| Action Date |
Action |
Description |
DEC Staff |
| 7/21/2015 |
Site Added to Database |
A new site has been added to the database |
Lisa Griswold |
| 7/22/2015 |
Potentially Responsible Party/State Interest Letter |
PRP sent to Landowner |
Lisa Griswold |
| 10/6/2015 |
Site Characterization Workplan Approved |
ADEC has no objection to the proposed actions in the Work Plan for Site Characterization dated September 29, 2015. The Proposed activities include advancing soil borings on the east, southeast and southwest portions of the property in order to define the lateral and vertical extent of contamination in the Spring of 2016. |
Lisa Griswold |
| 10/28/2015 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79788 name: Commercial Property - 625 W Potter Drive |
Lisa Griswold |
| 5/26/2016 |
Update or Other Action |
Results of the May 2016 Site Characterization reviewed with consultant and RP on this date. 10 bore holes were advanced, with four confirming contaminant concentrations of DRO up to 569 mg/Kg at 0-5 feet bgs; up to 1,530 mg/Kg DRO and benzene up to 0.0396 mg/Kg at 5-7.5 feet bgs; 673 mg/Kg DRO at 7.5-10 feet bgs; and up to 492 mg/Kg DRO at 10-15 feet bgs. Based on these results, additional site characterization is required to delineate the extent of the contamination. |
Lisa Griswold |
| 6/23/2016 |
Site Characterization Workplan Approved |
Additional Site Characterization approved. The proposed activities include advancing soil borings to the south and west sides of previously drilled borings in order to define the lateral and vertical extent of contamination using the procedures outlined in the approved September 29, 2015. ADEC requested that the original work plan be attached to the addendum for reference. |
Lisa Griswold |
| 12/9/2016 |
Site Characterization Workplan Approved |
Addendum for further site characterization work plan emailed on December 8, 2016 conditionally approved on this date. The proposed activities include advancing soil borings to further delineate contamination on site using the procedures outlined in the additional site characterization work plan previously approved on June 23, 2016. The additional site characterization is to be conducted 12/10/2016-12/11/2016. |
Lisa Griswold |
| 1/18/2017 |
Document, Report, or Work plan Review - other |
Additional site characterization report reviewed and approved on this date. Fifteen soil borings were advanced to 15-20 feet below ground surface (bgs) around the western and southern sides of the building. Due to the lack of groundwater encountered by Northern Geotechnical Engineerings, Inc. during the evaluation of the subsurface conditions present down to 41.5 feet bgs, it was proposed that the Method Two, Under 40 inch zone soil cleanup levels for protection of Human Health in 18 AAC 75.341 (c)Table B1 and Method Two Maximum Allowable Concentrations in 18 AAC 75.341 (d) Table B2 be used to evaluate the site. Under these guidelines, only two samples exceeded ADEC cleanup levels: SB-22-2 and SB-22-25 for total Xylenes (up to 190.2 J mg/Kg). ADEC provided the following comments: A test pit or bore hole completed during the site remediation along the western property line between SB-13 and SB-23 with an analytical sample taken at the highest Photoionization Detector (PID) reading would be helpful to consider the site completely characterized.
|
Lisa Griswold |
| 1/18/2017 |
Document, Report, or Work plan Review - other |
Work plan for site remediation reviewed and approved on this date. The work plan proposed excavating, screening, sampling and removing impacted soil around SB-22. The area, marked in area “A” in the additional site characterization report is present from approximately 1.5 feet bgs-5 feet bgs and encompasses approximately 406 square feet. The soil will be screened using heated headspace, sampled per ADEC excavated soil sample collection guide, and the soils that screen above 50 ppmv will be transported to Alaska Soil Recycling for thermal treatment. ADEC approved of this work plan contingent upon the following: The soils should be segregated between “impacted” and “clean” on a liner on site to minimize any cross contamination between impacted and clean soils on site and; The choice of 50 ppmv to delineate the excavated soils between “impacted” or “clean” may or may not be indicative of true contaminant level. Confirmation samples should be taken from the “clean” stockpile in accordance with the ADEC field sampling guidance, and it should be noted that the “clean” soils being used for backfill immediately could contain Xylene levels above ADEC human health cleanup levels.
|
Lisa Griswold |
| 4/10/2017 |
Offsite Soil or Groundwater Disposal Approved |
Approval given to transport 40 cubic yards of soil to ASR for thermal treatment. Soil will be tested for DRO, RRO, GRO, BTEX. Consultant informed ADEC, per ASR's request, the soil will also be tested for VOCs. |
Lisa Griswold |
| 5/16/2017 |
Document, Report, or Work plan Review - other |
ADEC approved of the Report for Site Remediation (Soil Excavation) Activities on this date. The Report detailed work completed on April 8-9, 2017. It included the excavation, sampling and disposal of Xylene impacted soil located around soil boring SB-22; and the sampling of Test Pit (TP-01) along the western edge of the property between SB-13, and SB-23 in order to consider the site fully characterized in accordance with 18 AAC 75.335. The soil excavation activities in April 2017 did not detect contaminants above Human Health levels in Table B1 (Up to 0.491 mg/Kg benzene in SS-004; 4.03 mg/Kg Ethylbenzene in SS-003; 0.048 mg/Kg Toluene in SS-003; and 19.83 mg/Kg Xylenes in SS-003), or Maximum Allowable Concentrations in Table B2 (Up to 1,860 mg/Kg Residual Range Organics (RRO); 782 mg/Kg Diesel Range Organics (DRO) in TP-01). Groundwater has not been encountered on the site during characterization activities, and a 2014 geotechnical report did not encounter groundwater down to 41.5 feet bgs. The site will be evaluated for a cleanup complete determination. |
Lisa Griswold |
| 7/5/2017 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79788 Commercial Property - 625 W Potter Drive. |
Lisa Griswold |
| 8/1/2017 |
Cleanup Complete Determination Issued |
|
Lisa Griswold |
