report by Emcon entitled "Pump Station 9 Tank Farm Therminol Release Soil Sampling". One excavation at Tank 197 and another at Tank 198. Confirmation samples collected at Tank 197 for DRO up to 4,650 mg/kg below liner estimated to be in a limited area but vertical extent below could not be determined because liner had already been repaired. Confirmation samples also collected along the sidewall of the excavation were up to 11,000 mg/kg DRO at Tank 197 perimeter. Samples collected along the sidewall near Tank 198 were up to 14,000 mg/kg DRO. Contaminated soil extending underneath each tank could not be determined without jeapordizing tank integrity. | Keather McLoone |
| 8/29/2000 | Site Added to Database | Therminol contamination. | Bruce Wanstall |
| 1/29/2008 | Exposure Tracking Model Ranking | Initial ranking with ETM completed. | Pam Clemens |
| 2/1/2008 | GIS Position Updated | Updated using Arc GIS SPAR_StatewideLocator (ArcReader) | Grant Lidren |
| 11/7/2011 | Exposure Tracking Model Ranking | A new updated ranking with ETM has been completed for source area 74088 AST 197 & 198. | Keather McLoone |
| 12/26/2012 | Exposure Tracking Model Ranking | Groundwater ingestion pathway has been reassessed (reduced) due to low volume of contaminant that was released, depth to 1st aquifer (~110' BGS), and depth/location of drinking water intake (~300' BGS), which is ~500' away. | Richard Bernhardt |
| 1/7/2013 | Update or Other Action | Updated coordinates based on Google Earth imagery. | Richard Bernhardt |
| 5/24/2013 | Site Characterization Workplan Approved | Received and approved a work plan to collect soil confirmation samples north of Tank 198. Previously contaminated soil northwest of Tank 197 was completely excavated to the liner and removed for offsite remediation in 2012, but additional sampling in this area (in support of a possible closure decision) was pre-approved at the discression of the RP/Consultant. | Richard Bernhardt |
| 1/2/2014 | Update or Other Action | On this date, ADEC received the 2013 Soil Sampling Report for PS 9 Tank 198 submitted by SLR dated December 2013. Two testpits were advanced at tank 198 to a depth of 2 feet bgs adjacent to the 1998 soil sample that contained 14,000 mg/kg DRO. Three soil samples collected from the two testpits contained DRO up to 2,570 mg/kg. | Grant Lidren |
| 4/9/2014 | Cleanup Complete Determination Issued | The Alaska Department of Environmental Conservation (ADEC), Contaminated Sites Program, has completed a review of the environmental records associated with the Alyeska PS 09 Therminol Release. Based on the information provided to date and the administrative record, the ADEC has determined that the contaminant concentrations remaining on site do not pose an unacceptable risk to human health or the environment. No further remedial action will be required as long as the site is in compliance with established institutional controls | Grant Lidren |
| 4/9/2014 | Institutional Control Record Established | Institutional Controls established and entered into the database. | Grant Lidren |
| 5/9/2014 | Update or Other Action | On this date, ADEC received the signed CC-IC agreement from Alyeska. | Grant Lidren |
| 11/23/2015 | Institutional Control Compliance Review | IC compliance review conducted, staff changed from Lidren to IC unit, and reminder system set to review the site record in April 2019. | Nathan Maxwell |
| 6/18/2018 | Institutional Control Compliance Review | IC compliance review conducted. Closure/IC Details updated. | Kristin Thompson |
| 3/11/2019 | Institutional Control Compliance Review | ICs verification letter from Alyeska received this date. The letter documents compliance with all IC requirements. The next IC review will be in five years time. | Evonne Reese |
| 9/25/2024 | Institutional Control Compliance Review | The landowner responded to the IC reminder letter and provided a written confirmation that land use has not changed | Gaige Robinson |
Contaminant Information
| Name | Level Description | Media | Comments |
|---|---|---|---|
| DRO | > Human Health/Ingestion/Inhalation | Soil |
Control Type
| Type | Details |
|---|---|
| Signed CS Determination |
Requirements
| Description | Details |
|---|---|
| Advance approval required to transport soil or groundwater off-site. | Standard condition. |
| When Contaminated Soil is Accessible, Remediation Should Occur | The soil contamination located under Tank 197 and at Tank 198 is currently inaccessible. When the tanks and liner are removed and/or the soil becomes accessible, the soil must be evaluated to the satisfaction of ADEC. |
| Other | Alyeska will report to ADEC every five years to document land use, or report as soon as they become aware of any changes in land ownership and/or use. |
| Groundwater Use Restrictions | Installation of groundwater wells at this site will require approval from ADEC. |
| Excavation / Soil Movement Restrictions | In the future, if soil is removed from this site it must be characterized and managed following regulations applicable at that time. |
| 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) | Standard condition. |
No associated sites were found.