Skip to content
Back to Top

Site Report: Alyeska PS 06 Leach Field /Fuel Island


Site Name: Alyeska PS 06 Leach Field /Fuel Island
Address: Mile 55 Dalton Highway, Pump Station 6, Minto, AK 99758
File Number: 330.38.007
Hazard ID: 2965
Status: Active
Staff: Grant Lidren, 9072698685 grant.lidren@alaska.gov
Latitude: 65.854500
Longitude: -149.733333
Horizontal Datum:WGS84

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

In September of 1997, EMCON conducted a site assessment and found diesel range (DRO) and gasoline range organics (GRO) contaminated soil, and suprapermafrost groundwater while digging test pits to install a leach field just north of the fence perimeter at PS 06 (now called Yukon Response Base by Alyeska). Construction of the leach field created a thaw bulb and seems to have caused an increase in contaminant migration. Alyeska operated a Soil Vapor Extraction (SVE) unit from 2000 - 2008. Three potential contaminant sources were identified: 1) the fuel island, 2) the existing tank farm, and 3) the construction-era (1970s) tank farm and generator buildings. The footprint of the petroleum-impacted area encompasses approximately 42,500 square feet and approximately 4,300 cubic yards of petroleum-impacted soil. This area is outside the fenced area of PS 06 - to be differentiated from file number 330.38.074 (Alyeska PS 06 Fueling Area) which is within the fenced portion of the area near the office. Site is located ~6,000 feet south of the Yukon River. 2/26/2014 update: The fuel island has been removed.

Action Information

Action Date Action Description DEC Staff
4/14/2000 Site Ranked Using the AHRM Initial ranking. Deborah Williams
4/20/2000 Site Added to Database GRO, DRO, BTEX and PAH contamination. Deborah Williams
5/9/2000 Update or Other Action Site Characterization Report received. Contamination of MW - 6 (weathered diesel) which is upgradient from the source of contamination in the former construction pad. Benzene-impacted soil and groundwater near the fuel island may be at concentrations that exceed "hazardous waste" levels. Alyeska plans to install an in-situ soil and subsurface water remediation system to reduce benzene levels to below "hazardous waste" levels. Deborah Williams
5/9/2000 Update or Other Action Also from report this date - Construction of the leach field created a thaw bulb and potentially caused an increase in migration of contamination. At the time of this report, Emcon was proposing 10 time the migration to groundwater levels. Boring advanced to install MW-5/VP-2 led to identification of the fuel island as a potential source. Concentrations in soil up to 6,400 mg/kg DRO, 2,700 mg/kg GRO, 9.7 mg/kg benzene, and 159 mg/kg xylenes as well as other BTEX compounds and PAH compounds detected. Concentrations in the wells up to 67 mg/L DRO, 91 mg/L GRO, 13 mg/L benzene, and other BTEX and PAH compounds above Table C levels. Keather McLoone
8/29/2000 Cleanup Plan Approved SVE Workplan Approval Letter drafted. Database notation added by K.McLoone. Deborah Williams
4/13/2001 Cleanup Level(s) Approved Letter acknowleding site information indicates presence of continous permafrost and approving elimination of the migration to groundwater pathway. Database notation added by K.McLoone. Deborah Williams
4/3/2002 Update or Other Action Receipt of Corrective Action Report Pump Station 6 prepared by SLR. Excavation of 300 cubic yds to 2.5-3 ft bgs terminated in frozen soils. Concentrations remaining, based on confirmation samples and soil vapor extraction well installation, up to 18,000 mg/kg DRO, 812 mg/kg GRO, 7.54 mg/kg benzene, 128.9 xylenes, and 58.3 mg/kg toluene. Groundwater results from this effort were consistent with previous results. Keather McLoone
1/30/2003 Update or Other Action Alyeska submitted a SVE Unit Installation and GW monitoring report. According to the report the SVE unit operation during August and September of 2002 has effectively removed approximately 130 pounds of TPH from the soil in the vicinity of the fuel island. SLR recommends the reinstallation of the SVE unit for the operation during 2003. Deborah Williams
5/1/2003 Update or Other Action Alyeska submitted a Remediation and GW Monitoring workplan for 2003. Deborah Williams
3/30/2004 Update or Other Action ADEC received SLR's report entitled 2003 Water Monitoring and Remediation Report Pump Station 6. The SVE operating system from June to October 2003, effectively removed 292.9 pounds of product from the soil near the fuel island and pump building. Added to the recovery total from 2002 of 128 pounds of TPH-G, the SVE unit has recovered approximately 421 pounds of TPH-G to date. This amount is approximately 25% of IT's original estimate of 1700 pounds of product within the soil near the fuel island, 70% of which was estimated to be recoverable in three field seasons. They estimate a total benzene removal from the fuel island vicinity of approximately 3.9 pounds. They recommend that operation of the system continue in 2004. Based on the results obtained during the 2003 suprapermafrost groundwater monitoring event, it is evident that low level concentrations of petroleum hydrocarbons still exist in the suprapermafrost groundwater at this site but is stable or decreasing in nature. The detectable concentrations of DRO and naphthalene found in WP-5, the off-site well point, were below recommended ADEC water quality guidelines. SLR recommends that the suprapermafrost groundwater, both on and off the pad at PS6, be monitored. A minimum of one water sampling event should be conducted during the summer of 2004. Deborah Williams
3/3/2005 Update or Other Action ADEC received SLR's report for the 2004 Water Monitoring and Remediation at PS 6. The SVE unit (operated June through Oct. 2004) removed an estimated 441 pounds of TPH-g from the soil near the fuel island of PS 6. The cumulative TPH-G recovery from 2002 to date is 862 pounds. Benzene removal has decreased significantly since 2001. Benzene removal for 2004 is estimated to be 0.71 pounds, an 80 percent reduction from the 2003 removal estimate of 3.1 pounds. The total benzene removal to date is estimated as 4.6 pounds. Based on the data gathered during 2004, petroleum hydrocarbons still exist in the suprapermafrost groundwater, both on and off pad. However, the concentrations appear to be stable. The off-pad petroleum hydrocarbon concentrations do not exceed surface water quality criteria. Deborah Williams
2/6/2006 Update or Other Action ADEC received the 2005 Remedial Activities and Water Monitoring Report for PS 6. Approximately 144 pounds of TPH-G was removed from the soil near the fuel island with SVE treatment from June 17 to Oct. 13, 2005. The cumulative TPH-G recovery at PS 6 from 2002 to date is 1,006 pounds. This quantity represents approximately 59 percent of the original estimate. SLR recommends continued use of the SVE treatment system. They also recommend sampling the groundwater in 2006 at a earlier time period because of low water levels found in September. Deborah Williams
2/16/2007 Update or Other Action ADEC reviewed the SLR report entitled "Final 2006 Remedial Activities and Water Monitoring Report, Pump Station 6". According to the report, approximately 134.9 pounds of TPH-G was removed from soil near the fuel island with SVE treatment from June 15 to October 10, 2006. the cumulative TPH-G recovery at PS06 from 2002 to date is approximately 1,141 pounds (represents 67% of the original estimate of 1,700 pounds of GRO in-situ). Benzene has decrease significantly since 2001. There were no benzene concentrations above laboratory detection limits in air samples collected in 2006. Based on September groundwater results and results from previous sampling events, significant concentrations of petroleum hydrocarbons still exist in suprapermafrost water on the pad at monitoring wells MW-4 and MW-14. GRO and benzene concentrations in groundwater at SVE-1 which is the closest monitoring well to the SVE system have declined significantly since SVE operation began and are below ADEC screening levels. DRO remains. Deborah Williams
3/2/2007 Exposure Tracking Model Ranking Initial ranking completed. Deborah Williams
6/12/2007 Site Characterization Workplan Approved Receipt of SLR workplan dated May 2007 proposing SVE reinstallation, confirmation borings, and groundwater sampling. Approved by DEC signature. Database notation added by K.McLoone. Deborah Williams
3/7/2008 Update or Other Action Received Pump Station 6 Fuel Island 2007 Remedial Activities, Site Characterization, and Water Monitoring Report. The SVE system operated from June 14 to October 8 and recovered 0.12 pounds of benzene which compares to less than detectable in 2006, 0.4 pound in 2005, 0.71 pound in 2004, and 3.1 pounds in 2003. The 2001 estimate of benzene was less than 17 pounds (based on assumption benzene = one percent of GRO). Nine soil borings were advanced in the fuel island and former fuel bladder tank farm area to characterize the soil in the area of SVE influence and delineate extent to the west below tank farm. Maximum GRO concentration was 6.83 mg/kg and benzene was nondetect in all samples. Prior to SVE operation concentrations were up to 2,700 mg/kg GRO and 9.7 mg/kg benzene. Based on results of soil boring and SVE recovery, SLR recommends SVE operation to be discontinued and requests a NFRAP determination with long-term groundwater monitoring. Four groundwater samples were collected in 2007 from 2 wellpoints and 2 wells. Well samples had DRO concentrations up to 59.1 mg/L DRO and 9.28 mg/L RRO which represent the highest concentrations obtained from these wells. QA/QC review conducted. Keather McLoone
6/10/2008 Update or Other Action Approved Pump Station 6 Trans Alaska Pipeline System 2008 Remedial Action and Water Monitoring Work Plan received May 30 2008. Keather McLoone
2/12/2009 Update or Other Action Date receipt of Pump Station 6 Fuel Island 2008 Water Monitoring Report. Water sampling was conducted at 4 monitoring wells and one well point and SVE wells were converted to monitoring wells (but were not sampled). DRO and RRO above Table C in MW-4 and MW-14. These wells are near the pad edge and TAH and TAqH values for this suprapermafrost water were slightly above DEC water quality standards. A sheen was observed in the surface water near WP-5. If this surface water is present in 2009, it will be sampled along with the ongoing monitoring locations. White ogranisms found in MW-4 and MW-14 will also be investigated (according to SLR). Report review included laboratory review checklists. DRO result for MW-13 should be considered estimated with a low bias due to low surrogate recovery (although a dilution was performed, it was a 1:5 dilution and they should have been able to recover 50 percent of the surrogate). Alyeska requested a cleanup complete with ICs decision as they had last year. DEC will respond with a report approval letter. Keather McLoone
2/26/2009 Update or Other Action Date of DEC report approval letter to state "ADEC will not be making a site status change at this time, but will consider a site status decision after reviewing results that will be reported following 2009 efforts." Keather McLoone
5/20/2009 Report or Workplan Review - Other Approval of Pump Station 6 Fuel Island 2009 Water Monitoring Plan. One groundwater event is planned. If surface water is found near WP-5, one or more surface water samples will be collected (a sheen was observed in this area in 2008). Keather McLoone
4/16/2010 Report or Workplan Review - Other Review of Yukon Response Base Fuel Island 2009 Water Monitoring Report received 4/1/2010. Review included laboratory data review checklist. Only one well and 2 well points contained enough water to be sampled in 2009. A surface water location was also sampled. DRO concentrations remain above Table C for DRO but GRO, DRO, and RRO have decreased from past highs recorded in 2005 and 2007. TAH and TAqH results were calculated because this water is sometimes below surface but may surface downgradient assisting at looking at data trends. The well point locations and the surface water location did not exceed Table C and/or water quality criteria. SLR recommends sampling earlier in the summer or as an opportunity presents itself after a period of significant precipitation in order to increase the probability of having sufficient water (and more wells) to sample. Keather McLoone
5/27/2010 Report or Workplan Review - Other Review of Yukon Response Base Fuel Island 2010 Groundwater Monitoring Workplan. A single event to sample groundwater at 16 locations is planned for late spring/early summer. Keather McLoone
5/20/2011 Report or Workplan Review - Other Date of receipt of Yukon Response Base Fuel Island 2010 Water Monitoring Report. Review included laboratory data review checklist. Only one monitoring well was sampled due to insufficient water in the other wells. Sampling was done in September, rather than late spring/early summer as stated in the workplan. DRO and RRO were detected in the groundwater at MW-4 at levels higher than Table C. Keather McLoone
6/9/2011 Report or Workplan Review - Other Date of receipt of Yukon Response Base Fuel Island 2011 Water Monitoring Workplan. A single event is planned. DEC approval conditioned upon an attempt to sample during a season other than fall. Keather McLoone
3/5/2012 Report or Workplan Review - Other Date of receipt of 2011 Water Monitoring Report. Only well sampled was MW4 which was above Table C for benzene, DRO and RRO. Keather McLoone
6/19/2012 Site Characterization Workplan Approved Approval was conditioned upon a request to sample in a season other than fall since insufficient water volume in the fall has repeatedly impaired sampling efforts. Only one well was successfully sampled in 2011 (for a variety of reasons), so installation of additional wells might be warranted. Richard Bernhardt
11/13/2012 Meeting or Teleconference Held Met with Alyeska (Jan Shifflett) and SLR International (Scott Rose) about characterization at this site. MW-13 is damaged, but it rarely provides enough water to sample. Replacement with another well, located nearby, might be a better option than reparing this well. Installation of multiple, temporary wells might be needed to help determine the plume's boundaries. Only MW-4 has provided enough water to sample in recent years. Richard Bernhardt
1/2/2014 Site Characterization Report Approved On this date, ADEC received the 2013 Water Monitoring Sampling Report Yukon Response Base Fuel Island submitted by SLR dated December 2013. Only the four MWs: MW-2, MW-4, MW-7, and MW-14; and well point WP-5R contained sufficient water for sampling. MW-2, MW-4, and WP-5R were sampled for GRO, DRO, RRO, BTEX, and PAHs. MW-7 and MW-14 were only sampled for GRO and BTEX due to insufficient water recharge. None of the wells contained contaminants above ADEC cleanup levels except MW-2 and MW-4. MW-2 contained DRO up to 8.56 mg/L and RRO up to 1.68 mg/L. MW-4 contained DRO at 3.31 mg/L. GW was encountered 10 to 19 feet bgs. (note: samples are considered bias low due to: a cooler temp of 6.2o C; bubbles greater than 6mm in the three vials for GRO/BTEX, DRO, and the DRO and RRO; and MW-2 contained PH above the method requirement and the primary and duplicate RPDs were outside the precision criteria.) Grant Lidren
2/26/2014 Meeting or Teleconference Held Meeting held with SLR and Alyeska on this date. According to Alyeska, the fuel island has been removed Grant Lidren
5/27/2014 Site Characterization Workplan Approved On this date, ADEC approved the 2014 Water Monitoring Work Plan Yukon Response Base Fuel Island submitted by SLR, dated April 30, 2014. Grant Lidren
1/9/2015 Site Characterization Report Approved On this date, ADEC received the 2014 Water Monitoring Sampling Report Yukon Response Base Fuel Island submitted by SLR dated December 2014. Only the five MWs: MW-2, MW-4, and MW-14; and well points WP-4R and WP-5R contained sufficient water for sampling. MW-2, MW-4, WP-4R, and WP-5R were sampled for GRO, DRO, RRO, BTEX, and PAHs. MW-14 was only sampled for BTEX, GRO, and DRO due to insufficient water recharge. All of the wells contained contaminants above ADEC cleanup levels with DRO from 2.07 mg/L to 29.3 mg/L and RRO from 1.09 mg/L to 4.74 mg/L. GW was encountered 10 to 19 feet bgs. A surface water sample collected from a flowing surface water channel located 10 ft. NW of WP-5R did not contain TAH or TAqH above water quality criteria. Grant Lidren
5/27/2015 Site Characterization Workplan Approved On this date, ADEC received the 2015 Water Monitoring Work Plan Yukon Response Base Fuel Island submitted by SLR dated May 2015. Grant Lidren
3/18/2016 Site Characterization Report Approved On this date, ADEC received the 2015 Water Monitoring Sampling Report Yukon Response Base Fuel Island submitted by SLR dated March 2016. Only monitoring wells MW-2 and MW-4 contained sufficient water and were sampled for GRO, DRO, RRO, BTEX, and PAHs. MW-15 could not be located. It is suspected the well may have been destroyed during road construction in 2013. Groundwater samples collected from MW-2 and MW-4 contained DRO of 2.66 mg/L (duplicate was 1.18 mg/L therefore this sample is considered estimated) and 8.35 mg/L respectively. GW was encountered 16.63 to 18.90 feet bgs. No surface water samples were collected due to absence of surface water in the natural drainage. Grant Lidren
5/31/2016 Site Characterization Workplan Approved The Alaska Department of Environmental Conservation (ADEC) Contaminated Sites Program (CSP) has received and reviewed the 2016 Water Monitoring Work Plan Yukon Response Base Fuel Island submitted by SLR and dated May 2016. ADEC has no objections to the Work Plan and SLR may proceed. Grant Lidren
3/28/2017 Site Characterization Report Approved On this date, ADEC received the 2016 Water Monitoring Sampling Report Yukon Response Base Fuel Island submitted by SLR dated January 2017. Four out of the eight monitoring wells (MW-2, MW-4, MW-7, MW-14) and one out of the six well points (well point WP-4R) were sampled for GRO, DRO, RRO, BTEX, and PAHs. There was not sufficient water in the other MWs and WPs for sampling. Well point WP-4R did not contain contaminant concentrations above ADEC cleanup levels. All the monitoring wells contained contaminant concentrations above cleanup levels with DRO up to 21.5 mg/L (MW-4) and RRO up to 1.82 mg/L(MW-4). MW-7 located furthest north of the site contained DRO at 1.62 mg/L. No surface water samples were collected due to absence of surface water in the natural drainage. Grant Lidren
6/5/2017 Site Characterization Report Approved The Alaska Department of Environmental Conservation (ADEC) Contaminated Sites Program (CSP) has received and reviewed the 2017 Water Monitoring Work Plan Yukon Response Base Fuel Island submitted by SLR and dated May 2017. This work plan is affective for three years of sampling: 2017, 2018, and 2019. PAHs sampling will be discontinued. For at least 2017, MW-4 will be analyzed for petroleum VOCs by 8260. Grant Lidren

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details

Requirements

Description Details

There are no documents for this site report.

Missing Location Data

Because the GIS location data for this site has not been entered, we cannot direct you to its position on the map. Click "Continue" to proceed to the Contaminated Sites Web Map or "Close" to return to the site report.
Continue     Close