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Site Report: Cornerstone Market Place

Site Name: Cornerstone Market Place
Address: 43977 Sterling Highway, Soldotna, AK 99669
File Number: 2333.38.051
Hazard ID: 25864
Status: Cleanup Complete
Staff: ,
Latitude: 60.486000
Longitude: -151.057200
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.


On February 16, 2012 during a limited Phase II Site Assessment performed on the property, tetrachloroethene soil contamination was detected at 0.150 milligrams per kilogram (mg/kg) at 8 to 8.7 feet below ground surface (bgs) adjacent to the former dry cleaning/laundry mat facility, and at 0.574 mg/kg at 0 to 2.5 feet bgs in the area of the former fuel oil tank location within the current location of the Mullen Court cul-de-sac. Minor detections of diesel range organics (DRO) at 34.8 to 69.6 mg/kg at depths of 0 to 23.3 feet bgs, residual range organics (RRO) at 15.0 to 1,430 mg/kg at 0 to 24 feet bgs, and toluene at 0.0138 mg/kg at 8.0 to 8.6 feet bgs, were detected in the two soil borings taken from the former dry cleaning/laundry mat facility and the former oil tank location within the current location of the Mullen Court cul-de-sac. The site is serviced by the on-site drinking water well drilled to a depth of 76 feet bgs.

Action Information

Action Date Action Description DEC Staff
3/28/2012 Report or Workplan Review - Other Received a Phase I and Limited Phase II site assessment report identifying tetrachloroethene in two soil borings on site. The solvent was identified in shallow soils (2 to 5’) at levels of 0.15 and o.574 mg/Kg. Deeper samples did not detect the solvent. Peter Campbell
4/6/2012 Site Added to Database A new site has been added to the database Alyce Hughey
4/6/2012 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 79280 name: Former Laundry/Dry Cleaning Facility Alyce Hughey
4/16/2012 Potentially Responsible Party/State Interest Letter Drafted a cost recover letter addressed to the property owner requesting a workplan to identify vulnerable water supply wells, the extent of tetrachloroethene in the soil and potentially in the groundwater. Peter Campbell
4/20/2012 Meeting or Teleconference Held Met with the property owner and their consultant. Hand delivered the PRP letter to the property owner and discuss: 1)Cost Recovery. 2) ADEC’s Role. 3) EPA’s Role. 4) ADEC’s expectations for a workplan. 5) Identification of any potentially at risk drinking water wells. 6) Request the identification and extent of solvent impacted soils. Peter Campbell
7/17/2012 Site Characterization Workplan Approved Reviewed and approved the July 17, 2012, Workplan for Site Characterization 43980 Sterling Highway Soldotna, Alaska, prepared by Shannon & Wilson. The workplan approval includes the advancement of one soil boring to approximately 20 feet bgs, one soil boring to approximately 5 feet bgs, and four surface soil samples to determine if the parcel at 43980 Sterling Highway can be transferred without additional characterization and/or remediation. The soil samples collected from the soil boring adjacent to the leachfield will be tested for DRO, RRO, and the sample with the highest field screening result will be tested for GRO and the full suite of VOCs. The remaining soil sample will also be tested for a short list of VOCs including PCE, trichloroethene, cis-1,2-Dichlorothene, vinyl chloride, and toluene. Surface soil samples will be tested for a short list of VOCs including PCE, trichloroethene, cis-1,2-Dichlorothene, vinyl chloride and toluene. Peter Campbell
7/31/2012 Site Characterization Workplan Approved Reviewed and approved the July 19, 2012, Work Plan for Site Characterization 43977 Sterling Highway Soldotna, Alaska, prepared by Shannon & Wilson. The workplan approval includes the advancement of three soil borings to approximately 20 feet bgs, in the area of three septic cribs. Four borings will be drilled to assess the lateral extent of contamination in an area of previously identified PCE contamination on the southwest side of the building. Peter Campbell
10/24/2012 Cleanup Plan Approved Reviewed and approved the October 22, 2012, Corrective Action Plan for 43980 Sterling Highway Soldotna, Alaska, prepared by Shannon & Wilson. This is a northern parcel that is being sold separate from the property that contained the former dry cleaning facility. PCE impacted soils have been found in the City owned right of way. The plan includes the excavation of impacted soils and construction of a passive treatment stockpile for remediation. Peter Campbell
10/30/2012 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 79355 name: 43980 Sterling Highway Peter Campbell
12/14/2012 Site Characterization Workplan Approved ADEC Received a Work Plan for Additional Site Characterization, 43977 Sterling Highway, Soldotna, Alaska on December 13, 2012. The plan includes proposed work for vapor intrusion, vertical and horizontal extent of soil contamination delineation and an initial groundwater investigation. Peter Campbell
2/11/2013 Public Notice ADEC developed an Informational Paper for the Cornerstone Marketplace and distributed it to each of the businesses within the building. The paper described ADEC’s concerns with potential exposure to PCE and TCE, the source of the problem, and actions that ADEC is asking the building owner to undertake in order to understand potential risks. This includes indoor air sampling and further assessment of soil and groundwater impacts. Peter Campbell
3/5/2013 Site Characterization Workplan Approved ADEC approved an indoor air sampling work plan to be conducted under winter conditions. Air samples are to be collected from each business retail space and from in the crawlspace. Samples will be collected in Suma canisters over a 24 hour period and tested for VOC’s. The previously approved work plan, designed to test for groundwater impacts, will be conducted later this year. Peter Campbell
3/22/2013 Site Visit ADEC visited the site to observe the placement of indoor air sampling devices. Peter Campbell
4/24/2013 Report or Workplan Review - Other Six indoor air samples were collected from the Cornerstone Market Place structure. The highest analyte concentrations were detected in the crawlspace which is not occupied. Analyte concentrations of PCE, TCE and cis-DCE, in the occupied portions of the structure were one to two orders of magnitude less that the ADEC target cleanup levels. Peter Campbell
4/24/2013 Site Characterization Workplan Approved Approved the modification of the December 2012 Proposed Scope and Objectives for Additional Site Characterization work plan that eliminates vapor intrusion soil gas sampling and changes the proposed locations of three of the proposed soil borings. Peter Campbell
5/21/2013 Site Visit Visit site to observe monitoring well drilling and sampling activities during the field investigation. Peter Campbell
7/30/2013 Meeting or Teleconference Held Met with the property owner, Aventine Development, environmental and construction consultants. We discussed the results of the drilling investigation, the need for additional assessment work and alternative paths to site closure. We received a draft “Additional Site Characterization” report. Peter Campbell
10/2/2013 Site Characterization Workplan Approved Consultant contacted our office today requesting approval for the installation of three additional groundwater monitoring wells. Approval granted for wells to be installed October 3, 2013. Peter Campbell
10/2/2013 Site Visit Review and approve proposed drilling locations. Peter Campbell
10/25/2013 Report or Workplan Review - Other Received final report titled Additional Site Characterization 43977 Sterling Highway, October 2013. Report details the findings from the installation of 12 soil borings and three monitoring wells that were drilled in May 2013. A level survey was conducted and water samples collected from the monitoring wells. The lateral extent of soil contamination appears to be defined except to the west. The extent of shallow groundwater impacts have not been defined. Peter Campbell
11/5/2013 Meeting or Teleconference Held Meeting to discuss future requirements and the path to site closure with the owner, the consultant and the developer. Peter Campbell
11/7/2013 Offsite Soil or Groundwater Disposal Approved Approval to transport (2) 55 gallon drums of soil and (3) 55 gallon drums of water generated from drill cuttings and monitoring well development to U.S. Ecology's treatment storage disposal facility in Grand View, Idaho. Peter Campbell
11/13/2013 Report or Workplan Review - Other Review work plan proposal and approve plan to install a new monitoring well (MW-6) and collect water samples from on-site wells. Drilling is scheduled for the week of November 18, 2013. Peter Campbell
12/23/2013 Meeting or Teleconference Held Teleconference with the property owner, consultant, developer and ADEC. Discuss requirements for path to closure which will include additional sampling of the newly installed downgradient monitoring well, MW-6. Peter Campbell
1/8/2014 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 79280 43977 Sterling Highway. Alyce Hughey
1/28/2014 Report or Workplan Review - Other Received the report Groundwater Investigation 43977 Sterling Highway Soldotna, Alaska January 2014 detailing the installation of new monitoring wells, sample results, the conceptual site model and an evaluation of the exposure pathways. Peter Campbell
3/17/2014 Cleanup Complete Determination Issued Based on the characterization work completed at this site, ADEC has determined that the residual contamination doesn’t pose an unacceptable risk to human health or the environment. Therefore, we are issuing this Cleanup Complete determination with the following condition: The most current soil sample data provided to ADEC (2012 and 2013) identified tetrachloroethene (PCE) and trichloroethene (TCE) in soil south/southwest of the Cornerstone Market Place building, along the Sterling Highway and Forty Seventh Street, exceeding the current ADEC ‘Migration to Groundwater’ soil cleanup levels. This location of PCE and TCE contaminated soil was estimated and shown on FIG. 1, Shannon & Wilson, January 2014, SITE PLAN, SOIL ANALYTICAL RESULTS (see attachment). Any proposal to transport soil or groundwater off-site requires ADEC approval in accordance with 18 AAC 75.325(i). A “site” [as defined by 18 AAC 75.990 (115)] means an area that is contaminated, including areas contaminated by the migration of hazardous substances from a source area, regardless of property ownership. The excavation of soil on this property in the south/southwest portions of the property may expose contaminated soil requiring proper management, and disposal practices. Any person(s) excavating soil or moving soil or groundwater at this “site” shall contact ADEC and shall provide for the proper handling, treatment, and disposal of any contaminated media encountered in accordance with all applicable ADEC regulations at that time. It should be noted that movement or use of potentially contaminated material in a manner that results in a violation of 18 AAC 70 Water Quality Standards is prohibited. The dry cleaning solvent impacted media (soil & groundwater) associated with this facility may be considered to contain listed hazardous waste, and may be subject to regulation under the Federal Resource Conservation and Recovery Act (RCRA). Listed waste designation is established by source or generating process, not by concentration of wastes or environmental media. The EPA, Region 10 is responsible for administering the Federal RCRA hazardous waste program in the State of Alaska at this time. Any questions concerning the applicability of Federal RCRA requirements to this site should be directed to EPA Region 10. Peter Campbell
6/19/2014 Site Reopened Reopened to review work plans for the management of potentially impacted soils during construction activities. Peter Campbell
6/24/2014 Potentially Responsible Party/State Interest Letter Potentially Responsible Party/State Interest Letter to the new landowner and primary billing party on July 8, 2014 Peter Campbell
10/3/2016 Cleanup Complete Determination Issued The site was reopened to regulate construction activities while the Walgreens was being built. No action was required on the States part. The site is closed, with the conditions and restrictions stipulated in the closure documents. Peter Campbell

Contaminant Information

Name Level Description Media Comments

Control Type

Type Details


Description Details
Advance approval required to transport soil or groundwater off-site.
Movement or use of contaminated material (including on site) in a manner that results in a violation of the water quality standards is prohibited (18 AAC 70)

Missing Location Data

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