| Action Date |
Action |
Description |
DEC Staff |
| 6/11/2015 |
Spill Transferred from Prevention Preparedness and Response Program |
Spill transferred by PERP staff Megan Kohler. Spill no. 14239919501; spill date = 7/14/14; substance = petroleum; quantity = unknown; description: Petroleum contamination encountered during site assessment, source is unknown. |
Mitzi Read |
| 6/18/2015 |
Site Added to Database |
A new site has been added to the database |
Mitzi Read |
| 6/18/2015 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79778 name: Commercial Property - 900 East Dowling Road |
Mitzi Read |
| 6/25/2015 |
Potentially Responsible Party/State Interest Letter |
Letter of state interest sent. |
Joshua Barsis |
| 7/1/2015 |
Document, Report, or Work plan Review - other |
Reviewed several site reports (dated April 2014, June 2014, August 2014, and May 2015). Summary of site activities and review up to this date: A Phase I Environmental Site Assessment (ESA) was completed at the site in April of 2014. The Phase I ESA identified the historical use of the property as an automotive junkyard, warranting further investigation. A Limited Phase II ESA was performed on May 9, 2014 in an effort to characterize the site. A total of 29 soil samples were collected from six soil borings advanced at the property. Each soil boring was advanced through asphalt, to a maximum depth of 12 feet below ground surface (bgs). Soil types generally consisted of a mixture of sands, gravels, and organics (peat) down to at least 10 feet bgs, followed by a thick silt layer. Groundwater was not encountered. Based on field screening, visual evidence of contamination and odors, six soil samples were selected for laboratory analysis of gasoline range organics (GRO), diesel range organics (DRO), residual range organics (RRO), volatile organic compounds (VOCs), polynuclear aromatic hydrocarbons (PAHs), and RCRA Metals. Additionally, select samples were also analyzed for DRO and RRO using silica gel cleanup to evaluate potential biogenic interference from the organic material. In addition to the soil samples, a water sample was collected from the property DWW and was submitted for laboratory analysis of VOCs and arsenic. Laboratory results revealed that DRO was present in the subsurface soils above the ADEC migration-to-groundwater (MTG) cleanup level in one sample (Sample SB2). The concentration of DRO from Sample SB2, prior to silica gel cleanup, was 559 milligrams per kilogram (mg/kg). After silica gel cleanup, the concentration of DRO decreased to 319 mg/kg, still exceeding the ADEC MTG cleanup level of 250 mg/kg for DRO. Results from the DWW sample were not detected above laboratory limits of quantitation (LOQ). A small excavation was completed at the location of Sample SB2 in early July 2014. Roughly 22 tons of impacted soil were excavated and transported offsite for disposal at Alaska Soil Recycling (ASR). Confirmation soil samples collected from the excavation revealed that DRO impacted soil remained on the southern sidewall in concentrations up to 774 mg/kg. Between July 2014 and April 2015, an additional 38 soil borings were advanced at the site in an effort to delineate soil contamination. Results of the soil boring investigation revealed that contamination remained in the surface and subsurface soils intermittently above ADEC MTG cleanup levels. Levels of contamination in the soil varied across the site; however, based on the results of several soil samples, did not impact the silt layer (as noted above), which was encountered consistently throughout the site. The silt layer was generally encountered around 10 feet bgs.
|
Joshua Barsis |
| 7/15/2015 |
Document, Report, or Work plan Review - other |
ADEC reviewed the Work Plan for Additional Excavation Activities, dated July 15, 2015. Proposed activities include excavating select areas of contamination and collecting soil samples to delineate the horizontal extent. ADEC responded to the work plan via letter on July 15, 2015 and stated that confirmation soil samples from the base of every excavation would be required. |
Joshua Barsis |
| 8/24/2015 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79778 Commercial Property - 900 East Dowling Road. |
Joshua Barsis |
| 8/25/2015 |
Document, Report, or Work plan Review - other |
Reviewed and approved work plan modification received via email on 8-25-2015. |
Joshua Barsis |
| 8/26/2015 |
Site Visit |
Performed site visit to observe test pit and surface contamination removal activities. During test pit activities, a continuous silt layer was observed between 8 and 12 feet below ground surface (bgs). It was noted that Discovery Drilling was also onsite and was performing geotechnical work. Review of boring logs revealed groundwater at 16.5 feet bgs. |
Joshua Barsis |
| 10/9/2015 |
Document, Report, or Work plan Review - other |
Reviewed October 2015 Excavation Report, which detailed the removal of about 210 cubic yards impacted surface material. In addition to the surface excavation, a test pit was advanced to the silt layer so that a sample could be collected. The purpose of the test pit was to confirm that contamination was not migrating through the silt layer to groundwater in the area of greatest contamination. All confirmation soil samples collected from the surface excavations and from the silt layer were below the most stringent ADEC cleanup levels. |
Joshua Barsis |
| 10/21/2015 |
Cleanup Complete Determination Issued |
Petroleum contamination remains in sub-surface soil above MTG cleanup levels; however ADEC has determined there is no unacceptable risk to human health or the environment as long as the contamination is properly managed, subject to the following conditions. 1) Any future change in land use may impact the exposure assumptions cited in this document. If land use and/or ownership changes, these management conditions may not be protective and ADEC may require additional remediation and revised conditions. Therefore the RP shall report to ADEC every 5 years to document land use, or report as soon as RP becomes aware of any change in land ownership and/or use, if earlier. 2) A Notice of Environmental Contamination (deed notice) shall be recorded in the State Recorder’s Office as an institutional control (IC) that identifies the nature and extent of contamination at the property and the conditions that the owners and operators are subject to in accordance with this decision document. 3) Installation of groundwater wells requires ADEC approval. 4) Sub-surface soil contamination is located sporadically across the property. If contamination is encountered in the future or if the soil becomes accessible, the soil must be evaluated and contamination addressed in accordance with an ADEC approved work plan. 5) Benzene contamination remains in the subsurface soils above MTG cleanup levels. If in the future a structure (temporary or permanent) is constructed within 30 feet of the known contamination, ADEC must be contacted and a vapor intrusion (VI) evaluation will likely be required. 6) Any proposal to transport soil or groundwater off-site requires ADEC approval in accordance with 18 AAC 75.325. 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. 7) Movement or use of contaminated material in a manner that results in a violation of 18 AAC 70 water quality standards is prohibited.
|
Joshua Barsis |
| 10/21/2015 |
Institutional Control Record Established |
Institutional Controls established and entered into the database. |
Joshua Barsis |
| 11/6/2015 |
Update or Other Action |
Signed IC Document received. |
Joshua Barsis |
| 9/30/2016 |
Institutional Control Compliance Review |
IC compliance review conducted. Staff changed from Joshus Barsis to IC Unit. IC/Closure Details added. Recorded NEC and signed ICs Agreement Page uploaded. Reminder system set to follow-up in 2020. |
Kristin Thompson |
| 12/1/2016 |
Institutional Control Update |
New construction is being planned on this property. DEC participated in a meeting with BGES Environmental Consulting and the project contractor regarding working around the remaining subsurface soil contamination. The new building will be located more than 30 feet away from the area of subsurface soil contamination so there should be no issues with vapor intrusion into the building. Some asphalt will be removed and then repaved but they should not have to dig into the soil. There will be no trenching required for this project. DEC encouraged the contractors to have a soil management plan in place so that construction activities would not have to be halted if contamination is encountered. |
Evonne Reese |
| 12/21/2016 |
Update or Other Action |
Staff changed from IC Unit back to Joshua Barsis. |
Kristin Thompson |
| 12/21/2016 |
Document, Report, or Work plan Review - other |
Reviewed the document titled Potentially-Contaminated Soil and Groundwater Management Plan, dated for December 2016, and for planned construction activities the Commercial Property - 900 East Dowling Road site. This soil management plan (SMP) outlines the proposed methodology for handling impacted soil or groundwater that may be encountered at the site during the 2017 planned construction activities. |
Joshua Barsis |
