Site Report: Residence - 6701 North En Dove Road
| Site Name: | Residence - 6701 North En Dove Road |
|---|---|
| Address: | 6701 North En Dove Road, Wasilla, AK 99654 |
| File Number: | 2265.38.038 |
| Hazard ID: | 25648 |
| Status: | Cleanup Complete |
| Staff: | IC Unit, 9074655229 dec.icunit@alaska.gov |
| Latitude: | 61.658130 |
| Longitude: | -149.342417 |
| Horizontal Datum: | WGS84 |
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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
During the performance of a Phase I Environmental Site Assessment, an onsite residential garbage pit was discovered on the western portion of the property at 6701 North En Dove Road. The garbage pit, approximately 48 feet in length, 40 feet in width, and 20 feet in depth, is located to the west of the shop building. The pit had reportedly been excavated to approximately 20 feet below grade and filled with household wastes before being backfilled to grade with the removed soils. Because of the unknown contents of the identified garbage pit, this feature was considered to represent a recognized environmental condition with respect to the subject property. During December of 2010, the garbage pit was investigated through the advancement of three soil boring to evaluate for the potential presence of contamination. Soil sample (SB1) collected from approximately 15 to 20 feet bg from within the garbage pit exhibited an elevated PCE concentration of 0.048 mg/Kg; exceeding the migration to groundwater ADEC cleanup criterion of 0.024 mg/Kg. Four additional soil borings (SB-8 through SB-11) were subsequently advanced within the garbage pit in February of 2011 to evaluate the vertical and lateral extent of the PCE contamination. Soil Samples SB8-4, SB10-4, and SB11-4, collected from a depth range of approximately 15 to 20 feet bg, exhibited a range of PCE concentrations from 0.0311 mg/Kg to 0.044 mg/Kg; all of which exceed the ADEC cleanup criterion. Soil samples collected from depths between 25 and 52 feet bg, exhibited non-detectable concentrations of PCE below the laboratory’s method reporting limits (MRLs) and/or below the ADEC Method 2, migration to groundwater cleanup criterion. Finally, Soil Sample SB9-2, collected from a depth range of approximately 5 to 10 feet bg, exhibited non-detectable concentrations of PCE below the laboratory’s MRLs and the ADEC cleanup criterion. Based on samples taken the contamination appears to be at a depth range between 10 and 25 feet bg. Groundwater was not encountered at a depth 52 feet bg, depth of ground water is unknown. It is not known when and how the release occurred. The garbage pit was being used by the residential owner of the property. The water-supply well used for this residential property is located near the residential house which is more than 400 feet to the northeast of the garbage pit. The proposed plan is to leave the contamination in place because it appears to be defined to a limited area at a depth of 15 to 20 feet bg as described above. The objective for this site is to achieve "Cleanup Complete with Institutional Controls".
Action Information
| Action Date | Action | Description | DEC Staff |
|---|---|---|---|
| 4/15/2011 | Spill Transferred from Prevention Preparedness and Response Program | Spill transferred by PERP staff Mark Sielaff. Spill no. 10239936401; spill date = 12/30/10; substance = tetrachloroethene, chromium, arsenic; quantity = unknown. | Mitzi Read |
| 4/22/2011 | Site Added to Database | A new site has been added to the database | Mitzi Read |
| 4/25/2011 | Exposure Tracking Model Ranking | Initial ranking with ETM completed for source area id: 79080 name: Residential Garbage Pit | Mitzi Read |
| 8/4/2011 | Document, Report, or Work plan Review - other | Reviewed Limited Phase II ESA Workplan, 6701 North En Dove Road Wasilla, Alaska. Previous sampling conducted during initial Phase II investigations in December 2010 and February 2011 found PCE up to 0.048 mg/kg at 15-20 feet bgs in an area formerly used as a garbage pit. Each of the four samples collected from this interval in the garbage pit contained PCE above the Method Two migration to groundwater cleanup level of 0.024 mg/kg. Deeper and shallower soils reportedly did not contain detectable concentrations of PCE. Additional investigation activities proposed in this work plan include the advancement of four soil borings around the perimeter of the garbage pit, approximately 10 feet from the edge of the pit. Soil samples will be collected from the same interval where PCE was detected in previous samples, 15-20 feet bgs, and also from 20-25 feet and analyzed for VOCs. The deeper samples will only be analyzed if PCE is detected in shallower samples, or if it is anticipated that the deeper samples would not meet hold times prior to receipt of data from the shallower samples. Soil cuttings will be stored on site until characterized at which time a disposal method will be proposed to ADEC for approval. | Bill O'Connell |
| 10/12/2011 | Document, Report, or Work plan Review - other | DEC staff reviewed BGES Inc.'s "2011 Site Characterization Report", dated September 2011. In the report, BGES documented the results of the advancement of four soil borings around the perimeter of the trash pit. The borings were advanced to depths of 25 feet below ground surface north, south, east, and west of the trash pit. No contaminants of concern were detected in soil samples collected from depths ranging from 16 to 25 feet below ground surface. | Todd Blessing |
| 10/28/2011 | Cleanup Complete Determination Issued | PCE contamination above established default cleanup levels in soil remains on-site at 15 to 20 feet below ground surface within a disposal pit that is located on the southwest corner of the property. The disposal pit is roughly 48 feet in length by 40 feet in width by 20 feet deep. Groundwater is not believed to be impacted from past activities at the site including from two drain pipes and from the disposal of household waste into the garbage pit. ADEC has determined there is no unacceptable risk to human health or the environment since current site exposure pathways that are complete have been determined to be minimis. Therefore, this site was issued a Cleanup Complete- ICs determination | Todd Blessing |
| 10/28/2011 | Institutional Control Record Established | Institutional Controls established and entered into the database. | Todd Blessing |
| 11/10/2011 | Update or Other Action | DEC issued a revised Record of Decision and NEC that was orginally issued on October 28th. The revised documents addressed Kate Dernocoeur's concerns that she should be referred to as a personal representative to the estate of Mike Downs. | Todd Blessing |
| 11/14/2011 | Update or Other Action | DEC staff recieved confirmation that the floor drains were decommissioned. On November 10, 2011, BGES representatives utilized a gravel and concrete mixture to backfill the drain pipe to approximately 1 foot below grade. Then the remaining annular space was filled with concrete to the surface. | Todd Blessing |
| 11/28/2022 | Institutional Control Update | Initial review conducted. Issue the first IC reminder letter and check on the status of the floor drain that was on site at the time of closure. It is believed that the 2011 Notice of Environmental Contamination was never filed on the property deed. | Evonne Reese |
| 8/10/2023 | Institutional Control Update | Correction to the 2022 entry. DEC recieved confirmation that the floor drains were decommissioned in 2011. The planned 2021 IC reminder letter was not issued due to difficulties finding the new landowner. The property may have been subdivided. | Evonne Reese |
| 8/11/2023 | Institutional Control Compliance Review | An IC reminder letter was issued on this date to the landowners of the property where the former garbage pit is located. After doing a property ownership search and checking with the Matsu Property Assessor's office, I found this is adjacent property to the 6701 N. En Dove Road property where the former auto shop and injection wells are located. At this point is is unknown if the property has been subdivided since the 2011 site closure. | Evonne Reese |
| 10/6/2023 | Institutional Control Record Removed | Institutional controls have been removed from this site record and the status is now Cleanup Complete. At the time of closure, the highest detected concentration for remaining PCE in the soil was 0.048 mg/kg and the cleanup level was 0.005 mg/kg. In 2016, regulatory cleanup levels for PCE were updated and the cleanup level for PCE in soil was changed to 0.19 mg/kg. This means the remaining PCE contamination in the soil on this property now meets the current cleanup levels. The highest PCE concentration is below approved migration to groundwater cleanup levels. A decision document letter was issued to the landowner on this date. | Evonne Reese |
Contaminant Information
| Name | Level Description | Media | Comments |
|---|---|---|---|
| Tetrachloroethene | < Method 2 Most Stringent | Soil | PCE levels on this property are below the cleanup levels. |
Control Type
| Type | Details |
|---|---|
| No ICs Required |
Requirements
| 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) |
No associated sites were found.