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Site Report: Unocal - #4652 (former) Chevron 306448

Site Name: Unocal - #4652 (former) Chevron 306448
Address: 1441 C St., Anchorage, AK 99501
File Number: 2100.26.117
Hazard ID: 23360
Status: Active
Staff: Rebekah Reams, 9074512144 rebekah.reams@alaska.gov
Latitude: 61.207958
Longitude: -149.886904
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

A 600 gallon gasoline leak from UST facility contaminates soil/groundwater in 1986. Some contaminated soils and all of the underground storage tanks were removed in 1987. Diesel fuel contamination was also found during the tank removal. Soil and groundwater contamination extend off property to the south. Soil vapor extraction treatment system and groundwater collection trenches are installed in 1988. Site under a Compliance Order By Consent (COBC) since 1988. In 1991, 200 cubic yards of contaminated soil was mixed into cold asphalt and applied to the surface of the property, which will need to be disposed of in accordance with a approved plan when it is removed. Also in 1991 additional contaminated soil was transported to a soil treatment cell at the 9760 Old Seward property where it was successfully treated. In 2003 about 2,000 tons of contaminated soil was removed from the downgradient property and thermally treated. Replacement monitoring wells were installed in 2005. In December 2014 the passive groundwater collection trench across the street from the gas station property on the south side of 15th Avenue was decommissioned. Groundwater monitoring is continuing at this site until confirmation soil and groundwater samples demonstrate that the site meets cleanup levels. The contaminated soil that was mixed into cold asphalt and applied to the surface of the property will need to be disposed of in accordance with a approved plan when it is removed.

Action Information

Action Date Action Description DEC Staff
7/25/1986 Site Added to Database Former Staff
7/25/1986 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 77986 A 600 gallon gasoline leak. Former Staff
7/26/1986 Leaking Underground Storage Tank Cleanup Initiated - Petroleum LCAU Date changed DB conversion Former Staff
8/1/1986 Release Investigation Interim Report, Subsurface Product Loss Evaluation, Unocal Service Station, 15th Avenue and C Street, Anchorage, Alaska, September 1986 by RZA, Inc. Free gasoline product found at the site. Former Staff
11/1/1987 Underground Storage Tank Site Characterization or Assessment Contamination Assessment Report, Unocal Station 4652, January 1989 by RZA indicates: TPH up to 5,170 mg/kg in soil; Benzene up to 4.65 mg/kg in soil; 8.0 mg/l TPH in water; 58,800 ug/l of BTEX in water; at least a 150 foot by 150 foot area cis ontaminated in both soil and water. Former Staff
11/4/1987 Document, Report, or Work plan Review - other Proposed off property monitoring plan, November 4, 1987 by RZA. Former Staff
3/24/1988 Leaking Underground Storage Tank Corrective Action Underway Soil Disposal Plan, March 24, 1988 by RZA. Former Staff
12/21/1988 Site Visit Site visit to observe quarterly sampling of the site groundwater monitoring wells conducted by RZA. Former Staff
2/7/1989 Document, Report, or Work plan Review - other Supplemental Contamination Assessment report dated April 1989 submitted by RZA. Former Staff
3/1/1989 Document, Report, or Work plan Review - other Remedial Action Plan dated March 1989 submitted by RZA. Former Staff
9/21/1989 Risk Assessment Technical Requirements for Risk Assessment, August 21, 1989 by Shannon & Wilson; Final version August 1989. Former Staff
1/10/1990 Document, Report, or Work plan Review - other Remediation Status Report and As-Built Documentation submitted. Former Staff
4/19/1990 Document, Report, or Work plan Review - other Mr. Rader owning property downgradient of site to the south across 15th Avenue submitted Dames & Moore assessment of contamination on his property downgradient from the Unocal gas station property. Mr. Rader requests further cleanup by Unocal. Former Staff
4/26/1990 Document, Report, or Work plan Review - other RZA assessment of soil and groundwater impacts on Rader property. Former Staff
8/8/1990 Update or Other Action ADEC letter sent 8/8/90 to Unocal: Need to have collection trench and membrane fabric installed to prevent further contamination migration, site capped, a soil disposal/treatment plan for review by 8/31/90, and ADEC does not waive its rights to seek stipulated penalties. Former Staff
9/27/1990 Update or Other Action ADEC stipulations on contaminated soils mixed in cold asphalt and placed on the surface of the property are: not to be used as parking; TCLP for contaminated soils; ultimate disposal plan for asphalt sealant is removed from site. Former Staff
11/9/1990 Document, Report, or Work plan Review - other Sept. 90 monthly progress report needs to include information on: overall amount of mass recovery obtained from both air stripped and vapor extraction system, daily mean air emission concentrations for both systems. Request also that boring logs for the 4 new monitoring wells be produced in report. Former Staff
1/9/1991 Document, Report, or Work plan Review - other RZA remediation progress report. Vapor venting & water treatment system operated continuously for Dec. Approximately 419,311 gallons of water has been collected, treated, & discharged to sanitary sewer. Effluent samples are below the levels allowable by AWWU. Former Staff
2/12/1991 Document, Report, or Work plan Review - other RZA sent in remediation progress report for site activities since 1/8/91. Treatment system operated continuously except for power outage from 1/28/91 to 1/30/91. 671 gallons per day discharged to sanitary sewer. Total volume discharged to date 440,296 gallons. Lab analyses of effluent shows discharge below levels allowable through AWWU. Former Staff
3/1/1991 Document, Report, or Work plan Review - other RZA remediation progress report. Vapor venting system operated continuously for March '91. Water treatment system operated from 2/91-3/18/91 when it was shutdown for maintenance. Discharge from water treatment system is 570 gallons/day with effluent samples well below AWWU levels allowable. Former Staff
5/1/1991 Document, Report, or Work plan Review - other RZA progress report. Vapor extraction & water treatment system continue to operate throughout the monitoring period. Discharges from water treatment system average 1,050 gallons/day. Lab results of effluent continues to meet allowable levels for discharge into the AWWU sanitary sewer. Former Staff
6/1/1991 Document, Report, or Work plan Review - other RZA sent in progress report for remediation activities at site. Vapor venting system operated continuously for June '91 and water treatment system discharge 846 gallons/day. 200 cubic yards of petroleum contaminated soils converted into a cold mix asphalt product and applied to surface across project site on 6/26/91. Former Staff
7/1/1991 Document, Report, or Work plan Review - other RZA sent in progress report for vapor venting system & water treatment system. Water treatment discharges averaged 655 gallons/day from 7/1 to 7/31. Total volume at 564,357 gallons. Sampling of influent & effluent water showed non detect for all parameters tested. Former Staff
1/2/1992 Cleanup Level(s) Approved Under compliance order by consent #88-2-1-1-138-2 risk assessment approved by ADEC. Alternative cleanup levels (ACL) approved for benzene in the groundwater: 10 to the -5 risk level and 6,240 ug/1 benzene in the groundwater for on property groundwater contamination. No ACL was approved for other contaminants in groundwater. No ACL was approved for soil contamination. Former Staff
7/13/1992 Document, Report, or Work plan Review - other Progress reports received and reviewed for 15th and C Unocal; April '92 and June '92 for VES and groundwater treatment. Influent had 0.034 benzene mg/l on 6/18/92. Former Staff
8/28/1992 Update or Other Action Letter from ADEC to RZA (UNOCAL) in response to request of Aug 6, 1992 and data from Summary Report of May 1992. Decisions to modify the compliance order include; suspend sampling on monitoring wells 4, 5, 12, 13, 14, 15, and 16. Continue sampling MW 17. Analyses are suspended on all wells for gasoline and diesel range petroleum hydrocarbons, TPH, and oil and grease. Analyses still required for BTEX, chlorobenzene and dichlorobenzene. Additional information is required before decision can be made to convert VES to bioremediation system. Former Staff
11/20/1997 Update or Other Action ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: UNOCAL - ENVIRONMENTAL COMPLIANC Former Staff
12/16/1997 Document, Report, or Work plan Review - other Reviewed a hydrology report. Former Staff
8/18/2003 Document, Report, or Work plan Review - other Approved CAP to excavate all of the contamination on the Rader's property to default levels and treat soil at ASR. Robert Weimer
9/29/2003 Document, Report, or Work plan Review - other Reviewed report of the excavation and treatment of 2000 tons of contaminated soil from the Rader property. Some soil contamination remains near 15th and C Streets. Robert Weimer
4/7/2004 Update or Other Action ADEC issues a Notice of Environmental Soil and Groundwater Contamination for the downgradient (Rader) property to help facilitate the sale and development of that property. Robert Weimer
8/12/2004 Update or Other Action Meeting with Unocal. They will submit a workplan for the installation of 3 monitoring wells on the downgradient property, and to conduct long-term monitoring. Robert Weimer
9/17/2004 Update or Other Action Approved workplan to install 3 monitoring wells on the downgradient property (former Rader) and to collect soil and groundwater samples. Robert Weimer
11/30/2004 Update or Other Action ADEC conditionally approved a revised monitoring well locations. MW-21 is to be moved so it is downgradient of contaminated soil along C Street. Robert Weimer
3/18/2005 Update or Other Action Three new monitoring wells were installed in the downgradient property on 12/1/04. One soil sample had 0.0298 mg/kg benzene. Robert Weimer
3/18/2005 Update or Other Action ADEC approves the thermal treatment of the benzene contaminated drill cuttings. Robert Weimer
4/25/2005 Update or Other Action Meeting with RP and consultant to discuss future site work. They will submit a plan to abandon unused monitoring wells, propose groundwater monitoring, and restore site. Also discussed disposal of the cold asphalt and the status of MW-6A. They are to provide the results of the most recent groundwater sampling. Robert Weimer
8/12/2005 Document, Report, or Work plan Review - other March 29, 2005 groundwater monitoring event. Up to 665 ug/l benzene, 46.2 mg/l GRO, and 8.9 mg/l DRO in the groundwater. The contamination levels in the monitoring well (MW-20) closest to the original release point has increased from the previous monitoring event. The groundwater flow direction is to the south. Robert Weimer
5/5/2006 Document, Report, or Work plan Review - other December 31, 2005 groundwater monitoring event. Up to 844 ug/l benzene, 60.1 mg/l GRO, and 11.0 mg/l DRO in the groundwater. The contamination levels in the monitoring well (MW-20) closest to the original release point has increased from the previous monitoring event. The groundwater flow direction is to the south. The depth to groundwater was 7.5 to 10.5 feet below ground surface. Robert Weimer
1/25/2007 Document, Report, or Work plan Review - other June 30, 2006 groundwater monitoring event. Up to 800 ug/l benzene, 58.5 mg/l GRO, and 10.9 mg/l DRO in the groundwater. The contamination levels increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the south. The depth to groundwater was 6.5 to 10.7 feet below ground surface. Robert Weimer
3/28/2007 Document, Report, or Work plan Review - other September 18, 2006 groundwater monitoring event. Up to 350 ug/l benzene, 23 mg/l GRO, and 5.6 mg/l DRO in the groundwater. The contamination levels increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the south. The depth to groundwater was 5.2 to 10.3 feet below ground surface. Robert Weimer
4/2/2007 Update or Other Action Meeting with RP to discuss site. They are to locate Stephan's Tools property soils, to continue semi-annual groundwater monitoring, and information regarding status of cold asphalt at the site. Robert Weimer
4/27/2007 Document, Report, or Work plan Review - other March 5, 2007 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged between 1.2 and 0.6 gallons per minute during the third and fourth quarters of 2006. The water had 0.037 mg/l GRO and 5.3 ug/l benzene. Robert Weimer
6/29/2007 Document, Report, or Work plan Review - other June 29, 2007 groundwater monitoring event. Up to 500 ug/l benzene, 43 mg/l GRO, and 8.0 mg/l DRO in the groundwater. The contamination levels increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater is generally 5 to 10 feet below ground surface. Results may be biased low due to elevated sample temperature. 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. They are to continue semi-annual monitoring. Prior to closure confirmation soil samples will need to be collected. Robert Weimer
4/2/2008 Update or Other Action ADEC received notification that 20 gallons of contaminated purge water had spilled from a leaking drum. Robert Weimer
4/21/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of 80 gallons of contaminated purge water. Robert Weimer
4/22/2008 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
5/20/2008 Document, Report, or Work plan Review - other October 4, 2007 groundwater monitoring event. Up to 220 ug/l benzene, 29 mg/l GRO, 5.3 mg/l DRO in the groundwater, non-detect(<0.0096 ug/l) EDB, and 6 ug/l 1,2-DCA (0.5 ug/l is the cleanup level). The contamination decreased from the previous monitoring event. The groundwater flow direction is to the southeast. The depth to groundwater was 5.18 to 9.82 feet below ground surface. Robert Weimer
6/5/2008 Site Visit Site visit with UNOCAL/Chevron's consultant (CRA) to observe the condition of the soil treatment cell at Stephan's/United Tool Rental and to conduct confirmation sampling. Confirmation sampling was not done at this time because of changes in site conditions. The soil treatment cell had been graded and spread over a larger area, there may have been fill placed over portions, there were trailers and equipment were parked on portions of the treatment cell area, and there were some visibly stained soil in the cell area some of which was under the stored equipment. There were also some visibly stained soil under some equipment stored to the east of the treatment cell area. CRA said they would talk with the property owner and Chevron about what they observed. Robert Weimer
7/15/2008 Site Visit At the request of Robert Weimer, the project manager, a quality assurance site inspection was conducted on July 15, 2008. Upon arival, the quality assurance officer was onsite to observe sampling of MW-11A and MW-20. No deviations from standard sampling practices were observed on either wells. A copy of the site inspection report will be placed in the site file and in the QA file. Brenton Porter
8/4/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of contaminated purge water. Robert Weimer
9/2/2008 Document, Report, or Work plan Review - other ADEC conditionally approves the August 25, 2008 Soil Assessment Workplan. The workplan proposes to drill and sample 10 soil borings to assess current contaminate levels in the soil at the site. The soil samples are to be analyzed for BTEX, GRO, DRO, EDB, and 1,2-DCA. Robert Weimer
9/25/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of contaminated purge water. Robert Weimer
10/30/2008 Offsite Soil or Groundwater Disposal Approved ADEC approves thermal treatment of one drum of contaminated drill cuttings from the October 2008 confirmation sampling. Robert Weimer
12/15/2008 Document, Report, or Work plan Review - other June 19, 2008 groundwater monitoring event. Up to 300 ug/l benzene, 21 mg/l GRO, 4.6 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 6.5 to 10.58 feet below ground surface. The sample results may be biased low due to QA/QC problems. Robert Weimer
12/15/2008 Document, Report, or Work plan Review - other September 10, 2008 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.8 gallons per minute during the first quarter of 2008 (104,832 gallons). The water had 0.005 mg/l GRO and 0.868 ug/l benzene. Robert Weimer
12/31/2008 Document, Report, or Work plan Review - other October 10, 2008 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.58 gallons per minute during the second quarter of 2008 (76,003 gallons). The water had 0.007 mg/l GRO and 3.0 ug/l benzene. Robert Weimer
12/31/2008 Document, Report, or Work plan Review - other October 10, 2008 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.45 gallons per minute during the third quarter of 2008 (59,616 gallons). The water had 0.012 mg/l GRO and 6.0 ug/l benzene. Robert Weimer
2/19/2009 Update or Other Action LUST site created in CSP database for source area 1986 UST release, 78709 Robert Weimer
2/25/2009 Meeting or Teleconference Held Meeting with Chevron and their consultants. They are to conduct an evaluation of indoor air at this site. They are to submit a report on the release investigation work conducted in 2008. They are going to evaluated remediation options and pilot testing in 2009/2010. Site monitoring is to continue. Robert Weimer
6/18/2009 Offsite Soil or Groundwater Disposal Approved ADEC approves request for treatment of one drum of monitoring well purge water. Robert Weimer
6/22/2009 Site Visit At the request of Robert Weimer, the project manager, a quality assurance site inspection was conducted on 5/14/09. Upon arival, the consultant had completed sampling five of the six wells and field observations were made on sampling the final well. No deviations from standard sampling practices were observed on that well. A copy of the site inspection report will be placed in the site file and in the QA file. Brenton Porter
7/6/2009 Update or Other Action November 24, 2008 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.99 gallons per minute during the fourth quarter of 2008 (131,155 gallons). The water had 0.010 mg/l GRO and 4.0 ug/l benzene. Robert Weimer
7/6/2009 Update or Other Action August 28, 2008 groundwater monitoring event. Up to 300 ug/l benzene, 26 mg/l GRO, 4.5 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 4 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 6.97 to 10.72 feet below ground surface. Robert Weimer
7/8/2009 Underground Storage Tank Site Characterization or Assessment Subsurface investigation report review. On October 9, 2008 ten soil borings were sampled to help assess the current soil contamination levels at the site. The consultant recommends additional assessment to define the vertical extent of the soil contamination at the site and to evaluate remedial alternatives that would be effective the low permeability contaminated soils at the site. Up to 3.2 mg/kg benzene, 630 mg/kg GRO, 520 mg/kg DRO, non-detect (<0.079 mg/kg) 1,2-DCA (0.016 mg/kg cleanup level, and non-detect (<0.079 mg/kg) EDB (0.00016 mg/kg cleanup level) in the soils sampled. DRO results are biased low because silica gel cleanup was conducted on them prior to analysis, and no standard DRO analysis was conducted prior to silica gel cleanup for comparison. Robert Weimer
8/27/2009 Site Visit At the request of the project manager a site visit was conducted by the quality assurance officer. montioring well sampling was conducted and samples were collected from the sewage outfall located offsite. Brenton Porter
10/13/2009 Document, Report, or Work plan Review - other February 21, 2009 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 2.62 gallons per minute during the fourth quarter of 2008 (339,818 gallons). The water was non-detect for GRO and benzene. Robert Weimer
10/14/2009 Document, Report, or Work plan Review - other May 14, 2009 groundwater monitoring event. Up to 400 ug/l benzene, 38 mg/l GRO, 5.4 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 1 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 3.33 to 14.11 feet below ground surface. Robert Weimer
10/23/2009 Document, Report, or Work plan Review - other May 14, 2009 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.27 gallons per minute during the first quarter of 2009 (165,147 gallons). The water had 0.015 mg/l GRO and 1.4 ug/l benzene. Robert Weimer
1/11/2010 Document, Report, or Work plan Review - other August 27, 2009 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.27 gallons per minute during the third quarter of 2009 (177,696 gallons). The water had 0.12 mg/l GRO and 6.6 ug/l benzene. Robert Weimer
1/26/2010 Document, Report, or Work plan Review - other October 7, 2009 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 2.33 gallons per minute during the fourth quarter of 2009 (301,863 gallons). The water had 6.0 ug/l benzene. Robert Weimer
2/2/2010 Document, Report, or Work plan Review - other August 27, 2009 groundwater monitoring event. Up to 220 ug/l benzene, 18 mg/l GRO, 2.6 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 3 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 6.87 to 10.41 feet below ground surface. They recommend and continue monitor the passive groundwater collection system on a semi-annual basis. Robert Weimer
3/11/2010 Meeting or Teleconference Held Meeting with Chevron and their consultants on 3/10/10. MW11A & MW20 are to be sampled for PAH the next monitoring event. 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
5/20/2010 Update or Other Action Approved, until further notice, no-purge groundwater sampling at this site. Robert Weimer
8/27/2010 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of contaminated purge water. Robert Weimer
10/25/2010 Document, Report, or Work plan Review - other February 26, 2010 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.06 gallons per minute during the first quarter of 2010 (137,376 gallons). The water was non-detect for benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis. Robert Weimer
3/17/2011 Document, Report, or Work plan Review - other June 8, 2010 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.32 gallons per minute during the second quarter of 2010 (172,973 gallons). The water had 2.3 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis. Robert Weimer
7/21/2011 Document, Report, or Work plan Review - other December 13, 2010 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.22 gallons per minute during the third quarter of 2010 (158,112 gallons). The water was non-detect for benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis. Robert Weimer
7/26/2011 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of contaminated purge water. Robert Weimer
8/2/2011 Document, Report, or Work plan Review - other June 8, 2010 groundwater monitoring event. Up to 240 ug/l benzene, 29 mg/l GRO, 6.2 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 6.21 to 10.60 feet below ground surface. They recommend and continue monitor the passive groundwater collection system on a semi-annual basis. Robert Weimer
8/16/2011 Document, Report, or Work plan Review - other ADEC approves request to purge monitoring wells prior to sampling. Purging and sampling will be conducted using a bladder pump. Robert Weimer
10/12/2011 Document, Report, or Work plan Review - other January 2010 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.13 gallons per minute during the fourth quarter of 2010 (149,702 gallons). The water had 1.9 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis. Robert Weimer
10/12/2011 Document, Report, or Work plan Review - other August 6, 2010 groundwater monitoring event. Up to 280 ug/l benzene, 32 mg/l GRO, 6.6 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 4 of the 5 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 6.73 to 10.23 feet below ground surface. They recommend and continue monitor the passive groundwater collection system on a semi-annual basis. Robert Weimer
10/24/2011 Offsite Soil or Groundwater Disposal Approved ADEC approves treatment of contaminated purge water. Robert Weimer
11/18/2011 Document, Report, or Work plan Review - other May 2011 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.95 gallons per minute during the first quarter of 2011 (122,634 gallons). The water had 1.8 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
12/13/2011 Document, Report, or Work plan Review - other August 2011 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 2.26 gallons per minute during the second quarter of 2011 (296,150 gallons). The water had 1.6 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/29/2012 Meeting or Teleconference Held Meeting with Chevron and their consultants on 2/28/12. Chevron is to continue semiannual groundwater monitoring and quarterly effluent sampling for the collection trench. Robert Weimer
7/16/2012 Document, Report, or Work plan Review - other December 2011 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 1.22 gallons per minute during the fourth quarter of 2011 (108,922 gallons). The water had 1.9 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
8/17/2012 Offsite Soil or Groundwater Disposal Approved ADEC approves offsite treatment of contaminated purge water. Robert Weimer
9/19/2012 Document, Report, or Work plan Review - other March 2012 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.73 gallons per minute during the first quarter of 2012 (95,660 gallons). The water had 0.7 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
10/8/2012 Document, Report, or Work plan Review - other Review of Soil Cell Assessment Report for the September 2011 sampling of the soil treatment cell at the 9760 Old Seward property. The cell contained contaminated soil from several Unocal sites. Two visibly stained areas were sampled had up to 4,000 mg/kg DRO and 12,000 mg/kg RRO. The contaminated soil from these locations was excavated and thermally treated. Confirmation soil samples were collected from within the cell, under the cell liner, and around the perimeter of the cell. Up to 120 mg/kg DRO, 1,600 mg/kg RRO, background metals concentrations, non-detect PCBs, non-detect HVOCs, low concentrations of PAHs, and 0.006 mg/kg benzene in the soil samples collected. Robert Weimer
11/27/2012 Update or Other Action Review the revised Industrial Discharge Permit Application for the passive groundwater collection trench water discharge to the sanitary sewer for 500,000 to 1,000,000 gallons per year. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
1/16/2013 Document, Report, or Work plan Review - other Second Quarter 2012 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.63 gallons per minute during the second quarter of 2012 (83,027 gallons). The water had 2.0 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
1/16/2013 Document, Report, or Work plan Review - other May 19, 2011 groundwater monitoring event. Up to 410 ug/l benzene, 34 mg/l GRO, 6.0 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 5 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. Robert Weimer
1/16/2013 Document, Report, or Work plan Review - other August 6, 2011 groundwater monitoring event. Up to 420 ug/l benzene, 40 mg/l GRO, 5.3 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 1 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. Robert Weimer
1/16/2013 Document, Report, or Work plan Review - other May 28-31, 2012 groundwater monitoring event. Up to 270 ug/l benzene, 33 mg/l GRO, 4.7 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 5 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 5.51 to 10.30 feet below ground surface. They recommend and continue monitor the site monitoring wells on a semi-annual basis. Robert Weimer
2/4/2013 Document, Report, or Work plan Review - other Third Quarter 2012 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.63 gallons per minute during the third quarter of 2012 (83,462 gallons). The water had 3.0 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/4/2013 Document, Report, or Work plan Review - other July 31, 2012 groundwater monitoring event. Up to 350 ug/l benzene, 36 mg/l GRO, 11 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 3 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 6.82 to 10.55 feet below ground surface. They recommend and continue monitor the passive groundwater collection system on a semi-annual basis. Robert Weimer
2/6/2013 Document, Report, or Work plan Review - other Fourth Quarter 2012 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.87 gallons per minute during the fourth quarter of 2012 (115,257 gallons). The water had 2.0 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/26/2013 Meeting or Teleconference Held Meeting with Chevron and their consultants on February 26, 2013. Chevron proposes to continue to conduct semi-annual groundwater monitoring to monitor for natural attenuation and trends, and continued monitoring of the off property collection trench. 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. Chevron to submit a work plan for decommissioning the off-property collection trench, confirmaiton soil samples, and additional on-property monitoring wells. Robert Weimer
3/12/2013 Site Visit Site visit to observe current site conditions. 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
12/11/2013 Document, Report, or Work plan Review - other First Quarter 2013 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.5 gallons per minute during the first quarter of 2013 (64,800 gallons). The water had 0.91 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
1/3/2014 Document, Report, or Work plan Review - other Second Quarter 2013 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 4 gallons per minute during the second quarter of 2013 (524,160 gallons). The water had 0.62 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/3/2014 Document, Report, or Work plan Review - other May 8, 2013 groundwater monitoring event. Up to 400 ug/l benzene, 57.6 mg/l GRO, 7.5 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 5 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 5.27 to 10.2 feet below ground surface. Samples were collect by both no-purge (Hydrasleeve) and purge (bladder pump) methods. The sampling interval for the bladder pump was not documented in the field notes. The hydrasleeve sampling was from the top of the water column. Monitoring well MW-19 had 2.7 ug/l benzene with no-purge but had 9.3 ug/l benzene with purge. Robert Weimer
2/14/2014 Document, Report, or Work plan Review - other Third Quarter 2013 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.71 gallons per minute during the third quarter of 2013 (94,060 gallons). The water had 4.0 ug/l benzene. They recommend and continue monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/27/2014 Meeting or Teleconference Held Meeting with Chevron and their consultants on 2/27/2014. They plan to continue operation of the remediation system and semi-annual groundwater monitoring and quarterly effluent sampling for the collection trenches. Chevron will be subitting a work plan for decomissioning the trenches, the installation of additional monitoring wells and characterization soil samples. 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. 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. Robert Weimer
5/19/2014 Document, Report, or Work plan Review - other September 17, 2013 groundwater monitoring event. Up to 400 ug/l benzene, 45.6 mg/l GRO, 5.9 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 5 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 4.71 to 9.72 feet below ground surface. Samples were collect by no-purge (Hydrasleeve) method. The hydrasleeve sampling was from the top of the water column. Robert Weimer
6/3/2014 Site Visit Site visit to observe current site conditions. Robert Weimer
9/22/2014 Document, Report, or Work plan Review - other Fourth Quarter 2013 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.79 gallons per minute during the fourth quarter of 2013 (104,659 gallons). The water had 3.0 ug/l benzene. They recommend and continue to monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
11/13/2014 Document, Report, or Work plan Review - other First Quarter 2014 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.26 gallons per minute during the first quarter of 2014 (33,696 gallons). The water had 1.8 ug/l benzene. They recommend and continue to monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
11/26/2014 Document, Report, or Work plan Review - other ADEC reviews and approves October 2014 Collections System Decommissioning Work Plan. The work plan proposes to decommission the two passive collection trenches and two accessible collection system sumps. Robert Weimer
12/12/2014 Document, Report, or Work plan Review - other Second Quarter 2014 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 7.93 gallons per minute during the second quarter of 2014 (1,038,513 gallons). The water had 1.3 ug/l benzene. They recommend and continue to monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
1/13/2015 Document, Report, or Work plan Review - other Third Quarter 2014 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 2.64 gallons per minute during the third quarter of 2014 (349,747 gallons). The water had 0.87 ug/l benzene. They recommend and continue to monitor the passive groundwater collection system on a quarterly basis as required by AWWU. Robert Weimer
2/12/2015 Document, Report, or Work plan Review - other On November 21, 2014 CRA submitted an Industrial Discharge Permit application to AWWU for the discharge of water generated during the planned decommissioning of collection trenches and sumps. The sample collected from sump-1 was non-detect (<0.4 ug/l) benzene, and sump-2 was 1.82 ug/l benzene. Robert Weimer
3/3/2015 Document, Report, or Work plan Review - other June 7, 2014 groundwater monitoring event. Up to 520 ug/l benzene, 60.1 mg/l GRO, 9.0 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 3 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 6.23 to 10.51 feet below ground surface. Samples were collect by purge with bladder pump and non-purge with Hydrasleeves at the top of the water column. In 5 of 6 purge monitoring well samples collected (all by MW-21) the pump intake was not collected at the soil/water interface (within the top foot) as required (they were 1.64 to 3.24 feet below soil/water interface). These results are considered biased low and can't be used for trend or comparison purposes. In addition the samples from monitoring well MW-22 and MW-23 were run with headspace in the sample jars. These results are considered biased low and can't be used for trend or comparison purposes. Robert Weimer
5/11/2015 Document, Report, or Work plan Review - other November 4, 2014 groundwater monitoring event. Up to 310 ug/l benzene, 62.9 mg/l GRO, 9.5 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 6 of the 7 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 3.33 to 14.11 feet below ground surface. Samples were collect using a bladder pump at the top of the water column after purging the monitoring wells. Robert Weimer
6/9/2015 Conceptual Site Model Submitted Conceptual Site Model identified potential soil ingestion, groundwater ingestion, indoor air inhalation, and outdoor air inhalation pathways. Robert Weimer
7/24/2015 Document, Report, or Work plan Review - other Fourth Quarter 2014 monitoring report for the passive groundwater collection trench water discharge to the sanitary sewer. The trench discharged 0.38 gallons per minute during the fourth quarter of 2014 (42,134 gallons). The water had 4.2 ug/l benzene. The system was decommissioned on December 16, 2014. Robert Weimer
11/2/2015 Document, Report, or Work plan Review - other For the 30 cubic yards of stockpiled soil generated during the decommissioning of the trench the characterization sampling for those soils would need to include BTEX, GRO, DRO analysis at two sample locations and one analytical sample to also include PAH’s and 1,2-DCA from the most likely contaminated soils based on field readings and observations. There will need to be one duplicate analytical sample collected at the PAH location for (BTEX, GRO, DRO, PAH’s, and 1,2-DCA). There will need to be a minimum of 5 field screening locations for that volume of soil. The field readings need to be collected from throughout the stockpile a minimum of 18 inches into the surface. Robert Weimer
11/13/2015 Document, Report, or Work plan Review - other The on-property and off-property groundwater collection systems were decommissioned between December 4 and 18, 2014. Approximately 30 to 40 cubic yards of contaminated soil was generated during the site work and this soil was stockpiled on site. 11.8 mg/l DRO, 0.085 mg/l GRO, and 1.4 ug/l benzene in the groundwater sample collected at Sewer-1. Robert Weimer
4/11/2016 Document, Report, or Work plan Review - other April 27, 2015 groundwater monitoring event. Up to 320 ug/l benzene, 62.0 mg/l GRO, 7.3 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 4 of the 8 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 5.98 to 10.87 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells. Robert Weimer
4/13/2016 Document, Report, or Work plan Review - other DEC is requesiting a plan on how the monitoring wells will be decommissioned. Please refer to the current DEC monitoring well guidance for what types of procedures we will need in the work plan. DEC is requesting sampling and BTEX, GRO, DRO, and PAH analysis for the next 2016 groundwater monitoring event in monitoring well MW-5. DEC is also requesting adding PAH analysis for the next 2016 groundwater monitoring event in monitoring well MW-20. DEC is requesting before redevelopment you need to submit and get approval of a contaminated site management plan. This would include dealing with excavated soil, groundwater, disposal of the existing asphalt (which has contaminated soil in it that was mixed into the asphalt), drill cuttings/installed storm water sump, and sealing storm water sump if near groundwater. Robert Weimer
5/19/2016 Document, Report, or Work plan Review - other October 23, 2015 groundwater monitoring event. Up to 71 ug/l benzene, 3.8 mg/l GRO, 2.1 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 1 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 4.53 to 9.84 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells except in MW-20 whose sample depth was not documented in the field notes. Robert Weimer
6/17/2016 Document, Report, or Work plan Review - other DEC approves request to spread the 30 cubic yard stockpile on the property. The stockpile was generated during the trench decommissioning activities. Analytical samples collected from the stockpile were below migration to groundwater cleanup levels for BTEX, GRO, DRO, PAHs, and 1,2-DCA. Robert Weimer
8/8/2016 Update or Other Action DEC receives notification from the consultant (GHD) that the stockpiled soil has not been spread yet. They intend to continue to stockpile it on the property and will notify DEC when they will spread the soil in the approved area or they will submit a new request for DEC review and approval for an alternative location. Robert Weimer
1/19/2017 Document, Report, or Work plan Review - other May 17, 2016 groundwater monitoring event. Up to 250 ug/l benzene, 41 mg/l GRO, 10 mg/l DRO, and 110 ug/l Naphthalene in the groundwater (MW-20). The other detectable PAHs were below current cleanup levels. The contamination increased from the previous monitoring event in 6 of the 8 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 5.12 to 10.52 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells. Robert Weimer
6/23/2017 Document, Report, or Work plan Review - other September 15, 2016 groundwater monitoring event. Up to 150 ug/l benzene, 17 mg/l GRO, and 7.3 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 4 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 3.33 to 14.11 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells. Robert Weimer
9/29/2017 Document, Report, or Work plan Review - other May 9, 2017 groundwater monitoring event. Up to 170 ug/l benzene, 32 mg/l GRO, and 6.6 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 4 of the 6 monitoring wells sampled. The groundwater flow direction is to the south by southeast. The depth to groundwater was 3.06 to 10.31 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells. Non-volatile samples were collected using a bailer. Robert Weimer
11/30/2017 Document, Report, or Work plan Review - other September 1, 2017 groundwater monitoring event. Up to 110 ug/l benzene, 13 mg/l GRO, and 2.9 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. The groundwater flow direction is to the southeast. The depth to groundwater was 5.44 to 10.04 feet below ground surface. Samples were collect without purging using hydrasleeve at the top of the water column of the monitoring wells. Non-volatile samples were collected using a bailer. Robert Weimer
11/30/2017 Update or Other Action DEC is requesting that future groundwater monitoring events for this site be conducted after purging with a bladder pump or in-well pump with the pump intake documented to be within the top foot of the water column at the time of the sampling. DEC is also requesting that the next monitoring event include the full 8260 VOC analysis and the 8270 PAH analysis. Based on the results of that sampling we can evaluate what to sample for in monitoring events after that. Robert Weimer
1/25/2018 Document, Report, or Work plan Review - other DEC approves request for thermal treatment at ASR of 1 drum of BTEX contaminated granular activated carbon (GAC). The GAC was used to treat purge water generated during groundwater sampling at the site. Robert Weimer
4/3/2018 Update or Other Action The first semi-annual 2018 monitoring is to include sampling after purging and to include full 8260 VOC analysis and 8270 PAH analysis. Based on the results of that sampling DEC is to evaluate what wells full VOC and PAH sampling is to continue and any reductions in groundwater monitoring at the site. Robert Weimer
1/7/2019 Document, Report, or Work plan Review - other June 7, 2018 groundwater monitoring event. Up to 160 ug/l naphthalene, 180 ug/l benzene, 46 mg/l GRO, and 4.7 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. PAH analysis by method 8270 was conducted the each of the six monitoring wells sampled. The only monitoring well over PAH cleanup levels was monitoring well MW-20 for naphthalene. The groundwater flow direction is to the southeast. The depth to groundwater was 5.11 to 10.53 feet below ground surface. Samples were collect after purging using bladder pump with the intake at the top of the water column of the monitoring wells. Missing naphthalene results from the 8260(VOC) analysis. Robert Weimer
1/16/2019 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 77986 1986 UST release. Robert Weimer
5/7/2019 Document, Report, or Work plan Review - other October 10, 2018 groundwater monitoring event. Up to 120 ug/l naphthalene, 120 ug/l benzene, 6 ug/l 1,2-DCA, 19 mg/l GRO, and 3.7 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 1 of the 6 monitoring wells sampled. PAH analysis by method 8270 was not conducted this monitoring event. The groundwater flow direction is to the southeast. The depth to groundwater was 6.06 to 10.49 feet below ground surface. Samples were collect after purging using bladder pump with the intake at the top of the water column of the monitoring wells. Missing naphthalene results from the 8260(VOC) analysis. Robert Weimer
5/14/2019 Update or Other Action DEC sent request of the missing naphthalene results from the 8260(VOC) analysis for the October 10, 2018 groundwater monitoring event. 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
12/31/2019 Long Term Monitoring Workplan or Report Review 2019 Second Semi-Annual Groundwater Monitoring event was conducted on September 26 and 27, 2019. Groundwater samples were collected from monitoring wells MW 11A, MW-19, MW-20, MW-21, MW-22 and MW-23. Samples were submitted to the laboratory for GRO, DRO, and BTEX analysis. Groundwater flow direction was to the south and depth to groundwater was 6.51 to 10.08 feet below ground surface. Toluene, ethylbenzene, and xylenes were detected in the equipment blank and trip blank samples and blank action levels were established. Rebekah Reams
1/15/2020 Document, Report, or Work plan Review - other May 11, 2019 groundwater monitoring event. Up to 110 ug/l benzene, 1,100 ug/l toluene, 760 ug/l ethylbenzene, 7,200 ug/l xylenes, 0.3 ug/l MTBE, 27 mg/l GRO, and 4.9 mg/l DRO in the groundwater. The contamination increased from the previous monitoring event in 2 of the 6 monitoring wells sampled. PAH analysis by method 8270 was not conducted this monitoring event. The groundwater flow direction is to the south by southeast. The depth to groundwater was 5.22 to 10.13 feet below ground surface. Samples were collect after purging using bladder pump. Because the pump intake was not in the top of the water column (it was around 1.5 feet) as required the results may be biased low. Only BTEX results were reported for the 8260(VOC) analysis. Robert Weimer
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
6/11/2020 Long Term Monitoring Workplan or Report Review 2020 First Semi-Annual Groundwater Monitoring event was conducted on April 15, 2020. Groundwater samples were collected from monitoring wells MW-11A, MW-19, MW-20, MW-21, MW-22 and MW-23. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 4.56 to 10.46 feet below ground surface. Exceedances of GRO, DRO, toluene, ethylbenzene, total xylenes, EDC, naphthalene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene were observed during this sampling event. Rebekah Reams
12/31/2020 Long Term Monitoring Workplan or Report Review 2020 Second Semi-Annual Groundwater Monitoring event was conducted on November 2, 2020. Groundwater samples were collected from monitoring wells MW-11A, MW-20, MW-21, MW-22, and MW-23. MW-4 and MW-19 well locks were frozen and could not be accessed. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 5.65 to 9.58 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
6/4/2021 Long Term Monitoring Workplan or Report Review 2021 First Semi-Annual Groundwater Monitoring event was conducted on April 12, 2021. Groundwater samples were collected from monitoring wells MW-11A, MW-19, MW-21, MW-22, and MW-23. The well lock at MW-20 was frozen and the well could not be opened or sampled. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 4.62 to 10.99 feet below ground surface. Rebekah Reams
12/14/2021 Long Term Monitoring Workplan or Report Review 2021 Second Semi-Annual Groundwater Monitoring event was conducted on September 29, 2021. Groundwater samples were collected from monitoring wells MW-11A, MW-19, MW-21, MW-22, and MW-23. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 5.77 to 10.10 feet below ground surface. Rebekah Reams
6/20/2022 Long Term Monitoring Workplan or Report Review 2022 First Semi-Annual Groundwater Monitoring event was conducted on April 7, 2022. Groundwater samples were collected from monitoring wells MW-11A, MW-19, MW-21, MW-22, and MW-23. Lock on MW-20 was damaged and not functioning. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 3.96 to 9.27 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
1/26/2023 Long Term Monitoring Workplan or Report Review 2022 Second Semi-Annual Groundwater Monitoring event was conducted on August 31, 2022. Groundwater samples were collected from monitoring wells MW-11A, MW-19, MW-21, MW-22, and MW-23. Samples were submitted to the laboratory for GRO, DRO, and VOC analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 5.18 to 9.80 feet below ground surface. GRO, benzene, ethylbenzene, total xylenes, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene exceeded ADEC groundwater cleanup levels in monitoring well MW-11A. Rebekah Reams
3/23/2023 Long Term Monitoring Workplan or Report Review DEC provided comments on the Groundwater Sampling Analyte Reduction Request – Groundwater Sampling Work Plan Addendum. This work plan addendum proposes to update the groundwater monitoring schedule to include analysis for GRO, DRO, BTEX, EDC, naphthalene, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene at monitoring wells MW-11A and MW-20 on a semi-annual basis. Rebekah Reams
4/19/2024 Offsite Soil or Groundwater Disposal Approved DEC approved offsite transport of 36 gallons of decontamination and purge water. Rebekah Reams
6/27/2024 Document, Report, or Work plan Review - other ADEC provided comments on the Site Investigation Work Plan. This work plan summarizes previous site investigations and proposes to advance 15 soil borings and install seven monitoring wells to evaluate soil and groundwater impacts on- and offsite. Rebekah Reams
7/12/2024 Long Term Monitoring Workplan or Report Review 2023 First Semi-Annual Groundwater Monitoring event was conducted on April 12, 2023. Groundwater samples were collected from monitoring wells MW-4, MW-11A, and MW-20. Samples were submitted to the laboratory for GRO, DRO, VOC, and lead analysis. Groundwater flow direction was to the south-southeast and depth to groundwater was 4.37 to 9.93 feet below ground surface. GRO, DRO, BTEX, EDC, naphthalene, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene exceeded ADEC groundwater cleanup levels during this sampling event. Rebekah Reams
9/24/2024 Site Visit ADEC conducted a site visit with Chevron and Arcadis personnel to observe site layout, sampling locations, and nearby features. Rebekah Reams
9/25/2024 Meeting or Teleconference Held ADEC staff met with Chevron and their consultant for an annual portfolio meeting to discuss site status, upcoming document submittals, pending reviews, and general updates for Chevron's contaminated sites throughout the state. Rebekah Reams
10/2/2024 Document, Report, or Work plan Review - other ADEC approved the Scope of Work Amendment for this site which proposes to remove SB-16 and the associated monitoring well from the sampling plan and shift the location of SB-19 and SB-20 due to safety concerns and consideration for accessible sample locations. Rebekah Reams

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State of Alaska Department of Environmental Conservation

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