| Action Date |
Action |
Description |
DEC Staff |
| 6/23/2014 |
Site Characterization Workplan Approved |
The Alaska Department of Environmental Conservation (ADEC) Contaminated Sites Program (CSP) has received and reviewed the 2014 Work Plan RGV-35A submitted by SLR and dated May 2014. ADEC has no objections to the Work Plan and Alyeska may proceed with the following conditions: 1. The groundwater must be analyzed for GRO and BTEX; 2. This site appears to be below the 68o North latitude which is defined as the Arctic Zone in 18 AAC 75.990. Therefore it is assumed this site is in the Under 40 Inch Zone. However, if SLR believes this site is located within the arctic zone, ADEC will require additional site specific data for our records.
|
Grant Lidren |
| 6/27/2014 |
Spill Transferred from Prevention Preparedness and Response Program |
Spill transferred by PERP staff John Ebel. Spill no. 13399916302; spill date = 6/12/13; substance = crude oil; quantity = unknown; PERP file no. 330.02.053. |
Mitzi Read |
| 7/7/2014 |
Site Added to Database |
A new site has been added to the database |
Mitzi Read |
| 7/7/2014 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79643 name: Crude Oil - Remote Gate Valve 35A |
Mitzi Read |
| 7/10/2014 |
Potentially Responsible Party/State Interest Letter |
PRP letter sent to Alyeska on this date. |
Grant Lidren |
| 1/9/2015 |
Site Characterization Report Approved |
On this date, ADEC received the 2014 Groundwater Monitoring Report Remote Gate Valve 35A submitted by SLR dated December 2014. MW-3 sampled on 7/25/14 for DRO and RRO contained detectable levels of DRO and RRO, but below ADEC Table C groundwater cleanup levels. MW-3 sampled again on 8/25/14, for GRO, DRO, RRO, and BTEX did not contain detectable levels of contaminants. |
Grant Lidren |
| 3/3/2015 |
Cleanup Complete Determination Issued |
The Alaska Department of Environmental Conservation (ADEC), Contaminated Sites Program, has completed a review of the environmental records associated with this site. 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 |
| 7/8/2015 |
Update or Other Action |
On this date; MW-1, MW-2, and MW-3 were decommissioned. SLR pulled the 1/4-inch outer diameter tubing connected to the stainless sampling points and filled the holes to the maximum extent possible with powdered bentonite. |
Grant Lidren |
| 2/25/2019 |
Site Characterization Report Approved |
On this date, ADEC received the RGV-35A Sheen Investigation Report_Rev1 submitted by SLR and dated February 25, 2019. Heavy sheen was observed during a routine integrity investigation dig at RGV-35A in 2018 within the 10 foot in diameter historic CMP surrounding the valve. Historic trapped crude oil was observed around the valve housing and below the static water table. Crude oil saturated soils were encountered at 6 to 8 feet bgs in the SE quadrant of the newly installed 17 foot in diameter CMP. Contaminated soil was removed at this location as well as outside the newly installed 17 foot CMP to the best extent practicable to a depth of 8 feet bgs at the top of the pipe. No leaks or structural damage were identified on the valve body, bybass valve piping risers, and top of pipe, including all components on the southeast side of the valve where free crude was observed. Ten confirmation soil samples were collected from the sidewalls and floor of the excavation. Only one soil sample collected from the SE quadrant crude oil stained sidewall at 6 to 7 feet bgs contained contaminants above cleanup levels with DRO at 1,620 mg/kg, 1,2,4-trimethylbenzene at 1.62 mg/kg, 1,3,5-trimethylbenze at 0.825 mg/kg, benzene at 0.856 mg/kg, ethylbenzene at 1.59 mg/kg, naphthalene up to 1.55 mg/kg, and xylenes at 1.81mg/kg. Approximately 10 to 20 cys of contaminated soil was removed and transported to OIT for thermal remediation. A total of 11 MWs and wellpoints were installed to determine the extent of shallow groundwater contamination. None of the groundwater samples were above Table C cleanup levels. Groundwater was encountered from 1.62 to 4.44 feet bgs. |
Grant Lidren |
| 7/16/2019 |
Site Characterization Workplan Approved |
On this date, ADEC received the RGV-35A Well Installation work plan submitted by SLR and dated July 15, 2019. Three borings will be advanced to a depth of 15 feet bgs and completed as monitoring wells. Two soil samples will be collected per boring, one at the groundwater interface and one from the highest pid reading/evidence of contamination. The groundwater will be sampled and groundwater direction will be evaluated. |
Grant Lidren |
| 12/19/2019 |
Site Characterization Report Approved |
On this date, ADEC received the RGV-35A Well Installation report submitted by SLR dated November 22, 2019. Three soil borings were advanced 11.6 to 13.5 feet bgs and completed as monitoring wells (MWs). The MWs were installed 50 feet north, east, and west of the RGV-35A. Five soil samples collected 1.0 to 5.0 feet bgs did not contain contaminant concentrations above Method Two MTG cleanup levels. The monitoring wells were screened 6.63 to 13.45 feet bgs. Groundwater was encountered from the top of the casing during sampling from 2 to 4 feet bgs. Five groundwater samples collected did not contain contaminant concentrations above Table C cleanup levels. Groundwater flow was to the southwest towards the Dietrich River. |
Grant Lidren |
| 6/10/2020 |
Site Characterization Workplan Approved |
On this date, ADEC received the RGV-35A Groundwater Sampling Work Plan submitted by SLR and dated June 10, 2020. Groundwater will be sampled from the three monitoring wells and groundwater direction will be evaluated. |
Grant Lidren |
| 6/10/2021 |
Document, Report, or Work plan Review - other |
The 2020 groundwater monitoring report described the groundwater from the wells installed in 2019 results included estimated concentrations of diesel range organics (DRO) and residual range organics (RRO) between the lab's method detection limit (MDL) and the limit of detection (LOD). Groundwater gradients indicated south-southeasterly flow direction, a change from the southwesterly gradient measured in 2019. Some of the wells have begun to frost-jack. The 2021 work plan describes the intention to sample wells MW-191, MW-192, and MW-193 after trimming the wells casings and re-surveying the top-of-casing elevations. |
Laura Jacobs |
| 4/7/2022 |
Document, Report, or Work plan Review - other |
A review of the RFG-35A Groundwater Monitoring Report summarized three years of groundwater monitoring that continued to result in contaminants of concern being either non-detect or well below the groundwater cleanup level. It is assumed that remaining contaminants from historical leaks are limited to the immediate vicinity of the valve as was documented in 2018. Approval was given to decommission monitoring wells. |
Laura Jacobs |
| 6/6/2022 |
Update or Other Action |
A release of crude oil has been reported at the RGV-35A site after it was observed that a 1/2" valve had a cracked threaded fitting that caused a leak. The observed 6" of product in the 25 foot corrugated metal pipe has been removed by vacuum truck. Coordination has begun to determine the extent of remaining crude oil. |
Laura Jacobs |
| 6/6/2022 |
Site Reopened |
|
Evonne Reese |
| 6/22/2022 |
Spill Transferred from Prevention Preparedness and Response Program |
Alyeska Mile Post 193.962 Crude Oil Gal55; Spill #: 22399915401; File #: 165.02.02; PPR Staff: Nate Collin |
Mandy Salminen |
| 7/15/2022 |
Site Characterization Workplan Approved |
A work plan was submitted by the RP on July 14, 2022 for a groundwater sampling work plan that follows remedial efforts to pick up released crude oil from the remote gate valve at this location. Three groundwater monitoring wells remain from the earlier investigations related to other historic releases. Groundwater samples will be collected from the three monitoring wells to evaluate the potential migration of hydrocarbons associated with the June 3, 2022 release. An approval for the work plan was sent on this date. |
Laura Jacobs |
| 6/12/2023 |
Document, Report, or Work plan Review - other |
DEC staff reviewed and approved the 2022 Groundwater Monitoring Report and the 2023 Groundwater Sampling Work Plan with the request that the sampled well screen interval be measured and reported. Results from the 2022 monitoring report indicate that petroleum hydrocarbon impacts are present in soils within the corrugated metal pipe (CMP). Soil samples were not collected because of the presence of standing water within the CMP surrounding the gate valve. Groundwater monitoring results all analytes below DEC groundwater cleanup levels or were non-detect. The approved work plan proposes soil excavation and confirmation sampling to address petroleum-impacted soils within the CMP, and another round of groundwater samples from the existing well network. |
Laura Jacobs |
| 7/5/2023 |
Document, Report, or Work plan Review - other |
A work plan was approved to screen and sample the remaining contaminated soils within the corrugated metal pipe (CMP) surrounding the gate valve where in 2021 a leak was found. Over ten soil samples from the floor of the pipe will be screened and the locations where screening reveals a photo-ionization detector (PID) reading above 20 ppm, an analytical sample will be collected and analyzed for gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), polycyclic aromatic hydrocarbons (PAHs), and petroleum volatile organic compounds (PVOCs). Soils removed from the CMP will be screened as well to determine whether to remediate the soils prior to spreading, or spread them across the pad. |
Laura Jacobs |
| 4/12/2024 |
Document, Report, or Work plan Review - other |
DEC reviewed the 2023 RGV-35A Groundwater Monitoring Report received by our office December 19, 2023 and has issued an approval. Despite there being some QA/QC issues with sample results for several polyaromatic hydrocarbons, and as a result the data being rejected, all other aspects of the sample results indicated data usability was not affected. Sample results continue to indicate that historical and recent impacts from crude oil leaks at the RGV-35A have not impacted groundwater beyond the immediate vicinity of the valve within and just downgradient of the corrugated metal pipe containment(CMP). DEC agrees with continued sample collection at the existing groundwater monitoring wells, removal of contaminated soils remaining in the CMP, and determining groundwater flow direction by a level-loop survey in 2024. |
Laura Jacobs |
