| Action Date |
Action |
Description |
DEC Staff |
| 8/10/2007 |
Exposure Tracking Model Ranking |
Initial ranking completed. |
Mitzi Read |
| 8/10/2007 |
Site Added to Database |
Site added to the database. |
Mitzi Read |
| 3/14/2008 |
Update or Other Action |
Receipt of Pump Station 1 2007 Former Baseline Shop Contamination Assessment Report. Eight borings were advanced to address historic contamination and attempt to delineate to the extent practical. Soil samples did not contain contaminants greater than the most conservative of arctic zone cleanup levels. Two monitoring wells were installed but only MW-2 contained sufficient water for sample collection. GRO, DRO, and RRO results were 1.84, 12.7, and 2.09 mg/L respectively. VOCs were detected but not above Table C levels. Groundwater monitoring will continue in 2008. Review of report including lab QA/QC conducted 3/25/08. |
Keather McLoone |
| 3/4/2009 |
Document, Report, or Work plan Review - other |
Date of receipt of Pump Station 1 Former Baseline Shop 2008 Ground Water Monitoring Report by SLR. Two monitoring wells were sampled. DRO/RRO above Table C. Cleanup criteria for 1,2,3-dichloropropane lowered with new regs released recently. This compound was reported in MW-2 below the PQL (considered estimated) and above the current Table C level. PQL greater than current Table C level. Monitoring to continue in 2009. |
Keather McLoone |
| 5/22/2009 |
Document, Report, or Work plan Review - other |
Review of Pump Station 1 Former Baseline Shop 2009 Groundwater Monitoring Work Plan. A single groundwater event is planned for late summer/early fall. MW-1 and MW-2 will be sampled and analyzed for GRO, DRO/RRO, and VOCs. |
Keather McLoone |
| 5/7/2010 |
Document, Report, or Work plan Review - other |
Review of Pump Station 1 Former Basline (Shop) 2009 Groundwater Monitoring Report. Two wells were sampled for GRO/DRO/RRO and VOCs in July 2009. Both wells had DRO/RRO above Table C and MW-1 had GRO above Table C. MW-2 also had methylene chloride above Table C. Several issues with lab analysis of VOCs were determined to not have a significant impact on data usability. |
Keather McLoone |
| 6/18/2010 |
Document, Report, or Work plan Review - other |
Review of Pump Station 1 Former Baseline Shop 2010 Groundwater Monitoring Workplan received June 15,2010. A single groundwater event including the 2 onsite wells is planned for when the PS 01 gravel pad is thawed. |
Keather McLoone |
| 3/24/2011 |
Document, Report, or Work plan Review - other |
Date of receipt of Pump Station 1 Former Baseline 2010 Ground Water Monitoring Report. Groundwater exceedances for GRO, DRO, and RRO exist at this site. 1,2,3-trichloropropane was detected above Table C in the duplicate sample at 0.00227 mg/L but the primary sample was non-detect at 0.001 mg/L. |
Keather McLoone |
| 3/24/2011 |
Document, Report, or Work plan Review - other |
Date of receipt of Pump Station 1 Former Baseline 2010 Ground Water Monitoring Report. Groundwater exceedances for GRO, DRO, and RRO exist at this site. 1,2,3-trichloropropane was detected above Table C in the duplicate sample at 0.00227 mg/L but the primary sample was non-detect at 0.001 mg/L. |
Keather McLoone |
| 6/27/2011 |
Document, Report, or Work plan Review - other |
Date of receipt of Pump Station 1 Former Baseline Shop 2011 Groundwater Monitoring Work Plan. Alyeska plans to conduct a single suprapermafrost ground water sampling event in 2011. |
Keather McLoone |
| 2/14/2012 |
Document, Report, or Work plan Review - other |
Date of receipt of 2011 Groundwater Monitoring report. Two wells were sampled and both wells contained DRO and RRO above groundwater cleanup levels. Review included laboratory data review checklist. Followup being conducted via email regarding LOQs not meeting cleanup levels for 1,2,3-trichloropropane and EDB. |
Keather McLoone |
| 6/13/2012 |
Site Characterization Workplan Approved |
2012 Work Plan approved for conducting soil borings, soil sampling, installing and sampling new monitoring wells. Commented on potential site closure. DRO remains approx 40x higher than ADEC cleanup levels, GRO is near cleanup levels and largely static, and RRO is 4-6x higher than cleanup levels. Data for other analytes (1,2,3-trichloropropane and Methylene chloride) were elevated but may represent sample "noise" due to lack of repeatability. Compare to levels next time. |
Richard Bernhardt |
| 2/26/2013 |
Document, Report, or Work plan Review - other |
SLR installed, developed and sampled 4x new monitoring wells (MWs 3,4,5,6) in 2012 for a total of six MWs onsite. Water samples were collected on 1 Aug (one day after the wells were installed). MWs 1,2,4,& 5 exceeded ADEC cleanup levels for DRO, but concentrations in MW-1 were roughly 1/3 of their previous concentration a year prior. The DRO concentration in MW-2 was reduced by a factor of 2.1. This drastic reduction may reflect a greater than expected radius of influence from the sulfate injection pilot study that was conducted approximately 380 ft. to the south southeast. Alternatively, external factors may have affected sample results this year. Future results will help to resolve this uncertainty.
Maximum DRO concentrations were noted in MWs 1,2,4,& 5 with concentrations of 18.6, 14.8, 1.88, and 1.96 mg/L, respectively. No other exceedances were noted.
ADEC requested for VOCs to be sampled by EPA Method 504.1 before entertaining a closure request to confirm that 1,2,3-Trichloropropane and 1,2-Dibromoethane are below regulatory criteria. Limits of detection are above regulatory criteria using EPA Method 8260B. |
Richard Bernhardt |
| 3/14/2013 |
Update or Other Action |
Coordinates verified by comparing 2012 work report to Google Earth imagery. |
Richard Bernhardt |
| 5/24/2013 |
Site Characterization Workplan Approved |
On this date, the Pump Station 1 Former Baseline Shop 2013 Groundwater Monitoring and Investigation Work Plan was recieved. In 2013, a single suprapermafrost GW sampling event will occur following the installation of additional soil borings and wells to further delineate soil and GW Impact. |
Richard Bernhardt |
| 1/2/2014 |
Site Characterization Report Approved |
On this date, ADEC received the 2013 Groundwater Monitoring Report PS 1 Former Baseline Shop submitted by SLR dated December 31, 2013. Groundwater samples were collected from MW-1 to MW-6, in the vicinity of the former baseline shop. All the samples were analyzed for SW8260B and USEPA 504.1. The detection limit for the compound 1,2,3-trichloropropane, analyzed by method SW8260B, was 0.00062 mg/L, which is above the Table C groundwater cleanup level of 0.00012 mg/L. MW-1, MW-2, MW-4, and MW-5 contained DRO up to 31.5 mg/L. MW-1, MW-2, and MW-5 contained RRO up to 2.4 mg/L. PCE was detected in MW-4 at 0.00579 mg/L The GW gradient at the Former Baseline is relatively flat, with a trend towards the south. The 2013 GW elevations were from 1.17 to 1.40 feet higher than in 2012. |
Grant Lidren |
| 5/27/2014 |
Risk Assessment Workplan Approved |
On this date, ADEC approved the 2014 Groundwater Monitoring Work Plan Pump Station 1 Former Baseline Shop submitted by SLR, dated May 2014. |
Grant Lidren |
| 1/9/2015 |
Site Characterization Report Approved |
On this date, ADEC received the 2014 Groundwater Monitoring Report PS 1 Former Baseline Shop submitted by SLR dated December 2014. Groundwater samples were collected from MW-1 to MW-6, in the vicinity of the former baseline shop. Method 504.1 results for EDB and 1,2,3-trichloropropane contain a low bias due the temp blank received by the Network Denver lab at a temp of 12.8 C. MW-3 did not contain detectable concentrations of contaminants. MW-1, MW-2, MW-4, MW-5, and MW-6 contained detectable concentrations of DRO up to 19.3 mg/L. MW-1, MW-2, MW-5, and MW-6 contained detectable concentration of RRO up to 1.61 mg/L. PCE was only detected in MW-2 and MW-4 at 0.0011 mg/L and 0.00646 mg/L respectively. The GW gradient at the Former Baseline is relatively flat, with a trend toward the southwest then to the south. The 2014 GW elevations were from 0.58 to 1.72 feet lower than in 2013. |
Grant Lidren |
| 7/6/2015 |
Site Characterization Workplan Approved |
The Alaska Department of Environmental Conservation (ADEC) Contaminated Sites Program (CSP) has received and reviewed the 2015 Groundwater Monitoring Work Plan Pump Station 1 Former Baseline Shop submitted by SLR and dated June 2015. ADEC has no objections to the Work Plan and SLR may proceed with the following comment: groundwater samples analyzed by AK 102; AK 103; and SW8260B will be preserved with HCL. |
Grant Lidren |
| 3/29/2016 |
Site Characterization Report Approved |
On this date, ADEC received the 2015 Groundwater Monitoring Report PS 1 Former Baseline Shop submitted by SLR dated February 2016. Groundwater samples were collected from MW-1 to MW-6, in the vicinity of the former baseline shop. EDB and 1,2,3-trichloropropane, analyzed by USEPA Method 8260B-SIM, were ND. MW-1, MW-2, and MW-5 contained petroleum constituents above cleanup levels with DRO at 27.4 mg/L and RRO at 2.93 mg/L (MW-1). PCE was only detected in MW-2, MW-4, and MW-6 up to 0.00645 mg/L (MW-4). The GW gradient at the Former Baseline is relatively flat, with a trend toward the southwest then to the south. The 2015 GW elevations were from 0.81 to 1.71 feet higher than in 2014. |
Grant Lidren |
| 2/15/2017 |
Update or Other Action |
On this date, ADEC received the 2016 Groundwater Monitoring Report PS 1 Former Baseline Shop submitted by SLR dated February 2017. Groundwater samples were collected from MW-1 to MW-6, in the vicinity of the former baseline shop. EDB and 1,2,3-trichloropropane, analyzed by USEPA Method 8260B-SIM, were ND. MW-1, MW-2, and MW-5 contained petroleum constituents above cleanup levels with DRO at 16.2 mg/L and RRO at 1.68 mg/L (MW-1). PCE was only detected in MW-2, MW-4, and MW-6 but below the DEC 2016 cleanup levels. The GW gradient at the Former Baseline is relatively flat, with a trend toward the southwest then to the south. The 2015 GW elevations were lower than in 2015 except for MW-2. |
Grant Lidren |
| 7/19/2017 |
Site Characterization Workplan Approved |
On this date, ADEC received and approved the Pump Station 1 Baseline Shop Well and Equipment Shop Well Decommissioning Work Plan submitted by SLR and dated July 19, 2017. |
Grant Lidren |
| 12/5/2017 |
Update or Other Action |
The six onsite monitoring wells were decommissioned during the summer of 2017. |
Grant Lidren |
| 12/5/2017 |
Cleanup Complete Determination Issued |
The Alaska Department of Environmental Conservation, Contaminated Sites Program (ADEC) has completed a review of the environmental records associated with Alyeska Pump Station (PS) 01 Former Baseline Shop. 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 new information becomes available that indicates residual contaminants may pose an unacceptable risk. |
Grant Lidren |
