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Site Report: Chevron - #90430

Site Name: Chevron - #90430
Address: 6470 Debarr Rd., Anchorage, AK 99504
File Number: 2100.26.010
Hazard ID: 23615
Status: Active
Staff: Rebekah Reams, 9074512144 rebekah.reams@alaska.gov
Latitude: 61.209200
Longitude: -149.760130
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.

Problems/Comments

Operated as a Chevron gas station from 1969 until 2000. Soil and groundwater samples collected in 1992 identified soil and groundwater contamination above cleanup levels. Historically the depth to groundwater below the ground surface has ranged from 7 to 23 feet below ground surface in the site monitoring wells. A water well search conducted in 1992 identified some active drinking water wells in the area. Several monitoring wells were installed in 1992. Additional monitoring wells were installed in 1994, 1998, 2000, 2002, and 2006 to help define the extent of the groundwater contamination at the site. In 1995 seven underground storage tanks (UST's) were removed and replacement tanks and piping were installed. An air sparging/soil vapor extraction remediation system was installed in 1995, upgraded in 2006, operated until 2013, and was decommissioned in 2014 in preparation for site redevelopment planned in 2015. Up to 4 feet of gasoline product found in two monitoring wells in 1996, and measureable product existed until 2003. MTBE groundwater contamination was identified in areas of the site in 1999, and still remains in one monitoring well (MW-5R) on the property. The closest drinking water wells were sampled and have tested free of petroleum contamination. In 2000 the service station was demolished and the remaining UST's and their associated piping were removed. Based on historic soil and groundwater sampling data, soil and groundwater contamination appears to have extended in the past off-property to the north, east, and west. Based on current groundwater sampling data it appears that groundwater contamination no longer extends off-property to the north and west. Groundwater contamination may extend off-property to the east into Summit Drive. Between May 31, 2015 and June 3, 2015 pulverized gypsum (calcium sulfate) was applied on the ground surface over a 21,334 square foot area of the site and 27,000 gallons of water was applied to help dissolve the sulfate to transport it into the underlying soil and groundwater. On September 26, 2017 six soil gas probes were installed and sampled. These probes were installed on August 14-15, 2017 and they were all installed to a depth of 6.5 feet below ground surface. Three are located in the area of the proposed store building and three more are located on the east side of the strip mall building located on the property to the east of the gas station property.

Action Information

Action Date Action Description DEC Staff
9/4/1992 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 77950 Former Staff
9/4/1992 Site Added to Database Former Staff
9/5/1992 Leaking Underground Storage Tank Cleanup Initiated - Petroleum LCAU Date changed DB conversion Former Staff
10/21/1992 Update or Other Action Notice of Release letter sent. Former Staff
1/22/1993 Release Investigation Water well survey reveals several drinking water wells within 1/4 mile. Requested at a minimum that the nearest downgradient drinking water wells be sampled. Former Staff
10/1/1994 Leaking Underground Storage Tank Corrective Action Underway Performed a Corrective Action Plan Review. Former Staff
5/22/1995 Document, Report, or Work plan Review - other Reviewed a corrective action plan addendum. Air sparging/soil vapor extraction system is to be installed later in 1995. Former Staff
11/22/1995 Underground Storage Tank Site Characterization or Assessment Reviewed a phase 1 site assessment report for the removal of USTs. Former Staff
12/22/2000 Update or Other Action Sent email to Roger Hoffmore (SECOR) inquiring as to status of remediation system. Robert Weimer & I made a site visit to observe tank removal during December, air sparging/soil vapor extraction system not operational at the time of our site visit. Linda Nuechterlein
1/22/2001 Update or Other Action Didn't receive response to my email to SECOR. Sent follow-up letter to Bob Cochran (Chevron) as to status of remediation system. Also reminded Chevron that prior approval required if the remediation system is to be shut-down. Linda Nuechterlein
1/30/2001 Update or Other Action ADEC annual meeting with Chevron representatives Bob Cochran & Roger Hoffmore. Reviewed sites & establish goals for 2001. Linda Nuechterlein
4/2/2001 Update or Other Action Closure site assessment report for removal of the UST systems on December 2000 was submitted. Additional submittals should have been received. See 4/16/01 entry. Linda Nuechterlein
4/16/2001 Update or Other Action ADEC letter sent to Chevron requesting a corrective action plan and analytical results for domestic supply well sampling. See letter for details. Work plan submittal due by April 30, 2001. Linda Nuechterlein
5/4/2001 Update or Other Action Discussed SECOR draft drawing of the air sparging/ soil vapor extraction system with Scott Gable. Requested that he respond to my email comments and submit completed air sparging and soil vapor extraction checklists for this and future work plans. Linda Nuechterlein
7/1/2001 Document, Report, or Work plan Review - other Received semi-annual groundwater monitoring report dated June 2001 and remedial system report dated July 2001. Linda Nuechterlein
6/19/2003 Offsite Soil or Groundwater Disposal Approved Approved soils to ASR for thermal treatment Robert Weimer
6/10/2004 Document, Report, or Work plan Review - other Reviewed quarterly remediation system report. Soil vapor extraction system operated 75% of the time. 24.2 pounds of BTEX removed in this quarter. Robert Weimer
8/9/2004 Document, Report, or Work plan Review - other June 9, 2004 groundwater monitoring. Up to 370 mg/l GRO, 13,000 ug/l benzene, and 36,000 ug/l MTBE. Contamination levels appear to be generally stable. Robert Weimer
8/23/2004 Document, Report, or Work plan Review - other Second quarter 2004 remediation system status report. Soil vapor extraction system operated 57% of the time, it removed 12.7 pounds of BTEX during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells. Robert Weimer
12/8/2004 Document, Report, or Work plan Review - other September 28, 2004 groundwater monitoring. Up to 130 mg/l GRO, 21,000 ug/l benzene, and 17,000 ug/l MTBE. Contamination levels appear to be generally stable. Robert Weimer
12/10/2004 Document, Report, or Work plan Review - other Third quarter 2004 remediation system status report. Soil vapor extraction system operated 100% of the time, it removed 57.7 pounds of BTEX during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2005. To date, 1003 pounds of GRO and 380 pounds of BTEX have been removed by the remediation system. Robert Weimer
2/15/2005 Document, Report, or Work plan Review - other Fourth quarter 2004 remediation system status report. Soil vapor extraction system operated 96% of the time, it removed 48.8 pounds of BTEX and 5.3 pounds of GRO during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2005. To date, 1,008 pounds of GRO and 429 pounds of BTEX have been removed by the remediation system. Robert Weimer
5/31/2005 Document, Report, or Work plan Review - other First quarter 2005 remediation system status report. Soil vapor extraction system operated 97% of the time, it removed 66.6 pounds of BTEX and 7.3 pounds of GRO during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2005. To date, 1,016 pounds of GRO and 496 pounds of BTEX have been removed by the remediation system. Robert Weimer
8/9/2005 Document, Report, or Work plan Review - other May 15, 2005 groundwater monitoring. Up to 430 mg/l GRO, 19,000 ug/l benzene, and 670 ug/l MTBE. Contamination levels appear to be generally stable. Groundwater flow direction is to the west. Robert Weimer
8/17/2005 Document, Report, or Work plan Review - other Second quarter 2005 remediation system status report. Soil vapor extraction system operated 71% of the time, it removed 50.2 pounds of BTEX and 6.1 pounds of GRO during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2006. To date, 1022 pounds of GRO and 552 pounds of BTEX have been removed by the remediation system. Robert Weimer
11/28/2005 Document, Report, or Work plan Review - other Third quarter 2005 remediation system status report. Soil vapor extraction system operated 76% of the time, it removed 50.5 pounds of BTEX and 7.3 pounds of GRO during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2006. To date, 1029 pounds of GRO and 602 pounds of BTEX have been removed by the remediation system. Robert Weimer
12/19/2005 Document, Report, or Work plan Review - other September 26, 2005 groundwater monitoring. Up to 1.7 mg/l GRO, 340 ug/l benzene, and 4 ug/l MTBE. Contamination levels appear to be decreasing. Groundwater flow direction is to the southwest. Depth to groundwater is 8 to 18 feet below ground surface. Robert Weimer
2/3/2006 Document, Report, or Work plan Review - other Fourth quarter 2005 remediation system status report. Soil vapor extraction system operated 82% of the time, it removed 41.9 pounds of BTEX and 4.6 pounds of GRO during this quarter. Air sparging system currently off-line waiting the installation of additional air sparge wells in 2006. To date, 1034 pounds of GRO and 644 pounds of BTEX have been removed by the remediation system. Robert Weimer
2/9/2006 Meeting or Teleconference Held Meeting with Chevron to discuss future site work. They are to sample the two highest contaminated wells for EDB and 1,2-DCA in 2006. Approved suspending operation of remediation system until remediation system upgrade in summer of 2006. Robert Weimer
6/8/2006 Update or Other Action Update from Chevron's consultant. The corrective action work plan should be submitted within 2 weeks. Robert Weimer
7/26/2006 Document, Report, or Work plan Review - other Conditional approval of revised July 18, 2006 remedial system upgrade work plan. The plan calls for the installation of two additional soil vapor extraction wells, 27 airsparge wells, one monitoring well (in the former 2000 tank area), and a soil boring at the north dispenser island location. Robert Weimer
8/9/2006 Site Visit Site visit to observe the installation of air sparge wells. Robert Weimer
8/22/2006 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of purge water and disposal of spent activated carbon. Robert Weimer
9/14/2006 Offsite Soil or Groundwater Disposal Approved ADEC approves the thermal treatment of 12 cubic yards of contaminated soil. Robert Weimer
10/2/2006 Document, Report, or Work plan Review - other May 12, 2006 groundwater monitoring. Up to 97 mg/l GRO, 9,800 ug/l benzene, and 3,600 ug/l MTBE. Contamination levels appear to be increasing seasonally (higher concentrations in the summer). Groundwater flow direction is to the west by southwest. Depth to groundwater is 9 to 18 feet below ground surface. Robert Weimer
10/24/2006 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of purge water. Robert Weimer
11/9/2006 Document, Report, or Work plan Review - other First quarter 2006 Remediation System Status Report. System was operational about 33% of the time this quarter. The Air Sparge/Soil Vapor Extraction system is currently off due to electrical problems and is scheduled to restart in 2006. A work plan to upgrade the system is to be submitted in the future. Robert Weimer
12/1/2006 Document, Report, or Work plan Review - other Second quarter 2006 Remediation System Status Report. System was not operational this quarter. The Air Sparge/Soil Vapor Extraction system is currently off due to electrical problems and is scheduled to restart in 2006. System upgrade drilling and trenching is scheduled for August 2006. Robert Weimer
1/8/2007 Document, Report, or Work plan Review - other Remedial System Upgrade Report. Three soil vapor extraction wells, 23 air sparge wells, and 6 groundwater monitoring wells were installed in the summer of 2006. These new remediation wells and the existing soil vapor extraction wells were hooked up to the upgraded treatment shed. The new system will be restarted soon. Up to 2000 mg/kg GRO and 16 mg/kg benzene found in the soil samples collected during the system upgrade. Robert Weimer
4/2/2007 Meeting or Teleconference Held Meeting with RP to discuss site. They are to continue with semi-annual monitoring and sampling. Approved suspending sampling in monitoring well MW-12 and reduce monitoring well MW-17 to annual. Robert Weimer
4/17/2007 Document, Report, or Work plan Review - other Third quarter 2006 Remediation System Status Report. System was not operational this quarter. The Air Sparge/Soil Vapor Extraction system is currently off due to electrical problems and is scheduled to restart in 2006. System upgrade drilling and trenching is scheduled for August 2006. Robert Weimer
5/25/2007 Document, Report, or Work plan Review - other Fourth quarter 2006 Remediation System Status Report. System was not operational this quarter. The Air Sparge/Soil Vapor Extraction system was upgraded and restarted in February 2007. Robert Weimer
7/2/2007 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of two drums of contaminated purge water. Robert Weimer
10/4/2007 Document, Report, or Work plan Review - other May 24, 2007 groundwater monitoring. Up to 420 mg/l GRO, 76,00 ug/l benzene, and 7,700 ug/l MTBE. 1,2-DCA and EDB were non detect. Contamination levels appear to be increasing seasonally (higher concentrations in the summer). Groundwater flow direction is to the west. Depth to groundwater is 8.9 to 17.6 feet below ground surface. Robert Weimer
10/9/2007 Document, Report, or Work plan Review - other First quarter 2007 Remediation System Status Report. The upgraded system began operation this quarter in late February 2007. The system was operated for 31 days the quarter and removed approximately 73 pounds of GRO. Robert Weimer
10/15/2007 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of two drums of contaminated purge water. Robert Weimer
3/5/2008 Update or Other Action Meeting with Chevron and their consultants. Chevron to conduct and indoor air evaluation for this site. The air sparge/soil vapor extraction will be repaired soon. Robert Weimer
3/25/2008 Exposure Tracking Model Ranking Site ranked on the new Exposure Tracking Model (ETM). The ETM is a new site ranking system that looks at, based on available data, the potential exposure pathways for the contamination remaining at the site. Robert Weimer
4/7/2008 Document, Report, or Work plan Review - other Third quarter 2007 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 69% of this quarter and removed approximately 3.5 pounds of GRO. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system is currently pulsing 4 hours a day per bank of wells. Robert Weimer
5/12/2008 Document, Report, or Work plan Review - other September 20, 2007 groundwater monitoring. Up to 180 mg/l GRO, 10000 ug/l benzene, and 12000 ug/l MTBE. 1,2-DCA and EDB were non detect. Contamination levels appear to be increasing. Groundwater flow direction is to the west. Depth to groundwater is 9.49 to 19.19 feet below ground surface. Robert Weimer
8/26/2008 Document, Report, or Work plan Review - other Fourth quarter 2007 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 93% of this quarter and removed approximately 21 pounds of GRO. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system is currently pulsing 4 hours a day per bank of wells. Robert Weimer
8/27/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves the thermal treatment of 5 drums of contaminated soil. Robert Weimer
9/30/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of purge water. Robert Weimer
11/24/2008 Document, Report, or Work plan Review - other First quarter 2008 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 55% of this quarter and removed approximately 3.4 pounds of GRO. Approximately 1054 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system was down from October 31, 2007 to March 21, 2008 for repairs. Robert Weimer
11/24/2008 Document, Report, or Work plan Review - other May 20, 2008 groundwater monitoring. Up to 120 mg/l GRO, 770 ug/l benzene, and 940 ug/l MTBE. 1,2-DCA and EDB were non detect. Contamination levels increased in 1 of the 11 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 8.02 to 16.8 feet below ground surface. Robert Weimer
12/9/2008 Document, Report, or Work plan Review - other Second quarter 2008 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 97% of this quarter and removed approximately 113 pounds of GRO. Approximately 1167 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system was down from October 31, 2007 to April 8, 2008 and again May 13, 2008 to May 18, 2008 for repairs. Robert Weimer
2/25/2009 Meeting or Teleconference Held Meeting with Chevron and their consultants. Chevron to conduct and indoor air evaluation for this site. The air sparge/soil vapor extraction will be repaired again in 2009. Robert Weimer
3/24/2009 Document, Report, or Work plan Review - other Third quarter 2008 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 82% of this quarter and removed approximately 11 pounds of GRO. Approximately 1177 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system was down from October 31, 2007 to April 8, 2008 and again May 13, 2008 to May 18, 2008 for repairs. Robert Weimer
3/31/2009 Update or Other Action ADEC approves request to redevelop sedimented air sparge wells and treat contaminated water at Emerald. Robert Weimer
4/6/2009 Site Characterization Report Approved September 13, 2008 groundwater monitoring. Up to 120 mg/l GRO, 27,000 ug/l benzene, and 1600 ug/l MTBE (470 ug/l cleanup level). 1,2-DCA and EDB were non detect. Contamination levels increased in 5 of the 12 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 10.56 to 18.85 feet below ground surface. Robert Weimer
4/29/2009 Document, Report, or Work plan Review - other Fourth quarter 2008 Remediation System Status Report. The upgraded system began operation in late February 2007. The system was operated 97% of this quarter and removed approximately 9 pounds of GRO. Approximately 1186 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system was down from October 31, 2007 to April 8, 2008 and again May 13, 2008 to May 18, 2008 for repairs. Robert Weimer
6/9/2009 Update or Other Action ADEC approves treatment of three drums of contaminated purge water. Robert Weimer
8/4/2009 Document, Report, or Work plan Review - other First quarter 2009 Remediation System Status Report. The upgraded system began operation in late February 2007. The SVE system was operated 72% of this quarter and removed approximately 910.3pounds of GRO. Approximately 1197 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. The air sparge system was down for repairs this quarter. Robert Weimer
8/20/2009 Site Characterization Report Approved May 21, 2009 groundwater monitoring. Up to 100 mg/l GRO, 6,100 ug/l benzene, and 3600 ug/l MTBE (470 ug/l cleanup level). 1,2-DCA and EDB were non detect. Contamination levels increased in 6 of the 12 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 9.14 to 18.75 feet below ground surface. Robert Weimer
8/26/2009 Document, Report, or Work plan Review - other Second quarter 2009 Remediation System Status Report. The upgraded system began operation in late February 2007. The SVE system was operated 91% of this quarter and removed approximately 4 pounds of GRO. Approximately 1201 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. The air sparge system was restarted on June 2, 2009. Robert Weimer
9/9/2009 Document, Report, or Work plan Review - other ADEC approves suspending the sampling of monitoring wells MW-8 and MW-15. Robert Weimer
2/16/2010 Document, Report, or Work plan Review - other September 15, 2009 groundwater monitoring. Up to 87 mg/l GRO, and 9,200 ug/l benzene. 1,2-DCA and EDB were non detect. Contamination levels increased in 1 of the 12 monitoring wells sampled. Groundwater flow direction is to the west by northwest. Depth to groundwater is 10.71 to 19.76 feet below ground surface. Robert Weimer
3/11/2010 Meeting or Teleconference Held Meeting with Chevron and their consultants on 3/10/10. MW3 & MW7 are to be sampled for PAH the next monitoring event. Chevron will continue to operate the AS/SVE system. We discussed that groundwater samples for volatiles should not be collected with bailers or peristaltic pumps due to the loss of volatiles, Chevron is to provide a workplan specifying how groundwater samples will be collected in the future. Robert Weimer
4/8/2010 Document, Report, or Work plan Review - other DEC review of Site Vapor Intrusion Evaluation report for this site. The report concluded that this site does not have a potential for vapor intrusion based on structures being more than 30 feet away from the remaining soil and groundwater contamination at this site. Robert Weimer
4/9/2010 Update or Other Action ADEC approves suspending, until further notice, the sampling of monitoring wells MW-9 and MW-13. ADEC requests that monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, MW-16, and MW-17 continue to be sampled for GRO and BTEX on a semi-annual basis. ADEC is also requesting that monitoring wells MW-5R, MW-7, and MW-10 be sampled for MTBE on a semi-annual basis, and monitoring wells MW-11 and MW-16 be sampled for MTBE on an annual basis. Robert Weimer
5/20/2010 Update or Other Action Approved, until further notice, no-purge groundwater sampling at this site. Robert Weimer
6/18/2010 Site Visit Site visit to the former gas station. The consultants never showed up to collect groundwater samples as per arrangement. Observed MW locations and site conditions and left site without any sample collection observations. Brenton Porter
10/5/2010 Document, Report, or Work plan Review - other ADEC approves transport of contaminated purge water to the 15th & C secure area for temporary storage. Robert Weimer
10/22/2010 Document, Report, or Work plan Review - other ADEC conditionally approves the October 12, 2010 “Supplemental Site Assessment and Pilot Test Workplan” is approved under the conditions that a complete copy of the field notes be included in the report of the investigation results, that the site work be conducted in accordance with the DEC’s Draft May 2010 Field Sampling Guidance, and the analysis for PAHs be done by method 8270C or 8270D. The plan proposes to drill and sample 10 soil borings to check current contamination levels at areas of the site and to install 2 deeper air sparge wells and conduct a pilot test on those wells. Robert Weimer
10/27/2010 Site Visit At the request of the project manager a site inspection was conducted to oversee field screening and collection of soil samples. Individuals on site included CRA staff members, Brian Duggan, Susan Lear and Nichole Taylor and Brent Porter from the ADEC. Brenton Porter
11/9/2010 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of 1 drum of contaminated purge water. Robert Weimer
11/30/2010 Offsite Soil or Groundwater Disposal Approved ADEC approves thermal treatment of 4 drums and two super sacks of contaminated soil generated during the October 2010 release investigation work. Robert Weimer
3/14/2011 Site Characterization Report Approved June 22, 2010 groundwater monitoring. Up to 23 mg/l GRO, 0.2 mg/l MTBE, and 1,800 ug/l benzene. Contamination levels increased in 1 of the 8 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 10.44 to 18.76 feet below ground surface. Robert Weimer
4/15/2011 Site Characterization Report Approved October 3, 2010 groundwater monitoring. Up to 23 mg/l GRO, 0.061 mg/l MTBE, and 2,600 ug/l benzene. Contamination levels increased in 4 of the 7 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 10.05 to 18.73 feet below ground surface. Robert Weimer
11/9/2011 Document, Report, or Work plan Review - other Third/Fourth quarter 2009 Remediation System Status Report. The upgraded system began operation in late February 2007. The SVE system was not operated from January 2009 through May 2009 because of ice in the lines and broken pipes. It was restarted on June 2, 2009. The system operated 100% in the third quarter and 93% in the fouth quarter, and removed approximately 14.3 pounds of GRO. Approximately 1215 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Robert Weimer
11/22/2011 Document, Report, or Work plan Review - other ADEC approves treatment of drums of contaminated purge water. Robert Weimer
11/22/2011 Document, Report, or Work plan Review - other Third/Fourth quarter 2010 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated 64% in the third and fouth quarter, and removed approximately 12.4 pounds of GRO. Approximately 1244 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Robert Weimer
11/28/2011 Document, Report, or Work plan Review - other October 2010 drilling and sampling of 10 soil borings to check current contamination levels at areas of the site and to install 2 deeper air sparge wells and conduct a pilot test on those wells. Up to 1,100 mg/kg GRO and 12 mg/kg benzene in the soil samples collected. The highest concentrations were at 17 feet below ground surface near the soil/water interface. MTBE and PAH samples were below cleanup levels. Robert Weimer
12/6/2011 Document, Report, or Work plan Review - other ADEC approves the storage over the winter of 1 drum of contaminated purgewater at the 1441 C Street secure yard. Robert Weimer
2/1/2012 Document, Report, or Work plan Review - other April 18, 2011 groundwater monitoring. Up to 4.7 mg/l GRO, 0.14 mg/l MTBE, 0.0209 mg/l lead, and 400 ug/l benzene. Contamination levels increased in 1 of the 9 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 8.61 to 19.87 feet below ground surface. Robert Weimer
3/7/2012 Meeting or Teleconference Held Meeting with Chevron and their consultants on 2/28/12. Chevron plans to continue operate the AS/SVE system, connect MW-3 & MW-4R seasonally, evaluate effectiveness of the new AS wells, and submit conceptual site model. They are to continue semi-annual groundwater monitoring. Robert Weimer
8/17/2012 Offsite Soil or Groundwater Disposal Approved ADEC approves offsite treatment of 1 drum of contaminated development water and 1 drum of contaminated purge water. Robert Weimer
8/24/2012 Document, Report, or Work plan Review - other First/Second quarter 2011 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated 67% in the first and second quarter, and removed approximately 10.8 pounds of GRO. Approximately 1,255 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Some ves lines were found to be frozen or to contain excess water. Robert Weimer
9/17/2012 Offsite Soil or Groundwater Disposal Approved ADEC approves offsite treatment of 1 drum of contaminated purge water. Robert Weimer
10/29/2012 Document, Report, or Work plan Review - other Third/Fourth quarter 2011 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated 61% in the third and fourth quarter, and removed approximately 60.1 pounds of GRO. Approximately 1,460 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Some ves lines were found to be frozen or to contain excess water. Robert Weimer
1/9/2013 Document, Report, or Work plan Review - other October 5, 2011 groundwater monitoring. Up to 64.0 mg/l GRO, 0.38 mg/l MTBE, 0.0064 mg/l lead, and 11,000 ug/l benzene. Contamination levels increased in 4 of the 8 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater is 11.0 to 19.49 feet below ground surface. Robert Weimer
1/9/2013 Document, Report, or Work plan Review - other May 24, 2012 groundwater monitoring. Up to 150.0 mg/l GRO, 3.6 mg/l MTBE, 18,000 ug/l benzene, and non-detect lead, 1,2-DCA, and EDB in the groundwater samples collected. Contamination levels increased in 4 of the 10 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater is 9.02 to 16.51 feet below ground surface. Robert Weimer
1/16/2013 Conceptual Site Model Submitted Soil ingestion, groundwater ingestion, inhalation of outdoor air, and inhalation of indoor air are identified as completed pathways. Robert Weimer
2/5/2013 Document, Report, or Work plan Review - other First/Second quarter 2012 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated 73% in the first and second quarter, and removed approximately 53.9 pounds of GRO. Approximately 1,513 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Some ves lines were found to be frozen or to contain excess water. The consultant recommends continued operation of the AS/SVE system. Robert Weimer
2/5/2013 Document, Report, or Work plan Review - other August 2, 2012 groundwater monitoring. Up to 29.0 mg/l GRO, 1.2 mg/l MTBE, and 1,800 ug/l benzene. The monitoring well that previously had the highest contaminant concentrations (MW-4R) was not sampled this monitoring event due to insufficent water. Contamination levels increased in 2 of the 6 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater is 12.65 to 18.15 feet below ground surface. The consultant recommends continued semi-annual groundwater monitoring. Robert Weimer
2/27/2013 Meeting or Teleconference Held Meeting with Chevron and their consultants on 2/26/13. Chevron proposes to continue to conduct semi-annual groundwater monitoring, continued operation of the SVE/AS system, the property owner is looking at putting in a gas station/store on the property, if so Chevron will submit a management plan to deal with contaminated soil/groundwater that may be encountered during construction, monitoring wells, and remediation system. The next groundwater sampling event they will sample both using no purge and purge help evaluate that the past no purge results were providing comparable data. We discussed that all semi-annual monitoring events need to be at least 120 days apart. Robert Weimer
3/26/2013 Update or Other Action DEC conditionally approves the use of a portable activated carbon (gac) filter system for this site to treat water generated during groundwater monitoring. The storage of water at the site or the secure storage area at 1441 C Street is also approved. Robert Weimer
11/26/2013 Document, Report, or Work plan Review - other Second semi-annual 2012 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated 60% during this period, and removed approximately 105.2 pounds of GRO. Approximately 1,619 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. Some ves lines were found to be frozen or to contain excess water. The consultant recommends continued operation of the AS/SVE system. Robert Weimer
1/15/2014 Document, Report, or Work plan Review - other May 14, 2013 groundwater monitoring. Up to 58.3 mg/l GRO, 1.6 mg/l MTBE, and 3,300 ug/l benzene. Contamination levels increased in 2 of the 9 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 7.35 to 16.56 feet below ground surface. The consultant recommends continued semi-annual groundwater monitoring. Samples were collected by both no-purge (Hydrasleeve) and purge (bladder pump). The Hydrasleeve samples were collected from the top of the water column. The bladder pump sample depth was not documented. Robert Weimer
2/12/2014 Document, Report, or Work plan Review - other September 17, 2013 groundwater monitoring. Up to 9.1 mg/l GRO, 1.1 mg/l MTBE, and 2,000 ug/l benzene. Contamination levels increased in 3 of the 8 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 9.68 to 16.98 feet below ground surface. The consultant recommends continued semi-annual groundwater monitoring. Samples were collected by no-purge (Hydrasleeve). The Hydrasleeve samples were collected from the top of the water column. The previously most contaminated well (MW-3) was not accessible, that well needs to be located or replaced. Robert Weimer
2/20/2014 Update or Other Action Vapor Intrusion Evaluation Report - GRO and Benzene in soil and groundwater above cleanup levels. Consultant recommends VI investigation in 2014, with a work plan to be submitted in the spring of 2014. The property owner plans on building on the property in 2014. Robert Weimer
2/27/2014 Meeting or Teleconference Held Meeting with Chevron and their consultants on 2/27/2014. They plan to continue semi-annual groundwater monitoring. Because of planned site development in 2014/2015 the existing remediation system and many of the site monitoring wells may need to be removed. They will need a management plan for the handling of contaminated soil and groundwater during site development. Due to the high concentrations of remaining soil and groundwater contamination Chevron will need to install a replacement remediation system and/or excavate and treat the source areas during or prior to construction. Replacement monitoring wells will also be required. Because of problems with last year’s purge/no-purge sampling the next groundwater sampling event they will sample both using no purge and purge help evaluate that the past no purge results were providing comparable data or they will switch to no purge for future sampling events. We discussed that the groundwater samples needs to be collected as close as possible to the soil/water interface, with the pump intake within a foot of the soil/water interface at the time of the sampling. After reviewing the results of the May 2014 groundwater sampling event the consultant may be requesting a reduction in ground water monitoring. They still need a frozen ground soil gas sampling event and a non-frozen ground sampling event to help evaluated the vapor intrusion pathway. In the future they will need to evaluate for a diving plume on the monitoring wells far from the release point. The consultant will make sure that their site reports are complete in accordance with DEC’s 9/23/2009 Site Characterization Work Plan and Reporting Guidance for Investigation of Contaminated Sites. Chevron may need a letter from DEC requesting future active remediation. Robert Weimer
6/4/2014 Document, Report, or Work plan Review - other Because of the proposed development of the site by the property owner in 2014 the DEC has no objection to decommissioning as proposed in the April 2014 work plan the existing remediation system of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). As discussed in our meeting on February 27, 2014 DEC will need a management plan for the handling of contaminated soil and groundwater during site development. Due to the high concentrations of remaining soil and groundwater contamination, Chevron will need to install a replacement remediation system and/or excavate and treat the source areas during or prior to construction. Replacement monitoring wells will also be required. DEC requests that the management plan be submitted at least two weeks prior to any activities by the developer that might disturb site soils. DEC also requests a corrective action plan for the remaining soil and groundwater contamination be submitted by August 15, 2014. Robert Weimer
6/4/2014 Document, Report, or Work plan Review - other First semi-annual 2013 Remediation System Status Report. The upgraded system began operation in late February 2007. The system operated only 0.3% during this period, and removed approximately 0.04 pounds of GRO. Approximately 1,619.1 pounds of GRO have been removed since the system began operation in 1997. The upgraded system consists of 14 vapor extraction wells and 26 air sparge wells (in 6 banks of wells). The air sparge system began pulsed operation in April 2007. The system was not operated since February 1, 2013. VEW-2 had the highest PID reading (210 ppm) since March of 2010. Robert Weimer
7/21/2014 Update or Other Action DEC approves the request for an extention until December 15, 2014 to submit a corrective action plan for the remaining soil and groundwater contamination. Robert Weimer
10/8/2014 Meeting or Teleconference Held Teleconference with Chevron and their consultant (CRA), we discussed future active remediation of the site. They are thinking about excavating the most contaminated area soil area. They will submit a work plan that includes the treatment of the excavated soil, handling of contaminated water, and the installation of replacement monitoring wells. We discussed that confirmation soil samples would be required in the future and additional active remediation may be required based on the results of the cleanup. They plan to conduct excavation work in 2015 prior to site development by the property owner. Robert Weimer
10/8/2014 Document, Report, or Work plan Review - other May 1, 2014 groundwater monitoring. Up to 66.9 mg/l GRO, 3.2 mg/l MTBE, 3,100 ug/l benzene, 2.3 ug/l lead, and non-detect (<0.0044 ug/l) EDB. Contamination levels increased in 4 of the 9 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 7.52 to 15.82 feet below ground surface. The consultant recommends continued semi-annual groundwater monitoring. Samples were collected by no-purge (Hydrasleeve) and purge (bladder pump). The Hydrasleeve samples were collected from the top of the water column. The purge samples were not taken at the soil/water interface as required, they ranged from 1.0 feet to 2.86 feet below the soil/water interface, with 8 of 9 monitoring wells sampled at a depth of over 1.8 feet below the soil water/interface. The purge samples are considered biased low and can't be used for site closure or trend analysis. The results of the purge and no-purge sampling was not comparable. Monitoring well MW4R had 66.9 mg/l GRO and 3,100 ug/l benzene (purge) but had only 0.44 mg/l GRO and 4.2 ug/l benzene. Robert Weimer
2/4/2015 Document, Report, or Work plan Review - other October 3, 2014 groundwater monitoring. Up to 50.4 mg/l GRO, 2.0 mg/l MTBE, 870 ug/l benzene, 0.21 ug/l lead, and non-detect (<0.014 ug/l) EDB. Contamination levels increased in 5 of the 8 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 8.42 to 15.94 feet below ground surface. The consultant recommends continued semi-annual groundwater monitoring. Samples were collected by purge (bladder pump) method. The purge samples were not taken at the soil/water interface as required, they ranged from 1.0 feet to 2.97 feet below the soil/water interface, with 7 of 8 monitoring wells sampled at a depth of over 1.58 feet below the soil water/interface. The purge samples are considered biased low and can't be used for site closure or trend analysis. Robert Weimer
2/5/2015 Document, Report, or Work plan Review - other On June 9-10, 2014 CRA decommissioned 40 vertical air sparge and vapor extraction wells at the site. The remediation system had operated until February 1, 2013 and has been monitored since then for a rebound in the groundwater contamination. A total of 1,619.1 pounds of petroleum hydrocarbons were removed by that system. The piping was removed or filled with hydrated bentonite. The system was decommissioned in preparation for future site development planned for the summer of 2015. Robert Weimer
2/13/2015 Document, Report, or Work plan Review - other At the request of Chevron, their consultant CRA evaluated several technologies to remediate the remaining soil and groundwater at this site. They recommended land-based sulfate application at this site. DEC has no objection to this proposal, but will need a detailed corrective action plan, for review and approval on how, when, and where it will be implemented. The plan will need a site diagram showing the application area in relation to the existing soil and groundwater contamination. It will also need information as to the sulfate product and the calculations as to the application rate of that product. Once they have an approved plan they hope to conduct the sulfate application in 2015. Robert Weimer
2/20/2015 Update or Other Action DEC still has not received the management plan for the handling of contaminated soil and groundwater during site development as discussed in a meeting with Chevron on February 27, 2014. Due to the soil and groundwater contamination remaining over site cleanup levels, Chevron plans to conduct additional corrective action (land-based sulfate application) prior to construction. Replacement monitoring wells will also be required. DEC requested that a management plan (for soil and groundwater) be submitted at least two weeks prior to any activities by the developer that might disturb site soils or groundwater. DEC sent an email request for an update on the status of the management plan. Robert Weimer
2/25/2015 Meeting or Teleconference Held Teleconference with Chevron and their consultant CRA. By March 31, 2015 Chevron plans to submit a corrective action plan for the remediation of the remaining soil and ground water contamination at the site, a site management plan (soil and groundwater) for site development planned in 2015, and a vapor intrusion assessment plan for the collection of soil gas samples for the planned on-property development and for the building located just west of the property. Robert Weimer
3/9/2015 Meeting or Teleconference Held DEC project manager attended a Municipality of Anchorage Planning and Zoning Commission meeting to answer questions regarding this contaminated site and how future site development might impact on-going cleanup work. Chevron is to conduct additional corrective action and submit a soil and groundwater management plan by March 31, 2015. The property owner plans to develop the property as a Chevron branded gas station in 2015. This would include the installation of new underground storage tanks and their associated piping and dispensers. Robert Weimer
3/17/2015 Update or Other Action DEC conditionally approves request for an extension until July 17, 2015 to submit a site management plan (soil and groundwater) for site development planned in 2015. The approval is contingent on that the site management plan be submit for DEC review and approval at least 2 weeks prior to site development work. Robert Weimer
5/5/2015 Document, Report, or Work plan Review - other DEC approves March 2015 Sulfate Treatment Work Plan. The work plan proposes apply pulverized gypsum (calcium sulfate) on the ground surface over a 24,190 square foot area of the site and to apply water to help dissolve the sulfate to transport it into the underlying soil and groundwater. Robert Weimer
5/13/2015 Document, Report, or Work plan Review - other DEC comments on March 2015 Soil Vapor Assessment Work Plan. ADEC requests a revised work plan with the following modifications: 1. Need to complete Section I of the ADEC Building Inventory Form for each of the two buildings (off-property and the planned building on-property). 2. Need to confirm helium utilized in leak test is 100% helium certified. 3. Need confirm that helium will be measured under the shroud, and at the sample port to confirm is less than 10% is recovered to pass the test. All these measurements need to be documented in the report and field notes. 4. The sample tubing (to pump, helium shroud, and sample port) need to be constructed of Teflon and needs to be replaced between each soil gas probe. 5. Need to include a quality assurance section to ensure our QA requirements listed in the ADEC March 2009 technical memo are being followed. This section needs to discuss chain of custody procedures and confirm that canister pressures will be checked throughout the process to ensure results are acceptable. The canister pressure needs to be checked before and after sampling and upon receipt by the laboratory. Laboratory data review checklists need to be filled out, and the data validated by Conestoga-Rovers & Associates. 6. If nested wells are installed then oxygen, carbon dioxide, and methane concentrations need to be depicted on figures as a function of depth to show petroleum hydrocarbon attenuation in each area. 7. Need to analyze and report the full TO-15 list, not just BTEX. 8. Need to wait at least 1 week from soil vapor well installation until sampling. 9. Section 3.5 needs to reference the current October 2012 ADEC Vapor Intrusion Guidance. 10. Section 3.3 and Figure 3 need to be consistent as to the length of the vapor screen. 11. Section 3.4 need to purge a minimum of 3 volumes. 12. At a minimum we need a sampling event during frozen and non-frozen ground conditions. Robert Weimer
6/1/2015 Document, Report, or Work plan Review - other DEC approves request to apply sulfate over a slightly smaller area due to the coffee shop still being on-site. They will not be applying sulfate where the coffee shop is and the drive through area around the shop. Robert Weimer
6/1/2015 Site Visit Site visit to observe the surface application of the pulverized gypsum (calcium sulfate) on the ground surface and to apply water to help dissolve the sulfate to transport it into the underlying soil and groundwater. Robert Weimer
6/8/2015 Update or Other Action Update from consultant that they have applied 27,000 gallons of water on the surface of the site to dissolve the pulverized gypsum (calcium sulfate) to transport it into the underlying soil and groundwater. With the recent rain they think they have achieved the work plan goal of 36,000 gallons of water to the surface. Robert Weimer
7/30/2015 Update or Other Action DEC approves request for an extension until August 31, 2015 to submit a site management plan (soil and groundwater) for site development planned in 2015. Robert Weimer
4/29/2016 Document, Report, or Work plan Review - other May 5, 2015 groundwater monitoring. Up to 93.0 mg/l GRO, 0.93 mg/l MTBE, 3,000 ug/l benzene, non-detect lead, and non-detect EDB. Contamination levels increased in 3 of the 9 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 10.34 to 18.59 feet below ground surface. Some samples were collected by purge (bladder pump) method. Other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required. Robert Weimer
5/13/2016 Document, Report, or Work plan Review - other November 5, 2015 groundwater monitoring. Up to 71.0 mg/l GRO, 0.36 mg/l MTBE, 4,400 ug/l benzene, non-detect lead, and non-detect EDB. Samples were also analyzed for PAHs, with up to 29 ug/l naphthalene (1.65 ug/l proposed cleanup level), Contamination levels increased in 2 of the 8 monitoring wells sampled. Groundwater flow direction is to the northwest. Depth to groundwater 8.41 to 17.73 feet below ground surface. Some samples were collected by purge (bladder pump) method. Other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required except for monitoring well MW-10 that was collected from an interval of 2 to 5 feet below the soil/water interface. Robert Weimer
9/6/2016 Document, Report, or Work plan Review - other Between May 31, 2015 and June 3, 2015 pulverized gypsum (calcium sulfate) was applied on the ground surface over a 21,334 square foot area of the site and 27,000 gallons of water was applied to help dissolve the sulfate to transport it into the underlying soil and groundwater. Pre (5/5/2015) and post (11/5/2015) treatment groundwater samples were collected from the site monitoring wells, those within the treatment area showed an increase in sulfate concentrations. Within the source area (MW-4R) the GRO went from 82 mg/l to 69 mg/l and the benzene from 2,700 ug/l to 3,500 ug/l. The 120' downgradient monitoring well (MW-5R) the GRO went from 0.07 mg/l to 8.9 mg/l and the benzene from 13 ug/l to 2,900 ug/l. The monitoring wells (MW-16 and MW-11) further downgradient at 162' and 175' remained non-detect for GRO and benzene. Some of the groundwater samples were collected no-purge with Hyrasleeves and other by purge method with a bladder pump. All of the groundwater samples were collected within to top of the water column. Robert Weimer
4/13/2017 Document, Report, or Work plan Review - other September 26, 2016 groundwater monitoring. Up to 77.0 mg/l GRO, 0.36 mg/l MTBE, 4,300 ug/l benzene, 74 ug/l lead, and 0.038 ug/l EDB. Samples were also analyzed for PAHs, with up to 90 ug/l naphthalene (1.7 ug/l cleanup level), contaminant concentrations increased in 4 of the 8 monitoring wells sampled. Groundwater flow direction is to the southwest. Depth to groundwater 8.75 to 18.51 feet below ground surface. Some samples were collected by purge (bladder pump) method. Other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required. Robert Weimer
1/10/2018 Document, Report, or Work plan Review - other April 25-26, 2017 groundwater monitoring. Up to 56.0 mg/l GRO, and 2,900 ug/l benzene. Non-detect EDB in the one monitoring well sampled. Samples were also analyzed for PAHs, with up to 37 ug/l naphthalene (1.7 ug/l cleanup level), 34 ug/l acetophenone (260 ug/l cleanup level), 1.0 ug/l fluorine (290 ug/l cleanup level), 2-methylnaphthalene (36 ug/l cleanup level), and 0.3 ug/l phenanthrene (170 ug/l cleanup level) contaminant concentrations increased in 1 of the 8 monitoring wells sampled. Groundwater flow direction is to the southwest. Depth to groundwater 8.34 to 18.18 feet below ground surface. Some samples (MW-4R and MW-14) were collected by purge (bladder pump) method, the other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required. Robert Weimer
1/25/2018 Offsite Soil or Groundwater Disposal Approved DEC approves thermal treatment at ASR of 2 cubic yards of contaminated drill cuttings generated during the installation of the 6 vapor probes in 2017. Robert Weimer
3/29/2018 Document, Report, or Work plan Review - other October 4-5, 2017 groundwater monitoring. Up to 22.0 mg/l GRO, and 5,800 ug/l benzene. Non-detect EDB and lead in the one monitoring well (MW-4R) sampled. Samples were also analyzed for PAHs, with up to 46 ug/l naphthalene (1.7 ug/l cleanup level), 0.5 ug/l acetophenone (260 ug/l cleanup level), 9.0 ug/l fluorine (290 ug/l cleanup level), and 0.3 ug/l phenanthrene (170 ug/l cleanup level) contaminant concentrations increased in 5 of the 8 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater 8.71 to 18.18 feet below ground surface. Some samples (MW-4R and MW-14) were collected by purge (bladder pump) method, the other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required. Robert Weimer
7/13/2018 Document, Report, or Work plan Review - other April 23, 2018 groundwater monitoring. Up to 18.0 mg/l GRO, 200 ug/l MTBE, and 4,400 ug/l benzene. Non-detect EDB and lead in the one monitoring well (MW-4R) sampled. Samples were not analyzed for PAHs. Contaminant concentrations increased in 4 of the 9 monitoring wells sampled. Groundwater flow direction is to the west. Depth to groundwater 8.71 to 18.18 feet below ground surface. Some samples (MW-4R and MW-14) were collected by purge (bladder pump) method, the other samples were collected no-purge method using HydraSleeves. The samples were collected from the top of the water column as required. Robert Weimer
7/13/2018 Update or Other Action DEC requests until further notice that all of the samples be collected after purging, that the samples be collected within the top foot of the water column using a method that minimizes the loss of volatiles, such as the bladder pump that they are using on some of the monitoring wells at this site. Robert Weimer
1/10/2019 Document, Report, or Work plan Review - other September 26, 2017 soil gas sampling event during non-frozen ground conditions. Six soil gas probes were sampled. These probes were installed on August 14-15, 2017 and they were all installed to a depth of 6.5 feet below ground surface. Three are located in the area of the proposed store building and three more are located on the east side of the strip mall building located on the property to the east of the gas station property. Only benzene at 160 ug/m3 was detected at DEC soil gas commercial (160 ug/m3) or over residential target levels (36 ug/m3). The report recommends and additional non-frozen ground sampling event to evaluate concentrations. The rest of the detected analytes were below 10% of the commercial target levels. Since no helium was detected in any of the samples the testing system and surface seals appear to be tight. Robert Weimer
1/10/2019 Document, Report, or Work plan Review - other January 30, 2018 soil gas sampling event during frozen ground conditions. Six soil gas probes were sampled. These probes were installed on August 14-15, 2017 and they were all installed to a depth of 6.5 feet below ground surface. Three are located in the area of the proposed store building and three more are located on the east side of the strip mall building located on the property to the east of the gas station property. All of the detected analytes were below 10% of the commercial target levels. Since helium was detected in all of the samples the surface seals don't appear to be tight and the results are considered biased low due to surface air being included with the soil gas. The calculated leak rate was calculated to be between 12.3% and 64.0%, with an average of 44.9%. Robert Weimer
1/18/2019 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 77950 1992 UST contamination. Robert Weimer
4/1/2019 Document, Report, or Work plan Review - other August 29, 2018 groundwater monitoring. Up to 8.5 mg/l GRO, 110 ug/l MTBE, and 3,700 ug/l benzene. Non-detect EDB and lead in the one monitoring well (MW-4R) sampled. Samples were not analyzed for PAHs. Contaminant concentrations increased in 2 of the 8 monitoring wells sampled. Groundwater flow direction is to the west by southwest. Depth to groundwater 9.18 to 18.80 feet below ground surface. All of the samples were collected by purge (bladder pump) method from the top of the water column as required. Robert Weimer
9/13/2019 Document, Report, or Work plan Review - other September 25, 2018 soil gas sampling event during frozen ground conditions. Only one soil gas probe (SVE-5) was sampled this monitoring event. This probe exceeded screening levels for benzene on September 26, 2017. These probes were installed on August 14-15, 2017 and they were all installed to a depth of 6.5 feet below ground surface. Three are located in the area of the proposed store building and three more are located on the east side of the strip mall building located on the property to the east of the gas station property. All of the detected analytes were below 10% of the commercial target levels. Since helium was detected in all of the samples the surface seals don't appear to be tight and the results are considered biased low due to surface air being included with the soil gas. The calculated leak rate was calculated to be between 10.6% and 16.3%, with an average of 14%. DEC guidance considers there being excessive leakage on any sample greater than 10%. Robert Weimer
9/23/2019 Update or Other Action ADEC requests for this site that the monitoring wells are purged prior to sampling, and that the intake of the bladder pump/in-well pump be documented in the field notes to be within the top foot of the water column at the time of the sampling. Also VOC sampling needs to include the full 8260 VOC list including naphthalene. Robert Weimer
12/19/2019 Document, Report, or Work plan Review - other 2019 First Semi-Annual Groundwater Monitoring event was conducted on April 23, 2019. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, and MW-16. Samples were submitted to the laboratory for GRO, BTEX, and MTBE, samples collected from MW-4R were also analyzed for lead and 1,2-dibromoethane. Groundwater flow direction was to the west-northwest and depth to groundwater was 9.13 to 17.62 feet below ground surface. Rebekah Reams
12/31/2019 Document, Report, or Work plan Review - other 2019 Second Semi-Annual Groundwater Monitoring event was conducted on September 19, 2019. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, and MW-16. Samples were submitted to the laboratory for GRO, BTEX, sampled collected from MW-5R, MW-7, and MW-10 were analyzed for MTBE and samples collected from MW-4R were also analyzed for lead and 1,2-dibromoethane. Groundwater flow direction was to the southwest and depth to groundwater was 9.43 to 19.90 feet below ground surface. Rebekah Reams
3/12/2020 Update or Other Action ADEC requests for this site that the monitoring wells are purged prior to sampling, and that the intake of the bladder pump/in-well pump be documented in the field notes to be within the top foot of the water column at the time of the sampling. Also all BTEX and VOC sampling needs to include the full 8260 VOC list including naphthalene. ADEC is also requesting that all reports be submitted within 60 days of the sampling and the groundwater monitoring figure include a diagram showing historic groundwater flow directions. Robert Weimer
3/17/2020 Document, Report, or Work plan Review - other DEC reviewed 2020 groundwater sampling plan and provided the following comments: For all future monitoring events please make sure that the field notes document the measurement of the pump intake that is within the top foot of the water column at the time of the sampling unless the top of the well screened interval is deeper, then in that case from the top foot of that screened interval. For all future monitoring events any monitoring well where BTEX or HVOC sampling is proposed it needs to be the full VOC (method 8260) list, including naphthalene. The field QC samples are per day of sampling at a site. For all future monitoring events all reports be submitted within 60 days of the sampling and the groundwater monitoring figure include a diagram showing historic groundwater flow directions. For all future monitoring events if a monitoring well is low yield and purges dry then a sample will still need to be collected that monitoring event once the monitoring well has recharged to approximately 80% of its pre-purge volume. If it has not returned to 80% of its pre-purged volume during that sampling day DEC requests that you return to the site early the next day to attempt to collect the water sample. Robert Weimer
6/4/2020 Document, Report, or Work plan Review - other 2020 First Semi-Annual Groundwater Monitoring event was conducted on April 13 and 14, 2020. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, and MW-16. Monitoring wells MW-9, MW-12, MW-14 and MW-17 were unable to be located due to snow. Well MW-10 was unable to be gauged or sampled due to ice in well vault. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 11.10 to 19.16 feet below ground surface. Rebekah Reams
12/14/2020 Document, Report, or Work plan Review - other 2020 Second Semi-Annual Groundwater Monitoring event was conducted on October 15th and 17th, 2020. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, MW-16 and MW-17. Monitoring well MW-12 was unable to be located. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 9.55 to 18.54 feet below ground surface. Rebekah Reams
1/15/2021 Meeting or Teleconference Held DEC staff met with Chevron Environmental Management Company (CEMC) and Arcadis to discuss Chevron sites located in Alaska during the Annual Portfolio Meeting on January 14th and 15th, 2021. Rebekah Reams
6/18/2021 Document, Report, or Work plan Review - other 2021 First Semi-Annual Groundwater Monitoring event was conducted on April 15th, 2021. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, MW-16 and MW-17. Monitoring well MW-12 was unable to be located due to snow. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 10.15 to 19.44 feet below ground surface. Rebekah Reams
11/8/2021 Document, Report, or Work plan Review - other 2021 Second Semi-Annual Groundwater Monitoring event was conducted on September 2nd and 3rd, 2021. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, MW-16 and MW-17. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 8.81 to 18.21 feet below ground surface. Rebekah Reams
7/20/2022 Long Term Monitoring Workplan or Report Review 2022 First Semi-Annual Groundwater Monitoring event was conducted on April 13th, 2022. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-11, MW-14, MW-16 and MW-17. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 6.74 to 16.68 feet below ground surface. Rebekah Reams
9/29/2022 Document, Report, or Work plan Review - other ADEC provided comments on the Treatment of Purge Water Utilizing Granular Activated Carbon (GAC) at Chevron Environmental Management Company Sites which includes standard operating procedures and breakthrough estimates proposed for use at this site. Rebekah Reams
12/23/2022 Offsite Soil or Groundwater Disposal Approved DEC approved transport of one 55-gallon drum of purge water for offsite disposal Rebekah Reams
7/27/2023 Document, Report, or Work plan Review - other 2022 Second Semi-Annual Groundwater Monitoring event was conducted on September 5th, 2022. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-10, MW-11, MW-14, MW-16 and MW-17. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the west-southwest and depth to groundwater was 7.48 to 16.28 feet below ground surface. Rebekah Reams
7/27/2023 Document, Report, or Work plan Review - other 2023 First Semi-Annual Groundwater Monitoring event was conducted on April 17th and 18th, 2023. Groundwater samples were collected from monitoring wells MW-3, MW-4R, MW-5R, MW-7, MW-8, MW-9, MW-10, MW-11, MW-14, MW-15, MW-16 and MW-17. Samples were submitted to the laboratory for VOCs and GRO and samples collected from MW-4R were also analyzed for lead. Groundwater flow direction was to the northwest and depth to groundwater was 9.15 to 18.35 feet below ground surface. Rebekah Reams
8/31/2023 Long Term Monitoring Workplan or Report Review ADEC approved the Groundwater Analyte Adjustment Request following comment resolution. This work plan proposes to update the analytes included in the groundwater monitoring plan to include DRO, GRO, BTEX, MTBE, EDC, EDB, naphthalene, cumene, propylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3-trichloropropane, and lead. Rebekah Reams
11/16/2023 Offsite Soil or Groundwater Disposal Approved ADEC approved offsite transport of one 55-gallon drum of purgewater. Rebekah Reams
11/30/2023 Site Visit ADEC staff visited the site to observe current site use, layout, and monitoring well locations. Rebekah Reams
3/20/2024 Document, Report, or Work plan Review - other ADEC provided comments on the Conceptual Site Model Summary and Data Gap Investigation Work Plan which summarizes past investigations at this site, identifies data gaps to be addressed prior to site closure, and proposes to advance soil borings and collect analytical soil and soil gas samples to evaluate current site conditions following remediation activities at the site Rebekah Reams

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State of Alaska Department of Environmental Conservation

P.O. Box 111800
Juneau, AK 99811-1800
Phone: 907-465-5066
Fax: 907-465-5245
TDD: 800-770-8973
Physical Location: 410 Willoughby