| Action Date |
Action |
Description |
DEC Staff |
| 8/23/2011 |
Site Added to Database |
A new site has been added to the database |
Alyce Hughey |
| 8/23/2011 |
Leaking Underground Storage Tank Release Confirmed - Petroleum |
LUST site created in CSP database for source area Underground Storage Tanks, 79142 |
Alyce Hughey |
| 8/23/2011 |
Leaking Underground Storage Tank Cleanup Initiated - Petroleum |
Approximately 30 cubic yards of contaminated soil was excavated when a release was detected during routine tank maintenance on August 15, 2011, |
Alyce Hughey |
| 8/23/2011 |
Exposure Tracking Model On Hold |
Exposure Tracking on hold until final release investigation and/or corrective action report is received and reviewed. |
Alyce Hughey |
| 8/23/2011 |
Offsite Soil or Groundwater Disposal Approved |
Approved the transport of approximately 30 cubic yards of petroleum contaminated soil to Alaska Soil Recycling (ASR) for thermal remediation and disposal. Following thermal remediation ASR will need to test the treated soils using the appropriate laboratory methods for BTEX, GRO, and DRO. |
Paul Horwath |
| 10/20/2011 |
Exposure Tracking Model Ranking |
Initial ranking with ETM completed for source area id: 79142 name: Underground Storage Tanks |
Alyce Hughey |
| 10/21/2011 |
Document, Report, or Work plan Review - other |
Reviewed the August 2011 Release Investigation Report, dated October 2011, from MWH. The Release Investigation was performed on August 15th through 17th, 2011 to determine the nature and extent of the fuel release. The contaminated soil was removed from beneath the fill ports and approximately 6 feet below ground surface adjacent to tank #5 (unleaded gasoline), and approximately 3 feet below ground surface beneath Tank #4 (diesel) fill port and stockpiled on site. It was determined that further excavation was not feasible due to the continued use of the fuel tanks and systems. The amount of release was estimated at approximately 10 to 15-gallons. The 58.25 tons of stockpiled soil was transported to Alaska Soil Recycling on August 24, 2011 for thermal remediation and disposal. Horizontal soil vapor extraction piping was installed along the north and south sides of Tank #5 for a future treatment option for the remaining contaminated soil. Confirmation soil samples taken at 6 feet below ground surface from the North and South sides of Tank #5 detected DRO at 275 mg/kg, GRO at 794 and 994 mg/kg, Benzene at 0.159 and 0.293 mg/kg, Toluene at 16.5 and 21.4 m/kg, Ethylbenzene at 24.6 and 25.3 mg/kg, and Xylenes at 187 at 193 mg/kg. |
Alyce Hughey |
| 12/1/2011 |
Meeting or Teleconference Held |
Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012. |
Alyce Hughey |
| 12/1/2011 |
Meeting or Teleconference Held |
Staff attended the annual environmental planning meeting with Tesoro and MWH to discuss the workplans for 2012. |
Paul Horwath |
| 12/28/2011 |
Document, Report, or Work plan Review - other |
Reviewed the October 2011 Drinking Water Sample Report, dated November 11, 2011, from MWH. On October 21, 2011 a drinking water sample was taken from a pre-filter spigot in the utility room to ensure that the groundwater aquifer that supplied water to the retail market was not impacted by the petroleum release from the underground storage tanks. The analytical results did not detect any of the analytes tested for. |
Alyce Hughey |
| 6/6/2012 |
Meeting or Teleconference Held |
Staff attended the mid-year planning meeting at the ADEC office in Soldotna to discuss the proposed additional assessment activities to be performed in 2012 at Tesoro Northstore #78. |
Alyce Hughey |
| 8/20/2012 |
Offsite Soil or Groundwater Disposal Approved |
Approved the transport of two drums of petroleum contaminated soil to Alaska Soil Recycling in Anchorage. The petroleum product is reported to be automotive gasoline and the post treatment analysis required to be performed on these soils are GRO and BTEX. |
Paul Horwath |
| 11/14/2012 |
Meeting or Teleconference Held |
Paul Horwath and Alyce Hughey attended the annual planning meeting at MWH office in Anchorage to discuss the Corrective Action Work Plan for 2013. |
Alyce Hughey |
| 1/3/2013 |
Underground Storage Tank Site Characterization or Assessment |
Reviewed the June and July 2012 Release Investigation Report, dated November 2012, prepared by MWH. On June 20 and 21, 2012 three soil borings made into monitoring wells and a Soil Vapor Extraction pilot study was conducted. Benzene soil contamination was encountered in one soil boring at 0.0254 mg/kg at 17 feet below ground surface. The soil vapor extraction pilot test conducted on June 20, had minimal hydrocarbons being detected in the systems exhaust. Groundwater samples collected on July 18, detected benzene in MW-1 at 0.0164 mg/L. A follow-up sample was collected on September 5, 2012 with benzene in MW-1 at 0.000605 mg/L. An on-site drinking water well was sampled on September 5, 2012 with all analytes not being detected. |
Alyce Hughey |
| 6/4/2013 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79142 Underground Storage Tanks. |
Paul Horwath |
| 6/26/2013 |
Document, Report, or Work plan Review - other |
Reviewed the April 2013 Monitoring Event Report, dated June 2013, from MWH. On April 29, 2013 three groundwater monitoring wells MW-1 through MW-3 were sampled after purging three well volumes prior to sample collection. The on-site drinking water was also sampled. All sample results were non-detect for all analytes. Groundwater was flowing towards the west with a bearing of 275 degrees at a gradient of 0.0122. The depth to groundwater was 39.00 to 41.02 feet. |
Alyce Hughey |
| 6/27/2013 |
Exposure Tracking Model Ranking |
A new updated ranking with ETM has been completed for source area 79142 Underground Storage Tanks. |
Paul Horwath |
| 7/30/2013 |
Meeting or Teleconference Held |
Staff attended the mid-year planning meeting at the ADEC office in Soldotna to discuss the location of the on-site drinking water well and site closure. |
Alyce Hughey |
| 8/5/2013 |
Cleanup Complete Determination Issued |
Corrective Action Complete Determination Issued. The most current soil sample analytical data reported BTEX, GRO, and DRO contamination exceeding the applicable soil cleanup levels, in the area of the underground storage tanks, within the AREA OF CONCERN identified on FIGURE 1, SITE PLAN WITH AREA OF CONCERN (see Attachment A). Any proposal to excavate, transport, move, treat, and/or dispose of residual contaminated soil at this “site” requires prior ADEC approval. Groundwater concentrations have tested either below the groundwater cleanup levels, or non-detected, for the last two groundwater sampling events. There are no known drinking water wells located immediately down-gradient of the site, and the drinking water well that serves the Tesoro station is located approximately 250 feet from the UST system, and is up-gradient and cross-gradient of the UST system. The onsite drinking water supply well produces water from a deeper groundwater aquifer that is not hydrogeologically connected to the shallow ground water table encountered beneath the UST system. All groundwater monitoring wells, treatment wells, and subsurface treatment piping associated with this project must now be properly decommissioned in accordance with ADEC’s November 2011 Monitoring Well Guidance. |
Paul Horwath |
| 9/10/2013 |
Long Term Monitoring Complete |
Issued approval of a work plan to decommission the three groundwater monitoring wells, and the subsurface SVE treatment piping. |
Paul Horwath |
| 11/22/2013 |
Document, Report, or Work plan Review - other |
Reviewed the September 2013 Monitoring Wells Decommissioning Report, dated October 25, 2013, prepared by MWH. On September 16, 2013 the three groundwater monitoring wells (MW-1, MW-2 and MW-3) and horizontal SVE remediation piping were decommissioned. The decommissioning was performed according to ADEC’s Monitoring Well Guidance, dated September 2013. |
Alyce Hughey |
| 12/3/2013 |
Meeting or Teleconference Held |
Paul Horwath and Alyce Hughey attended the annual planning meeting at MWH office in Anchorage to discuss the decommissioning work performed at the site in 2013. |
Alyce Hughey |
