| Action Date |
Action |
Description |
DEC Staff |
| 11/17/2011 |
Potentially Responsible Party/State Interest Letter |
Potentially Responsible Party letter sent for the water samples collected from seeps adjacent to the fuel terminal on September 19, 2011 containing concentrations of hydrocarbons above ADEC Groundwater cleanup levels. |
Bill O'Connell |
| 11/18/2011 |
Site Added to Database |
A new site has been added to the database |
Alyce Hughey |
| 11/18/2011 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79215 name: Above Ground Tank Farm |
Alyce Hughey |
| 8/20/2012 |
Document, Report, or Work plan Review - other |
Reviewed the Outfall Pipe Location and Sampling Report, dated July 18, 2012, from Conestoga-Rovers & Associates. On June 5, 2012 a subsurface investigation using an excavator to locate the oil water separator outfall piping was conducted. Two soil samples were collected where the continuous pipe terminates, one at the bottom of the excavation and one on the sidewall of the excavation, with DRO at 371 mg/kg at 3 feet bgs, and benzene at 0.045 mg/kg at 4 feet bgs. One soil sample was collected north of where the continuous pipe terminates, with DRO at 503 mg/kg and benzene at 0.60 mg/kg at3.5 feet bgs. Further excavation south of where the continuous pipe terminated, a destroyed piping terminus near the southern property boundary was found, and one soil sample and one grab groundwater sample was collected, with benzene at 0.29 mg/kg at 1 feet bgs and groundwater with DRO at 7.7 mg/l, GRO at 3.3 mg/l and benzene at 0.31 mg/l. PAH’s were detected in the soil samples collected but not above the ADEC soil cleanup levels. The samples were collected at shallow depths and collected in an area where the local storm water drainage accumulates. The contamination is likely from historical impacts, current activities and storm water drainage near the site. Field screening results did not detect petroleum hydrocarbon impacted soil; therefore, the soil and fill material removed was reused as backfill. |
Alyce Hughey |
| 3/26/2013 |
Document, Report, or Work plan Review - other |
Reviewed the Soil Chracterization Report, dated January 18, 2013, prepared by Conestoga-Rovers & Associates. A new source area ID 79420 was generated for this area of contamination. On June 21 through June 27, 2012, during the excavation of a footprint for a new truck loading rack, consisting of six footings and a trench surrounding the footprint, three two-inch galvanized steel lines were encountered in the northwest corner of the excavation. The lines were not in service, but contained a small amount of LNAPL. Contaminated soil and groundwater was encountered at a depth of 2.5 feet below ground surface. Soil samples collected at 2.5 feet bgs detected benzene at 0.486 to 93 mg/kg, ethylbenzene at 7.780 to 298 mg/kg, toluene at 7.780 to 1,110 mg/kg, xylenes at 219.10 to 1,506 mg/kg, GRO at 340 to 9,980 mg/kg, and DRO at 989 to 25,000 mg/kg. The grab groundwater samples collected within the excavation detected DRO at 2.07 mg/L. Monitoring well MW-5 installed in this area for the Dillingham Auto site was decommissioned during the excavation, and then on September 13, 2012 monitoring well MW-5R was installed to replace MW-5. Approximately 545 tons of impacted soil was removed during the excavation and temporarily stored on-site in supersacks. On July 16, 2012, ADEC approved for the transport and disposal of the contaminated soils to Columbia Ridge Landfill in Arlington, Oregon with the condition that certificates and disposal and waste manifests be presented to ADEC. On September 25th through September 27th, 2012 twenty-three containers were loaded with 180 supersacks (approximately 545 tons of soil) for transport to Columbia Ridge Landfill in Arlington, Oregon. |
Alyce Hughey |
| 3/26/2013 |
Offsite Soil or Groundwater Disposal Approved |
Paul Horwath approved for the transport of contaminated soil on July 16, 2012, for the transport and disposal of the contaminated soils to Columbia Ridge Landfill in Arlington, Oregon with the condition that certificates and disposal and waste manifests be presented to ADEC. On September 25th through September 27th, 2012 twenty-three containers were loaded with 180 supersacks (approximately 545 tons of soil) for transport to Columbia Ridge Landfill in Arlington, Oregon. |
Alyce Hughey |
| 3/26/2013 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79420 name: Truck Loading Rack |
Alyce Hughey |
| 12/31/2013 |
Spill Transferred from Prevention Preparedness and Response Program |
On April 20, 2012 approximately 300-gallons of Jet Fuel (#1 Diesel) spilled as the result of an improperly installed pressure relief valve located on the facilities jet fuel piping, causing the threads to break. The jet fuel migrated from the broken pipe valve to the seawall along the snow covered surface, down through the soil and out the holes of the seawall and into the Nushgiak River were a sheen was observed. Cleanup measures conducted under the direction of the Prevention and Emergency Response Program included the isolation of the pressure relief valve line to stop the flow of fuel. The placement of a sorbent boom to catch the product on top of and at the bottom of the beach. The jet fuel contaminated snow was removed and placed in fast tanks to melt the snow and recover the fuel, and the contaminated gravel was also removed and placed into drums. On September 28, 2012 surface soil samples were collected on the north and south sides of the seawall. DRO was detected at 858 to 2,270 mg/kg on the north side of the seawall at 0.5 feet bgs, and no petroleum hydrocarbons were detected above ADECs Table B1, Method Two “Migration to Groundwater” cleanup levels underneath the holes on the south side of the seawall. Indicating that petroleum hydrocarbons do not appear to remain near the beach. On September 10 and 11, 2013 approximately 3 cubic yards of impacted soil was excavated from the north side of the seawall and transported to ASR for thermal remediation and disposal. Confirmation soil samples collected at the excavation bottom at 2.5 feet bgs detected DRO at 1,190 mg/kg. Samples collected along the excavation northern sidewall at 1 feet bgs, detected DRO at 1,080 mg/kg and samples collected next to the seawall at 1 feet bgs detected DRO at 1,140 and 1,270 mg/kg. Further excavation was not feasible due to crushed rock and boulders. Residual DRO soil contamination remains in the surface and subsurface soils along the northern side of the seawall at concentrations of 1,080 mg/kg to 1,270 mg/kg at depths of 1 to 2.5 feet bgs. |
Alyce Hughey |
| 1/15/2014 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79580 name: Jet Fuel Pressure Release Valve |
Alyce Hughey |
| 12/29/2014 |
Document, Report, or Work plan Review - other |
Review of Soil Sampling Report (November 13, 2014) summarizing stockpile sampling and surface soil sampling conducted during August 2014 excavation in secondary containment for work conducted east of Tank 10. approximately 600 cubic yards and 15 super sacks of petroleum impacted soils were stockpiled pending disposal in the spring of 2015.
Excavation sampling there is DRO and benzene contamination remaining in the ground in concentrations that exceed migration to groundwater. The source area has not been identified. |
Peter Campbell |
| 8/6/2015 |
Document, Report, or Work plan Review - other |
Review of Soil Contamination Report and send letter to Delta Western requesting they install a monitoring well network capable of determining the extent of hydrocarbon impacts. |
Peter Campbell |
| 3/17/2016 |
Site Characterization Workplan Approved |
Approved a work plan, prepared by consultant GHD, to re-sample an ~600 cubic yard stockpile of contaminated soil, which was excavated during tank farm expansion work in 2014. |
Paul Horwath |
| 3/18/2016 |
Update or Other Action |
After reviewing monitoring well results from an adjacent site (Dillingham Auto) ADEC has reiterated our requirement for a monitoring well network that is capable of determining if discharges from the tank farm are impacting the Nushagak River. In addition, because MW-11 is the closest monitoring well to the river, and it is contaminated, we have asked Delta Western submit a cleanup plan to prevent the continuing migration of contaminated groundwater into the Nushagak River by May 15, 2016. |
Peter Campbell |
| 3/23/2016 |
Meeting or Teleconference Held |
Phone conference with project consultant discussing ADEC's requirement for a work plan and corrective action plan at the tank farm site. Reviewed ADEC's goals of establishing a monitoring network between the tank farm and the Nushagak River, and around the perimeter of the tank farm. We also reiterated our requirement for a corrective action plan to stop impacts to the River. |
Peter Campbell |
| 3/25/2016 |
Document, Report, or Work plan Review - other |
Letter acknowledging the receipt of a work plan for the installation of two monitoring wells to the east of the tank farm. The letter noted that the two proposed wells will not help characterize groundwater impacts to the south of the tank farm, along the Nushagak River. |
Peter Campbell |
| 4/28/2016 |
Site Characterization Workplan Approved |
Work plan approved for the installation of six new groundwater monitoring wells. Two of the new wells will be located on the tidal flats south of the tank farm. We have advised Delta Western that we will managing contamination that may be hydraulically connected with surface water on the south side of the tank farm. |
Peter Campbell |
| 5/4/2016 |
Update or Other Action |
Delta Western requested and was granted an extension until June 20, 2016 for preparing a work plan to address remediation at the site. The consultant is currently conducting assessment work on site. |
Peter Campbell |
| 7/21/2016 |
Update or Other Action |
Issued Soil Transport Form for 600 cubic yards and 15 super sacks of DRO impacted soils. The soil it to be transported to MSW Landfill in Washington this September. The project is over seen by GHD Consulting. |
Peter Campbell |
| 9/15/2016 |
Update or Other Action |
Contaminated soil stockpile was larger than anticipated. The majority of the stockpile was put into containers for transport off site, but 130 to 140 cubic yards of material was left in the stockpile. The consultant noted that the material did not have elevated PID detections and has proposed to conduct additional screening and sampling prior to making a decision on the fate of the remaining material. The 140 yards of stockpiled soil and soils in containers will undergo further sampling. |
Peter Campbell |
| 9/26/2016 |
Site Characterization Workplan Approved |
Review Monitoring Well Installation Report and First Semiannual Groundwater Sampling Report 2016 and Draft Site characterization Work Plan (June 2016). Approved the work plan in a September 26, 2016 letter with some additional recommendations. |
Peter Campbell |
| 9/28/2016 |
Update or Other Action |
Teleconference with owner and consultant discussing contaminated soil container and stockpile sampling. |
Peter Campbell |
| 3/14/2017 |
Update or Other Action |
Review Soil Stockpile Disposal Report that discusses the movement of stockpiled soils to 35 open topped shipping containers. An estimated 250 cy of stockpiled soil remained at the site. |
Peter Campbell |
| 2/12/2018 |
Document, Report, or Work plan Review - other |
Reviewed the Site Characterization Report dated December 1, 2017. Responded with Comments to Delta Western on February 12, 2018 requiring a work plan that address monitoring well sample methods and analysis that include VOC and SVOC compounds, monitoring wells within the tank farm and reiterated the need to address impacts to Nushagak River. |
Peter Campbell |
| 6/22/2018 |
Document, Report, or Work plan Review - other |
Review and approve a work plan for the installation of three monitoring wells within the fuel storage tank farm. |
Peter Campbell |
| 6/25/2018 |
Document, Report, or Work plan Review - other |
Reviewed the October 2017 Semiannual Groundwater Monitoring Report for the tank farm.
There are three areas of elevated hydrocarbons. A former UST location north of the tank farm and west of the former Dillingham Auto building has DRO, GRO and benzene. A second area is west of the Delta Western Office Building with elevated DRO. The third area is south and west of the tank farm, with the highest DRO and benzene concentrations around the pump house. Benzene is present in the monitoring wells south of the tanks farm and in the tidal zone of the Nushagak River. Groundwater flow is the south-southwest with a gradient of 0.02 feet per foot in the north to 0.12 feet per foot in the south.
|
Peter Campbell |
| 7/19/2018 |
Update or Other Action |
Approve land spreading of remaining 250 cubic yards of stockpiled material on site around the concrete pad form the old station. |
Peter Campbell |
| 8/27/2018 |
Update or Other Action |
Review report on the land spreading of approximately 180 cubic yards of soil around the perimeter of a concrete pad on site. The soils were spread an average of 1.5 feet thick, fertilized and covered with erosion control material and seeded. |
Peter Campbell |
| 2/5/2019 |
Meeting or Teleconference Held |
Meeting with Delta Western to discuss the 2018 report, site conditions and path forward. |
Peter Campbell |
| 4/10/2019 |
Document, Report, or Work plan Review - other |
Review the 2018 Monitoring Well Installation and Groundwater Monitoring Report. Water discharge from the site to the Nushagak River exceeds surface water cleanup requirements of TAH and TAqH. ADEC has requested a work plan by July 1, 2019 for corrective actions. |
Peter Campbell |
| 7/26/2019 |
Site Characterization Workplan Approved |
Approve 2019 work plan for additional groundwater monitoring in preparation for remediation work in 2020. |
Peter Campbell |
| 3/11/2020 |
Document, Report, or Work plan Review - other |
The analytical results of the October 2019 groundwater monitoring event are consistent with the
analytical results of other monitoring events over the last several years. The nature and extent of
dissolved petroleum hydrocarbons in groundwater at the Site also support the conclusion that the
impacts to groundwater are the result of multiple releases rather than a single release. Benzene was detected at concentrations exceeding ADEC Table C cleanup levels in groundwater
samples collected throughout the Site during the October 2019 monitoring event, with the highest
concentrations detected in groundwater samples collected from monitoring wells on the
southwestern portion of the Site west of the pump house, near the former truck loading rack, and
adjacent to and down-gradient of the former underground storage tank at the former Dillingham
Auto fueling facility (Figure 4). Elevated benzene concentrations also have been detected in
groundwater samples collected from monitoring well MW-7, which is not near any obvious
potential historical source. VOCs and PAHs were detected at concentrations exceeding ADEC Table C cleanup levels during the October 2019 monitoring event. Water discharging from the seep that has been observed near the southwestern corner of the Site was sampled to determine TAH and TAqH concentrations for comparison to ADEC water quality standards. The TAH and TAqH concentrations of 683.9 and 689.4 µg/l, respectively, calculated for the seep water sample collected during the October 2019 monitoring event exceeded the TAH and TAqH criteria of 10 and 15 µg/l, respectively, for petroleum hydrocarbons, oils, and grease for marine water uses for growth and propagation of fish, shellfish, other aquatic life, and wildlife in 18 AAC 70.020(b)(17)(C). The majority of the TAH and TAqH values calculated for the seep
sample collected during the October 2019 monitoring activities are due to the concentrations of
benzene (318 µg/l) and xylenes (258 µg/l) in the sample. TAH and TAqH concentrations of 773.5
and 778.1 µg/l, respectively, were previously calculated for the seep water sample collected at the
same location during the September 2018 monitoring event at the Site. |
Peter Campbell |
| 6/18/2020 |
Document, Report, or Work plan Review - other |
Reviewed and approved the 2020 Interim Removal Action Work Plan. The plan calls for the installation of a permeable reactive barrier between the source areas and the river. Four new monitoring wells are to be installed. |
Peter Campbell |
| 11/12/2020 |
Update or Other Action |
Delta Western has completed the interim removal action, subsurface injections, groundwater and seep monitoring. Due to the COVID-19 pandemic, the work was conducted in mid-September. Because the implementation of the interim action was delayed until late September, Delta Western proposes postponing the 2020 performance monitoring event and conducting site-wide and performance monitoring events in 2021. |
Peter Campbell |
| 4/23/2021 |
Document, Report, or Work plan Review - other |
Review and approve Interim Removal Action Report. Request that the consultant monitor retaining wall drains for flowing water and collect samples if possible. |
Peter Campbell |
| 8/1/2022 |
Update or Other Action |
On June 28 and 29, 2022, Farallon conducted an assessment of relative concentrations of suspended carbon in groundwater samples where visible evidence of suspended carbon was observed in groundwater samples collected in 2020 and 2021 following the interim remedial action injection of PetroFix in September 2020. The monitoring wells for the suspended carbon assessment included MW-10, MW-11R, MW-16, MW-27, MW-29, and MW-30. Groundwater samples were collected in clear sampling vials and visually compared to a 50 milligrams per liter (mg/l) PetroFix standard provided by Regenesis, the manufacturer of the Petrofix product. The assessment was conducted to evaluate whether mitigation activities may be required to obtain representative groundwater samples. Regenesis has indicated that based on their experience, suspended carbon material from Petrofix injections at concentrations less than 50 mg/l should not have a significant effect on dissolved-phased petroleum hydrocarbons concentrations in groundwater samples.
Using the visual comparison method, none of the samples exceeded the 50 mg/l benchmark. The amount of suspended carbon in groundwater following the 2020 injection activities continues to decline based on visual observations. Additional details on the carbon assessment will be included in the 2022 groundwater monitoring report.
|
Peter Campbell |
| 8/10/2022 |
Document, Report, or Work plan Review - other |
Reviewed the 2021 Groundwater Monitoring Report. The concentration of DRO, GRO and BTEX in groundwater samples generally are significantly lower down gradient of the carbon injection relative to concentrations in upgradient wells.
|
Peter Campbell |
| 4/6/2023 |
Long Term Monitoring Workplan or Report Review |
Review the 2022 Groundwater Monitoring Report. It appears that the carbon injection wall is having an effect on downgradient hydrocarbon concentrations in wells. Concentrations in the seep to the Nushagak have decreased but are remain elevated. Concentration in groundwater at MW-23 (Pump House) and MW-24 remain elevated and may benefit from active remediation. |
Peter Campbell |
| 3/28/2024 |
Update or Other Action |
Delta Western, in a Spring 2024 e-mail, proposes to discontinue sampling monitoring wells TW-2; MW-9; MW-15; MW-21; MW-22; and MW-25. These wells have concentrations that have been less than the ADEC cleanup levels or a minor fluctuation that slightly exceeding cleanup levels. The data from these wells also are not critical to evaluation of groundwater quality or decision-making at this time. These wells can be added back to the groundwater monitoring program at a later date. DEC supports this conclusion. |
Peter Campbell |
| 4/1/2024 |
Long Term Monitoring Workplan or Report Review |
Delta Western Dillingham 2023 GWM Report - ADEC Report Approval |
Peter Campbell |
