| Action Date |
Action |
Description |
DEC Staff |
| 8/14/2013 |
Site Characterization Report Approved |
On this date, ADEC received the 2010 Phase II Site Assessment Report – West Staines State #2 submitted by Weston, dated September 2011 for work conducted in 2010. A total of 145 soil boreholes were advanced to the gravel pad/tundra interface to a depth of 5 feet bgs, including two boreholes advanced within the reserve pit, and at least one soil sample was collected per borehole. The soil samples collected contained GRO up to 623 mg/kg, DRO up to 30,900 mg/kg, RRO up to 4,710 mg/kg, BTEX up to 115 mg/kg, and benzene up to 1.1 mg/kg. Thirteen out of 41 samples analyzed for GRO exceeded criteria, 7 out of 41 for BTEX, 3 out of 41 for benzene, 49 out of 187 for DRO, and 3 out of 187 for RRO. |
Grant Lidren |
| 8/16/2013 |
Site Added to Database |
A new site has been added to the database |
Mitzi Read |
| 8/19/2013 |
Potentially Responsible Party/State Interest Letter |
|
Keather McLoone |
| 8/19/2013 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79497 name: Exxon West Staines State No. 2 |
Grant Lidren |
| 8/25/2014 |
Document, Report, or Work plan Review - other |
Date of receipt of Corrective Action Plan. Review also being conducted by SW and DW programs for issues that fall under their oversight. The plan covers 2 objectives which include obtaining site closure for the contaminated site by removing most of the pad while also removing the fuel contaminated material. This will be accomplished by 1)transporting gravel with DRO >5,000 mg/kg off-site for disposal, 2)placing remaining contaminated gravel (DRO < 5,000 mg/kg but > or = 2,000 mg/kg) in the bottom of the reserve pit, followed by restricted-use gravel to an elevation no higher than one foot below tundra grade, 3) stockpile and sample restricted-use gravel (DRO> 500 but < 2,000 mg/kg) to determine final characterization and disposition. Conditional approval letter sent on 10/6/14 via email clarifying that the condition requesting 100% frequency of GRO/BTEX was for pad confirmation samples only. Hardcopy conditional approval letter also went out on 10/6/14. Lori Aldrich of Solid Waste Program also reviewed and approved this CAP. |
Keather McLoone |
| 12/18/2014 |
Document, Report, or Work plan Review - other |
Reviewing Addendum #1 to the Corrective Action Plan and updating database. The CAP was revised based on comments from DEC CS, DEC SW,and ADNR. All confirmation samples will be tested for BTEX/GRO to better characterize contamination that may be remaining at the site when evaluated for additional action or a change in site status. |
Keather McLoone |
| 1/5/2015 |
Update or Other Action |
Date of receipt of attachments that were intended to have been included with submittal received 12/18/14. |
Keather McLoone |
| 11/20/2015 |
Meeting or Teleconference Held |
Meeting to discuss the results of the Corrective Action plan conducted earlier this year. |
Keather McLoone |
| 11/20/2015 |
Document, Report, or Work plan Review - other |
Date of receipt of Corrective Action Completion Report - West Staines State #2. Based on a site visit made on September 1, 2015 by Exxon representatives and Lori Aldrich of DEC SW, a work plan is being developed to assess drainage from and around the pad and wooden pilings that will be trimmed to grade to include sheen monitoring and sampling. Exxon also proposes to postpone additional site rehab activities. This remedial effort include construction of an ice road and several ice pads including one to support a 63-man camp established for the effort. Following snow and reserve pit ice removal was begun, removal of the gravel pad was started. Material previous characterized as DRO < 5,000 mg/kg (restricted use) was stockpiled for placement in the reserve pit. Conditional use material went on top of restricted use material in the reserve pit. Material > 5,000 mg/kg DRO was stockpiled for transport offsite to the East Dock Landfarm to await transfer to the G&I. Clean gravel from this pad removal and some from the pad removal at WSS #18-9-23 was transported to Point Thompson for reuse, some of which was transported back to WSS #2, again, for backfill. Both composite and discrete confirmation samples were collected with all results below Target levels. Field QC samples were collected from each type of sample whether composite or discrete and whether confirmation or waste characterization.
During the site inspection conducted in summer of 2015, some undisturbed sheen was observed and once the sediments/soils were disturbed additional sheening was observed. These observations were in the area of the reserve pit cap. Further assessment of the sheening will take place in 2016 with a workplan submitted to describe those efforts. Concentrations in confirmation samples up to 0.199 mg/kg benzene, 0.705 mg/kg ethylbenzene, 0.626 mg/kg toluene, 7.06 mg/kg xylenes, 847 mg/kg DRO, 6650 mg/kg RRO, and 278 mg/kg GRO. |
Keather McLoone |
| 12/7/2015 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79497 Exxon West Staines State No. 2. |
Keather McLoone |
| 5/2/2016 |
Document, Report, or Work plan Review - other |
Reviewed the the document entitled 2016 – 2025 Remediation Work at West Staines State #2, West Staines State #18-9-23, dated April 13, 2016. The work plan proposed to collect surface water and co-located sediment samples; however, was missing some details. A revised work plan was requested. The revised work plan was received and approved on May 2, 2015. |
Joshua Barsis |
| 10/5/2016 |
Document, Report, or Work plan Review - other |
Reviewed the Summer 2016 Sheen Inspection & Debris Removal Activities Report, dated September 29, 2016. Activities completed in July 2016 mainly consisted of sheen inspection with and without sediment disturbance, surface water sample collection, and soil sample collection.
Sheen observation was completed along the perimeter of ponded water bodies surrounding the reserve pit. About every 25 feet, the sediment was disturbed and any noticeable sheen was documented. Petroleum hydrocarbon sheens were documented at one location without sediment disturbance, and at eight locations after disturbance. The department acknowledges that an observable sheen violates the Alaska Water Quality Standards (AWQS) regardless of soil disturbance.
Following the sheen inspection and shovel sheen testing activities, four surface water samples were collected based on observable sheen intensity, proximity to other sheens, and size and depth of the surface water body. None of the surface water samples analyzed exceeded the total aromatic hydrocarbons (TAH) and total aqueous hydrocarbon (TAqH) criteria for the AQWS.
Over 30 field screening samples were collected from the soils between 0.5 and 1 foot below pad/tundra surface in the vicinity of observable sheens. In total, 13 soil samples were submitted for laboratory analysis for gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), benzene, toluene, ethylbenzene, and xylenes (BTEX), and polycyclic aromatic hydrocarbons (PAHs). Results revealed various levels of DRO between 17.5 mg/kg and 13,100 mg/kg.
A concentration of 13,100 mg/kg exceeds the ADEC maximum allowable concentration (MAC) of 12,500 mg/kg for DRO and is not acceptable. Further action at this location will be required. Work plan is due February 1, 2017 |
Joshua Barsis |
| 2/10/2017 |
Document, Report, or Work plan Review - other |
Reviewed the Work Plan for Further Delination of Petroleum Hydrocarbons in Soil at West Staines State #2 (WSS #2), dated January 31, 2017. Proposed activities consist of sheen monitoring and additional soil sampling to delineate tundra contamination above Method Two maximum allowable concentrations (MACs). Pending results, and if the estimated volume of contaminated soil exceeds 3 cubic yards, then a Net Environmental Benefit (NEB) analysis will be completed to evaluate the benefits of corrective action against any environmental impacts; such as tundra damage or fuel emissions. |
Joshua Barsis |
| 11/3/2017 |
Document, Report, or Work plan Review - other |
Reviewed the Summer 2017 West Staines State #2 Activities Report, dated October 31, 2017. This field effort was completed in two stages during the summer of 2017 and generally consisted of collecting soil samples from 47 shallow soil borings and collecting surface water samples for comparison to Alaska Water Quality Standards (AWQS). Based on the soil boring sample results, excavation commenced to remove all contamination above Method Two Arctic Zone cleanup levels. Confirmation soil samples were not collected after removal activities.
Results of the 2017 effort concluded that all contamination above Method Two cleanup levels was removed. The highest concentration of diesel range organics (DRO) remaining in the soils at this site is 10,200 mg/kg, however this concentration appears to be isolated and is bounded horizontally. Samples collected from outside of the excavation boundaries had levels of DRO up to 1,380 mg/kg, except for one sample at 4,790 mg/kg; all below the Method Two soil cleanup levels.
About 17.5 cubic yards of impacted soil remains onsite and is planned to be disposed of in winter 2018.
|
Joshua Barsis |
| 1/8/2018 |
Cleanup Complete Determination Issued |
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. |
Joshua Barsis |
