Site Report: Holiday Station Store #602, formerly Williams Express Store #5002

Site Name:	Holiday Station Store #602, formerly Williams Express Store #5002
Address:	10630 Old Seward Hwy (NW corner of Seward & O'Malley), Anchorage, AK 99515
File Number:	2100.26.018
Hazard ID:	23576
Status:	Active
Staff:	Alena Voigt, 9072697556 alena.voigt@alaska.gov
Latitude:	61.124316
Longitude:	-149.864776
Horizontal Datum:	NAD83

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.

Site Chronology
IC / Closure Details
Documents
Associated Sites

Problems/Comments

A private well at Alaska Pollution Control (near HSS #602) showed 2.1 parts per million (ppm) benzene on 8/18/1987, prompting investigation into nearby sources. Investigation conducted during the removal of the USTs at this site revealed petroleum contamination in soil and groundwater. A remediation system was installed and operated for a number of years until 2015 and the site is now in long term annual monitoring. There are three distinct water-bearing zones at this site that require separate characterization, modeling, and remediation. The first, or shallow, zone is at 20-30 feet BGS and has significant contamination. The second, or intermediate zone, is 35-45 feet BGS. Contaminated groundwater has been identified. The third, or deep, zone is at 50-70 feet BGS. Flow direction varies seasonally for all three, but is generally to the northwest for the site and regionally to the west.

Action Information

Action Date	Action	Description	DEC Staff
5/5/1987	Site Visit	FI; Northern Lights Petroleum Equipment tested; UST showed no leakage.	Former Staff
6/9/1987	Site Visit	FI; Alaska Pollution Control private well is found to be contaminated; benzene > 5 ppm (MCL); city water connection not available; 200' west of Toppers #2 site (Mapco #5002).	Former Staff
6/9/1987	Underground Storage Tank Site Characterization or Assessment	PA; Mapco obtained results of Hart Crowser site assessment which demonstrated significant hydrocarbon contamination at the pump island; did not provide results to ADEC until 8/2/89. The station was assumed by Mapco in 10/87 when they bought Toppers Petroleum.	Former Staff
9/9/1987	Update or Other Action	SI; Alaska Pollution Control retained Woodward Clyde to assess soil and groundwater contamination on their site; groundwater flow from east to west; contamination from off site in the direction of Topper's (Mapco) Station #2. Alaska Pollution Control well sample 399 taken on 8/18/87 had 2.1 ppm benzene.	Former Staff
9/21/1987	Update or Other Action	SI; Hart Crowser report; groundwater in west to sw direction. Based on this report, ADEC did not request further action at the site because it indicated the major contamination source may be off site.	Former Staff
4/1/1988	Update or Other Action	SI; Parker Drilling, adjacent to Mapco site, conducts a site assessment. NORTEC site assessment report indicates the source of groundwater contamination is off site in the direction of Mapco Store #5002.	Former Staff
4/25/1988	Leaking Underground Storage Tank Release Confirmed - Petroleum	LUST Site created in CSP for source area ID 77675 ADD;	Former Staff
4/25/1988	Site Added to Database		Former Staff
4/26/1988	Leaking Underground Storage Tank Cleanup Initiated - Petroleum	LCAU; :LCAU Date changed DB conversion	Former Staff
4/26/1989	Update or Other Action	REM; Mapco gives notice to ADEC concerning removal of USTs on 4/26/89. Station shut down 6/89. B-C Excavating performed work; Hart Crowser monitored activity. 7/6/89 ADEC staff inspected site found significant contamination left in place. Piping also removed. No approved remedial action plan for this work. Contaminated soils secured on-site.	Former Staff
7/17/1989	Update or Other Action	RAPR; Hart Crowser plan to ADEC for site remediation, monitoring well installation and sampling.	Former Staff
8/24/1989	Update or Other Action	REM; Approves disposal of soils at AS&G; conditions that soils be used for asphalt production.	Former Staff
10/6/1989	Update or Other Action	REM; ADEC approves waste oil tank contaminated soils from other Mapco sites to be stored at former Mapco Express #5002; Hart Crowser; fence required; soil can remain only until 10/6/90 and will require ultimate disposal plan.	Former Staff
5/11/1990	Site Visit	FI; ADEC site inspection determines plastic membrane cover needed to be secured; recurring problem.	Former Staff
6/1/1990	Document, Report, or Work plan Review - other	MS; Hart Crowser Report containing groundwater movement and sampling results. Evidence to date indicates former Mapco Express #5002 is the source of contamination for the area (8/7/90 ADEC letter). Sample SVX-1 had 51.2 ppm benzene. Groundwater is at about 35 feet and flows towards the west.	Former Staff
8/15/1990	Update or Other Action	RAPR; Draft work plan from Hart Crowser for site remediation. On-site treatment to reduce TPH & BTEX in soil stockpiles. Groundwater treatment by air stripping.	Former Staff
9/18/1990	Update or Other Action	RAPR; RZA plan for short term vapor extraction at former Mapco Express #5002.	Former Staff
10/2/1990	Update or Other Action	REM; Disposal of stockpile SP-2 and SP-7 at Anchorage Regional Landfill.	Former Staff
10/10/1990	Update or Other Action	RAPR; RZA plan for soil remediation; focus on Stockpile 14-7 with bio-feasibility study. Three stockpiles had previously been equipped with PVC vents and seeded with fertilizer to promote volatilization and bio-remediation.	Former Staff
10/12/1990	Update or Other Action	F; Short term vapor extraction test performed by RZA.	Former Staff
11/26/1990	Update or Other Action	RAPR; Preliminary vapor extraction as-built plan for ADEC review; VE system in place and continuously operating since 11/15/90. Included plan to determine vapor extraction zone of influence.	Former Staff
12/17/1990	Update or Other Action	F; RZA Inc. sends vapor extraction operation report to DEC for 1st week of operation. Free product layer of approximately .44' was confirmed at soil vapor extraction well SVX-1 11/29/90 & .01' at well HC-2.	Former Staff
4/12/1991	Institutional Control Record Established	Date of Compliance order by Consent.	Keather McLoone
5/1/1992	Update or Other Action	LCAR; Soil vapor extraction system is operating. Groundwater treatment system is being revamped due to failure to meet waste discharge permit standards for lead and benzene. Current water recovery plans call for pumping 2 gallons per minute from one recovery well. Letter responding to Mapco requested an updated corrective action plan by not later than June 15, 1992. Additional site assessment work has been conducted at Alaska Pollution Control, located to the west of the site. Results are pending. three water wells at Alaska Pollution Control are in the process of being abandoned. Requested additional ground water investigation to define full extent and location of ground water contaminant plume to the north-northwest of the site.	Former Staff
6/1/1992	Update or Other Action	CAPR; Letter sent to Shannon and Wilson regarding relocating soils from MAPCO #1 to MAPCO #2 for VES treatment. DEC requested some soil cell design criteria which were subsequently met by MAPCO. Soils were successfully treated and taken off site later in the summer to be used as upland fill for a new MAPCO.	Former Staff
6/29/1992	Update or Other Action	CAPR; Workplan received 19 May 1992 for a new Class C well on Alaska Pollution Control Property (previous well was affected by pollution from MAPCO 2). Sent letter back to RZA-RCRA requesting more information and a meeting.	Former Staff
7/7/1992	Update or Other Action	Proposal of 6/22/92 for Groundwater Remediation System reviewed. Approval was given to start remediation. MAPCO must publish public notice of local contamination. Text of public notice approved 7/8/92.	Former Staff
7/25/1994	Update or Other Action	LCAR; Groundwater monitoring and VES	Former Staff
10/1/1994	Update or Other Action	COMR; Complaint received.	Former Staff
10/15/1994	Site Visit	COMI; Complaint investigated.	Former Staff
10/20/1994	Update or Other Action	LCAR; Performed a Corrective Action Report review.	Former Staff
11/21/1994	Update or Other Action	LCAR; Review monitoring well reports.	Former Staff
3/18/1995	Update or Other Action	LCAR; Reviewed quarterly reports.	Former Staff
7/15/1995	Update or Other Action	LCAR; Reviewed quarterly monitor well report required by COBC.	Former Staff
7/25/1995	Update or Other Action	MEET; Met with RP to discuss status of site. (action code was CAPR)	Former Staff
8/15/1995	Update or Other Action	LCAR; Reviewed a report on impacted area wells.	Former Staff
9/15/1995	Update or Other Action	CAPR; Reviewed files.	Former Staff
11/20/1997	Update or Other Action	ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: MAPCO EXPRESS	Former Staff
11/11/2000	Update or Other Action	Received Historical Site Summary	Lynne Bush
2/5/2001	Underground Storage Tank Site Characterization or Assessment	Approved MW decommissioning plan	Lynne Bush
3/14/2001	Update or Other Action	Put copy of potential off-site impact study from Parker Drilling (L55.25) in this file.	Lynne Bush
9/17/2001	Update or Other Action	Changed ADEC Project Manager from Bush to Wiegers	Cynthia Pring-Ham
6/17/2002	Update or Other Action	Corrected address to 10630 Old Seward Highway (was 10800)	Janice Wiegers
11/21/2002	Update or Other Action	Fall monitoring report submitted. Product observed in MW-22 (property north of Williams site). 1 gallon of product removed with slow recharge. Apparent increase in benzene observed downgradient of MW-22. Highest benzene concentration detected on Williams property in MW-28 (12,000 ppb).	Janice Wiegers
3/11/2003	Update or Other Action	Per J. Wiegers, changed file number from L30.02 to 2100.26.018	Wendy Uzzell
5/1/2003	Update or Other Action	Monitoring well installation and drinking water decommissioning report submitted. Drinking water well decommissioned on property to north. Monitoring wells MW-29 through MW-31B installed and sampled. MW-31A installed in deeper water bearing unit (35-45 ft bgs). Maximum benzene (24,000 ppb) and GRO (120 ppm) detected in MW-31A. Soil sample results indicated soil contamination present in smear zone: highest historical concentrations still detected at MW-22 (location of free product).	Janice Wiegers
6/19/2003	Document, Report, or Work plan Review - other	Spring remediation and monitoring report submitted. Hydrocarbon recovery rates have remained low since 2002. Benzene has not been detected in the exhaust since 2000. The highest groundwater concentrations were found in the deep well MW-31A (benzene at 21,000 ppb) approximately 20 feet below the shallow wells. Benzene was not detected in the associated shallow groundwater well (MW-31B). This well is located near and downgradient of former UST arrays on the adjacent property. Product was present in MW-22.	Janice Wiegers
11/14/2003	Document, Report, or Work plan Review - other	Remediation and groundwater monitoring report submitted. Product present in off-site wells. The highest dissolved concentrations found on-site were in MW-28 (16,000 ppb benzene). The deep well (MW-31A) contained the highest off-site dissolved concentrations, but contaminants were not detected in shallow wells around the deep well. Vertical migration or migration at depth in the aquifer needs further investigation.	Janice Wiegers
3/19/2004	Document, Report, or Work plan Review - other	Workplan for lead scavenger sampling approved. EDB will be analyzed with EPA method 8260. Further evaluation with a method with a lower detection limit may be conducted in future sampling events.	Janice Wiegers
6/17/2004	Update or Other Action	File review to approve cost recovery invoice.	Lynne Bush
7/7/2004	Update or Other Action	On 07 July 2004, Bush met with Holiday representative Bruce Anthony; Williams Express representative Terrie Blackburn; and Shannon & Wilson representatives Matt Hemry, Ben Heaver, and Tim Terry. The topic of discussions was plans for future activities at all former Williams Express Stations.	Lynne Bush
9/8/2004	Update or Other Action	Holiday will be assuming responsibility for investigative and remediation activities at all former Williams Express Stores, but legal responsibility is divided by store. Holiday has renumbered their stores as: 5001=601; 5002=602; 5005=605; 5005=605; 5006=606; 5007=607; 5008=608; 5010=610; 5014=614; 5016=616; 5018=618; 5024=624; 5025=625; 5030=630; 5031=631; 5050=650. While Holiday will oversee the work at the former Williams’ stations, these sites remain the responsibility of Williams. The numbers of these sites remain the same: 5003; 5004; 5009; 5012; 5015; 5017; 5021; and 5034.	Lynne Bush
9/27/2004	Update or Other Action	Approved delay for bi-annual reporting to include more recent remediation monitoring data. The new target date is early December.	Lynne Bush
10/1/2004	Update or Other Action	A decision was made in 2004 by Williams and Holiday to sample selected sites for lead scavengers. The purpose of this investigation is to determine whether or not lead scavenger compounds such as ethylene dibromide and ethylene dichloride are viable constituents of concern. This site was included for lead scavenging investigation based on risk ranking. Risk rank was determined by the presence of wells and potential receptors, known period of leaded gasoline sales at this site, the known presence/absence of Pb scavengers, and the general level of hydrocarbon concentrations. The first event for chosen high risk sites occurred in Spring 2004. Station 2 is the only site where lead scavenger analysis exceeded ADEC target cleanup levels. Monitoring Well 27 had an ethylene dichloride level of 0.202ppm.	Lynne Bush
10/1/2004	Update or Other Action	Future plans for this site include continued monitoring, continued operation of the remediaiton system, evaluation of the costs for site remediation operation, evaluation of off-site migration, evaluation of the three aquifers indentified at this site for migration and contaminant conscentration parameters, establishment of an off-site point of compliance, possible assessment of gradient and plume extent in each aquifer, and installation of additional monitoring wells. A work plan should be submitted prior to the end of 2004.	Lynne Bush
10/20/2004	Update or Other Action	The Soil Vapor Extraction system operation schedule for this site is continuous and the sampling frequency is quarterly. The Air Injection System operation schedule for this site is continuous and the sampling frequency is quarterly. The groundwater sampling frequency remains bi-annually in March and September. Free product is present and being monitored at this site on a monthly basis. Groundwater flow is to the west as of April 2004.	Lynne Bush
1/11/2005	Update or Other Action	Work plan to install two new monitoring wells received.	Lynne Bush
1/12/2005	Update or Other Action	Received work plan for installation of two new monitoring wells in the vicinity of MW-16.	Lynne Bush
1/18/2005	Document, Report, or Work plan Review - other	Reviewed semi-annual report. General groundwater flow direction is to the west, but on-site, the direction is west-northwest. The vapor extraction system recovers 4.9 pounds per day.	Lynne Bush
1/18/2005	Document, Report, or Work plan Review - other	The vapor extraction blower should be upgraded, the system should be operated continuously, product thickness in wells with product should be measured monthly, monitoring well MW-19 should be decommissioned, and characterization of the intermediate and deep aquifers should be planned.	Lynne Bush
1/18/2005	Update or Other Action	E-mail request for work plan to accomplish goals determined recently.	Lynne Bush
1/18/2005	Update or Other Action	Work plan approval to install two new wells in the vicinity of monitoring well MW-16 approved via e-mail and fax. These wells will assess the intermediate and deep aquifers.	Lynne Bush
3/15/2006	Update or Other Action	Approval of July 5, 2005 work plan. 1. Suspend monthly product monitoring, dependent upon observations in future groundwater monitoring events; 2. Conduct annual sampling collection for MW-18, MW-20, MW-26, MW-21 and MW-31-A; 3. Suspend sample collection for MW-11, MW-13, and MWP-3; 4. Conduct semi-annual sample collection for the remaining viable wells; 5. Decommission MW-19; 6. Provide a summary report of activities with the annual report.	Lynne Bush
5/9/2006	Update or Other Action	Project management transferred from Bush to O'Connell.	Aggie Blandford
5/11/2006	Document, Report, or Work plan Review - other	Rec'd April to Dec. 2005 Monitoring Report. VES Blower replaced, April 2005. Free product measured in MW22, 10/12 months in 2005. Benzene exceeded Table C in MW-15, MW-17, MW-21, MW-22, MW-23, MW-26, MW-27, MW-28, MW-29, MW-30, MW-31a, and MW-32 during one or more 2005 sampling events. Next monitoring event in spring 2006.	Bill O'Connell
3/16/2007	Exposure Tracking Model Ranking		Former Staff
6/12/2007	Document, Report, or Work plan Review - other	Received 2006 Monitoring report. QA/QC conducted. 18 wells were sampled in spring 2006 and 13 in the fall. 0.15 feet of product was encountered in MW-22 during the spring event. Groundwater contamination above Table C cleanup levels is present in the upper two of three water bearing zones at the site and off site to the northwest. 2006 sampling results are generally consistent with historic trends.	Bill O'Connell
7/17/2008	Document, Report, or Work plan Review - other	Receipt of 2007 report electronically. Review included laboratory review checklist. S&W reports that Holiday may use ISOC and may shutoff and remove VEW-2 and VEW-3. The VES will continue to operate.	Keather McLoone
9/5/2008	Update or Other Action	ADEC approved dropping MW-12 from the program because it has not been found during the two 2007 events and was ND for 3 events in a row. During 9/24/08 meeting there was some discussion about whether the well was missing or not. Site visit to be conducted later in September will include an attempt to clarify the status of this well.	Keather McLoone
6/5/2009	Document, Report, or Work plan Review - other	Review of Oxygen Releasing Compound Pilot Study Work Plan. Focused study to include MW-28, in which a series of ORC socks will be installed. Upgradient well MW-13 and downgradient well MW-30 will also be included in the study. Pre-ORC installation, July, and September parameters will include GRO/BTEX, DO, pH, temperature, redox potential to evaluate the effectiveness. Heterotrophic plate count and ferric/ferrous iron will also be measured pre-ORC installation and in September. DEC has requested to be notified when pre-installation measurements and soc installation take place.	Keather McLoone
7/23/2009	Document, Report, or Work plan Review - other	Review of January to December 2008 Remediation System and Groundwater Monitoring report submitted 7/1/09. The VES was part of initial remedial efforts at this site (1990-1995) and along with a P&T. In 1995 the VES was modified. During 2008, the VES generally operated on a continuous basis with the dilution valve and the seven VES lines for an estimated 344 days. System monitoring was conducted on a monthly basis and analytical samples were to be collected quarterly. Individual lines typically have higher concentrations than the combined exhaust, likely due to the dilution valve. The AIS operated on a continuous basis with the bleed valve closed and cycles between the left and right banks with each bank operating for a 12-hour time period. Monitoring of this system consisted of recording blower pressure and measuring flow in the individual lines. The average flow rates of the lines were generally less than the target range and exhibited variability thru the monitoring period. Previous efforts to increase pressure have been generally unsuccessful. Groundwater samples were collected from seven wells in April 2008 and from 20 wells in September 2008. Samples for natural attenuation parameters were collected from MW-27, MW-28, and MW-30 during September's event. These analyses were also performed on water collected from MWP-3 and MW-13. Review included laboratory review checklists.	Keather McLoone
3/18/2010	Document, Report, or Work plan Review - other	Receipt and initial review of Oxygen Release Compound Pilot Study report. Results of study are inconclusive and other options will be discussed. The effect of the ORC soc was deemed to be localized to the application well and not produce a "rapid decrease in hydrocarbon concentrations at the site".	Keather McLoone
3/24/2010	Update or Other Action	Phone conversation with S&W to discuss the possibility of attempting an "enhanced fluid extraction" technique at MW-28 this upcoming season as a followup to the Pilot Study done on the ORC socs.	Keather McLoone
4/23/2010	Update or Other Action	confirmed with AWWU that this location is on city water - unclear if the private well that is listed on the Anchorage Live website is one that has been decommissioned.	Keather McLoone
4/29/2010	Document, Report, or Work plan Review - other	Review of Source Area Soil-Gas and Groundwater Evaculation Work Plan received via email on 4/20/10. Signed acceptance page was returned via email on today's date with a request that DEC be notified for the first treatment event so that a site visit can be conducted.	Keather McLoone
5/5/2010	Site Visit	Site visits to observe groundwater sampling and vacuum truck extraction. Shannon & Wilson communicated via email that approximately 200 gallons of groundwater were removed during the several hours that the vac truck was hooked up to the top of the well casing.	Keather McLoone
2/24/2011	Document, Report, or Work plan Review - other	Reviewed Source Area Soil Gas and Groundwater Evacuation Report, received February 15, 2011. A vacuum truck was used on May 5, June 8, and July 7 to remove soil gas and groundwater from MW-28. Groundwater samples were collected before and after the first and last of these purge events. This well was also sampled in September as part of the annual sampling effort. On May 5, the ORC socks were removed. A vacuum of about 12 psi was applied on May 5 for 5 1/2 hours removing about 283 gallons of liquid. For this and each of the other two events, groundwater was below the top of the well screen, so it is likely that any soil gas or groundwater was purged. The other two events involved 8 hours of applied vacuum. About 270 gallons were removed in June and about 310 gallons in July. The report concludes that the effectiveness of this approach could not be measured. Review included laboratory data review checklists.	Keather McLoone
6/6/2011	Document, Report, or Work plan Review - other	Received January-December 2010 Remediation System and Groundwater Monitoring report. AIS was not operating between May 2009 and March 2010, then operated for 5 months before being turned off and found to be inoperational.	Keather McLoone
4/30/2012	Document, Report, or Work plan Review - other	Received January-December 2011 Remediation System and Groundwater Monitoring Report. Review included laboratory data checklist. Seventeen wells were sampled in September. The VES operated 358 days last year. The AIS has not operated since September 2010, despite last year's comment letter.	Keather McLoone
9/27/2012	Meeting or Teleconference Held	Conducted annual fall meeting with Holiday & their consultant (S&W). Discussed potential contaminant spread from HSS 602 onto First Student property (Operated by Parker Drilling) and the need for remediation. Holiday contends that contamination on First Student property is not the result of their historic releases (or is largely the result of a co-mingled plume). Data analysis will be conducted, and another meeting will occur in November to address this claim and decide upon a future course of action. ADEC also requested 1) a spring sampling event to be conducted in Spring 2013, if possible, 2) Documentation of any agreed modifications to the COBC agreements/requirements, 3) response on feasibility of adding nodes to VEAIS system to address high contaminant levels on First Student property, 4) Alternative strategies for addressing high contaminant levels if adding nodes isn't feasible, 5) Routine measurement of product thickness in wells. Item #s 3 & 4 will be put on hold until after the follow-up meeting in November. Also discussed HSS #606 and 630.	Richard Bernhardt
12/7/2012	Meeting or Teleconference Held	Project manager participated in a follow-up RP meeting with Holiday and their consultants from S&W where I summarized the 25 year case history for this site, focusing on evidence of source areas (or lack thereof) on both Holiday’s property and their neighbor to the north (Parker Drilling… now First Student). I outlined a path forward that involves active remediation with generalized measures of success. The plume doesn’t appear to be migrating, but retains free product and significantly elevated hydrocarbon concentrations that are beyond the radius of influence of the existing remediation system, which now only serves as a vapor extraction system. Holiday is interested in progressing toward site closure and proposed transitioning into Monitored Natural Attenuation (MNA) as a remediation strategy. However, this is not currently a viable option based on an inconclusive/ineffective ORC pilot study and contaminant concentration trends over the site’s extended history. Optimizing the methods from S&W’s Soil Gas and Groundwater Evacuation Pilot Study and treating the plume in its central hotspot (area of highest concentration) appears to be the most promising means of reducing the plume and progressing to a state where Enhanced Natural Attenuation (ENA) or MNA may become viable options. ADEC also proposed that the current remediation system be turned off in exchange for optimizing and implementing the SG&GWE study in the heart of the plume on Holiday’s and Parker’s property. ADEC will proceed by developing achievable performance metrics, endpoints for the SG&GWE approach, and strategies to allow for a transition to ENA and/or MNA with long-term monitoring. Meanwhile, Holiday will consider whether they would like to explore the SG&GWE approach with the understanding that a remediation system must remain in place, alternative remediation options are becoming limited, and the current vapor extraction system has outlived its usefulness without having significant upgrades.	Richard Bernhardt
4/29/2013	Document, Report, or Work plan Review - other	Reviewed Annual Report for Holiday 602. The VES portion of the remediation system operated normally in 2012, the AIS has not operated since September 2012. Four vapor samples were collected from the VES in 2012 and did not contain detectable concentrations of contaminants. Groundwater samples were collected from 17 wells during the annual monitoring event in September 2012. The groundwater elevation was approximately 3 feet higher than in September 2011, likely due to above average precipitation in the Anchorage area during this month. This resulted in generally lower concentrations of hydrocarbons detected in wells on site, and generally higher concentrations in downgradient wells. The highest concentration of benzene was detected in well MW-23 at 0.285 mg/l. MW-28, which typically contains the highest concentrations of benzene, had benzene at 0.00348 mg/l. The report indicates that the screened interval at monitoring wells MW-14, -16, -17, -18, -22, -23, -28, -29, -32, and -33 was below the static water level in these wells indicating the data should be considered as screening level data and not representative of aquifer conditions. Generally monitoring data indicate the plume is stable.	Bill O'Connell
7/8/2013	Document, Report, or Work plan Review - other	Reviewed work plan for the decommissioning of MW-31A and the installation of a replacement well named MW-34, which will be installed approximately 5 feet to the east of the former MW-31A. Soil samples will be collected and the well will be screened below the water table at 35-45 feet bgs. The well will then be purged and sampled.	Bill O'Connell
12/2/2013	Document, Report, or Work plan Review - other	Reviewed Monitoring Well Replacement Report for Holiday 602. Monitoring well MW-31A was decommissioned in accordance with ADEC guidance and monitoring well MW-34 was installed approximately 5 feet to the east. One soil sample was collected where groundwater was initially encountered at 21.5 to 22 feet bgs and did not contain detectable concentrations of contaminants. The well was completed to 45 feet bgs to match the former depth of MW-31A. Drill cutting from below the water table exhibited sheen and hydrocarbon odor. The well was sampled during the annual monitoring event and the groundwater data will be reported at a later date.	Bill O'Connell
12/2/2013	Document, Report, or Work plan Review - other	Reviewed Monitoring Well Replacement Report for Holiday 602. Monitoring well MW-31A was decommissioned in accordance with ADEC guidance and monitoring well MW-34 was installed approximately 5 feet to the east. One soil sample was collected where groundwater was initially encountered at 21.5 to 22 feet bgs and did not contain detectable concentrations of contaminants. The well was completed to 45 feet bgs to match the former depth of MW-31A. Drill cuttings from below the water table exhibited sheen and hydrocarbon odor. The well was sampled during the annual monitoring event and the groundwater data will be reported at a later date.	Bill O'Connell
4/11/2014	Document, Report, or Work plan Review - other	Reviewed 2013 Remediation System and Monitoring Report for HSS 602. The remediation system consisted of an air injection system (AIS) and a vapor extraction system (VES). The AIS has not operated since 2010. The VES has experienced diminishing returns and vapor samples collected in July and October 2013 did not contain detectable concentrations of contaminants. The report recommends switching to pulse operation rather than continuous operation. Groundwater samples were collected from 18 monitoring wells in October 2013. Samples collected during this monitoring event were collected following purging of the monitoring wells as opposed to samples that were collected in previous years using the no-purge method. Free product was not observed in any of the monitoring wells sampled in 2013. Groundwater at the site appears to be present at three intervals, shallow, intermediate and deep and groundwater elevations have been increasing over recent years. Contaminant concentrations in the shallow plume are somewhat variable however the plume appears stable overall. Benzene was detected up to 3.38 mg/l in MW-23 in the shallow plume. Monitoring well MW-31A in the intermediate plume has shown the highest levels of contamination at the site, with benzene detected at 16.1 mg/l. The leading edge of this plume is monitored in MW-32 which has shown increasing concentrations in recent sampling events, though lower than historical concentrations detected in 2005. The deep plume is delineated by sentry well MW-33 which did not contain contaminants above cleanup levels in 2013. Contaminant concentrations are elevated above cleanup levels both on and off site but exhibit long term decreasing trends.	Bill O'Connell
5/22/2014	Document, Report, or Work plan Review - other	Reviewed Groundwater Sampling Program Modification for HSS 602. The objective of the modified plan is to focus on plume boundary/sentinel wells and only sample source area wells every other year. Groundwater was sampled quarterly from 1993 to 2008, then annually from 2008 until 2014. In 2013, groundwater samples were collected from 18 wells. Because contaminant trends in groundwater are well established, the modified plan proposes sampling 9 wells on an annual basis and nine wells on a biennial basis. Four wells that are not part of the current sampling program, MWP-3, MW-11, MW-12, and MW-13 will be decommissioned. Monitoring wells that will be sampled on an annual basis include MW-21, MW-27, MW-30, MW-32, MW-33, MW-17, MW-18, MW-20 and MW-14. Wells moved to biennial sampling include MW-15, MW-16, MW-26, MW-31B, MW-22, MW-23, MW-28, MW-29 and MW-34.	Bill O'Connell
6/27/2014	Document, Report, or Work plan Review - other	Monitoring wells MWP-3, MW-11, MW-1, and MW-13 were decommissioned in accordance with ADEC guidance. These wells were removed from the monitoring program between 2005 and 2008.	Bill O'Connell
5/8/2015	Update or Other Action	VES system turned off for rebound test.	Bill O'Connell
5/18/2015	Document, Report, or Work plan Review - other	Reviewed 2014 Remediation System and Groundwater Monitoring Report for HSS #602. The vapor extraction system worked on a pulse schedule in 2014 consisting of two, 12-hour operating periods per week. A sample of the system exhaust did not contain detectable concentrations of contaminants and the system was shut off in May 2015 for a rebound test. Groundwater samples were collected from 16 monitoring wells, which are completed in the three different water bearing zones present at the site. Results from the shallow zone indicate long term decreasing contaminant trends and a delineated plume. Results from the intermediate zone indicate the highest contaminant levels at the site in well MW-34, with benzene detected at 18.4 mg/l. The leading edge of the plume in the intermediate zone is in the vicinity of MW-32, which has contained increasing concentrations of benzene since 2010. The deep plume appears stable and delineated.	Bill O'Connell
3/8/2016	Document, Report, or Work plan Review - other	Reviewed 2015 Remediation System and Groundwater Monitoring Report for Holiday 602. The vapor extraction system operated for 420 hours in 2015, 12 hours per day on Mondays and Fridays only. Vapor samples collected from the VES system did not contain detectable concentrations of contaminants. The air injection system has not operated since 2010. Groundwater samples were collected from 16 monitoring wells in September 2015. MW-16 was damaged and could not be sampled. Groundwater samples continue to show elevated levels of benzene both on and off the source property with detections up to 19.1 mg/l in MW-34 north of the source property.	Bill O'Connell
4/20/2016	Document, Report, or Work plan Review - other	Reviewed Work Plan for Remediation System Decommissioning at Holiday 602. The vapor extraction/air injection (VEAIS) was installed in 1997. The AIS was shut down in 2010 and was not restarted. The VES was shut down in May 2015 after vapor sampling indicated limited effectiveness of the system. The work plan indicates the above ground components of the system will be removed from the site. Below grade components of the system will be filled with concrete or bentonite then patched to match the surrounding surface.	Bill O'Connell
1/10/2017	Document, Report, or Work plan Review - other	Reviewed remediation system decommissioning report for HSS 602. The combination vapor extraction/air injection system was installed in 1997. The AIS was shut down in 2010 and the VES was shut down in 2015. The remaining VES wells were cut off and filled with bentonite. Below grade lines were filled with bentonite, cut off and capped below ground surface and left in place. Above grade equipment was removed from the property.	Bill O'Connell
4/12/2017	Document, Report, or Work plan Review - other	Reviewed 2016 Annual Groundwater Monitoring Report for HSS 602. Samples were collected from 15 monitoring wells in September 2016. MW-16 and MW-22 had damaged well casings and could not be sampled, MW-26 is presumed destroyed. Petroleum contamination remains in groundwater above DEC cleanup levels both onsite and offsite at the two properties to the north and is present in the shallow, intermediate, and deep water bearing zones. Contaminant concentrations have varied overt time and well MW-28 has had increasing benzene concentrations over the last 4 years, however this appears somewhat related to groundwater elevations, which have also varied by as much as 5 feet or more in some wells over the same time period. Report recommendations include decommissioning of MW-16 and repairing MW-22.	Bill O'Connell
9/22/2017	Update or Other Action	Damaged monitoring well MW-16 approved for decommissioning	Bill O'Connell
12/26/2017	Document, Report, or Work plan Review - other	Reviewed 2017 groundwater monitoring report for Holiday Station Store 602. Groundwater samples were collected from 15 monitoring wells in October 2017. Three wells could not be sampled: MW-22 is damaged, MW-26 could not be located and MW-34 contained 0.2 feet of free product. Groundwater is present in three distinct water bearing zones and remains contaminated above cleanup levels at the source property and on the two adjacent properties to the north.	Bill O'Connell
6/10/2019	Document, Report, or Work plan Review - other	October 12-13, 2017 groundwater monitoring event. Up to 4,090 ug/l benzene in the monitoring wells sampled this monitoring event. Concentrations increased in 6 of the 15 monitoring wells sampled. Free product of 0.2 feet was measured in monitoring well MW-34 this monitoring event. Depth to groundwater was 15.08 to 26.15 feet below ground surface. Groundwater historically flows to the northwest. During this monitoring event the monitoring wells were purged prior to sampling. The groundwater samples were collected using a bailer except for monitoring wells MW-32, MW-33, MW-34, and MW-35 that were collected using a submersible pump with the pump intake in the middle of the 10 foot well screen with a top of well screen that is submerged under the groundwater surface to assess contamination in the deeper aquifer at the site. Because the volatile samples were collected using a bailer they are considered biased low due to loss of volatiles using that method. MW-22 was not sampled due to bentonite in the monitoring well. Monitoring well MW-26 could not be located. Monitoring well MW-17, MW-18, MW-23, and MW-29 had a submerged well screens (groundwater 6.37', 9.62', 0.08', and 1.4' above screened interval respectively) the results in these monitoring wells may be biased low.	Robert Weimer
6/11/2019	Document, Report, or Work plan Review - other	September 17-19, 2018 groundwater monitoring event. Up to 16,300 ug/l benzene, 19,100 ug/l toluene, 1,960 ug/l ethylbenzne, and 3,900 ug/l xylenes in the monitoring wells sampled this monitoring event (the highest concentration was in monitoring well MW-34 which is in the deeper aquifer). Concentrations increased in 5 of the 13 monitoring wells sampled. No measurable free product this monitoring event. Depth to groundwater was 17.14 to 26.97 feet below ground surface. Groundwater historically flows to the northwest. During this monitoring event the monitoring wells were purged prior to sampling. The groundwater samples were collected using a bailer except for monitoring wells MW-32, MW-33, MW-34, and MW-35 that were collected using a submersible pump with the pump intake in the middle of the 10 foot well screen with a top of well screen that is submerged under the groundwater surface to assess contamination in the deeper aquifer at the site. Because the volatile samples were collected using a bailer they are considered biased low due to loss of volatiles using that method. MW-22 was not sampled due to bentonite in the monitoring well. Monitoring wells MW-20 and MW-26 could not be located. MW-18 was not sampled because it was damaged (it also had a submerged well screen, 7.56' above). Monitoring well MW-17 had a submerged well screen (water 4.7' above) the results in this monitoring well may be biased low.	Robert Weimer
6/17/2019	Meeting or Teleconference Held	Meeting with Holiday and their consultant (Shannon & Wilson). In 2019 they are to conduct further release investigation including soil sampling from borings, continue ground water monitoring, switch to using an in-well positive displacement pump (instead of bailers due to the loss of volatiles) with the intake in the top foot of the water column/screened interval. They proposed to decommission MW-22, suspend sampling of MW-26, repair/replace MW-30, install a monitoring well in the "intermediate zone" north of MW-32 and another east of MW-18, and install a monitoring well in the "shallow zone" north of MW-14.	Robert Weimer
12/28/2020	Site Characterization Workplan Approved	The CSP approves the Work Plan for Additional Site Characterization Activities and Annual Groundwater Sampling prepared by Shannon & Wilson, Inc. on December 28, 2020.	Randy Guintu
12/28/2020	Site Characterization Workplan Approved	The CSP approves the Work Plan for Additional Site Characterization Activities and Annual Groundwater Sampling prepared by Shannon & Wilson, Inc. on December 28, 2020.	Randy Guintu
11/12/2021	Offsite Soil or Groundwater Disposal Approved	The ADEC approved for one 55-gallon drum of monitoring well purge water, contaminated with GRO, VOCs, and PAHs, to be shipped and disposed of at the US Ecology facility in Anchorage. The ADEC also approved for one 55-gallon drum of development waster with all contaminants below ADEC cleanup levels (CULs) to be discharged to the property, and one 55-gallon drum of excavation soil, with contaminants below ADEC CULs, to be landspread on the property.	Flannery Ballard
2/21/2023	Site Characterization Report Approved	ADEC issued approval letter for "Release Investigation and Groundwater Sampling Activities, Holiday Station Store No. 602”, dated May 2022. The 2021 groundwater sample data continue to indicate elevated dissolved-phase hydrocarbon concentrations in both on-Property and off-Property monitoring wells. Concentration gradients and distribution patterns remain consistent with the presence of discrete on-Property and off-Property source areas. The data also indicate different plume characteristics at discrete depth intervals. The plume in the “shallow” zone has historically been defined, with the leading edge in the approximate vicinity of Well MW-15 and former Well MW-16. The leading edge of the plume of the ‘intermediate’ zone located in the vicinity of Well MW-32. With the exception of the October 2007 sample, benzene, toluene, ethylbenzene, and xylenes (BTEX) concentrations in samples from Well MW-33, which is screened in the “deep” zone, have either been non-detect or less than ADEC Table C cleanup levels. Groundwater flow direction is to the west/northwest.	Alena Voigt
4/17/2023	Meeting or Teleconference Held	Teleconference with RP representative Hal Hatfield, S&W Environmental consultant Dan McMahon, EPM1 LKB, and PM AV regarding a path towards site closure.	Alena Voigt
5/31/2023	Site Characterization Workplan Approved	The ADEC CSP reviewed the “Work Plan for Additional Site Characterization and Groundwater Monitoring Activities, Holiday Station Store No. 602” dated May 17, 2023, from Shannon & Wilson, Inc. The project activities will consist of advancing three soil borings, installing three groundwater monitoring wells, collecting soil and groundwater samples, managing investigation-derived waste (IDW), and preparing a summary report.	Alena Voigt
9/1/2023	Site Characterization Workplan Approved	The ADEC CSP reviewed the “Work Plan for Decommissioning One Monitoring Well; 10560 Old Seward Highway, Anchorage, Alaska” dated September 1, 2023, from BGES, INC. The scope of work includes decommissioning one monitoring well (MW-23), stockpile soil sampling, and preparation of a summary report.	Alena Voigt
11/8/2023	Site Characterization Report Approved	The CSP reviewed the “Monitoring Well Decommissioning & Stockpile Sampling; 10560 Old Seward Highway Letter Report,” dated October 30, 2023, from BGES, INC. (BGES). The report documents decommissioning one monitoring well, identified as MW-23, and stockpile soil sampling. Stockpile soil approved to be spread on-site.	Alena Voigt

Action Date

Action

Description

DEC Staff

5/5/1987

Site Visit

FI; Northern Lights Petroleum Equipment tested; UST showed no leakage.

Former Staff

6/9/1987

Site Visit

FI; Alaska Pollution Control private well is found to be contaminated; benzene > 5 ppm (MCL); city water connection not available; 200' west of Toppers #2 site (Mapco #5002).

Former Staff

6/9/1987

Underground Storage Tank Site Characterization or Assessment

PA; Mapco obtained results of Hart Crowser site assessment which demonstrated significant hydrocarbon contamination at the pump island; did not provide results to ADEC until 8/2/89. The station was assumed by Mapco in 10/87 when they bought Toppers Petroleum.

Former Staff

9/9/1987

Update or Other Action

SI; Alaska Pollution Control retained Woodward Clyde to assess soil and groundwater contamination on their site; groundwater flow from east to west; contamination from off site in the direction of Topper's (Mapco) Station #2. Alaska Pollution Control well sample 399 taken on 8/18/87 had 2.1 ppm benzene.

Former Staff

9/21/1987

Update or Other Action

SI; Hart Crowser report; groundwater in west to sw direction. Based on this report, ADEC did not request further action at the site because it indicated the major contamination source may be off site.

Former Staff

4/1/1988

Update or Other Action

SI; Parker Drilling, adjacent to Mapco site, conducts a site assessment. NORTEC site assessment report indicates the source of groundwater contamination is off site in the direction of Mapco Store #5002.

Former Staff

4/25/1988

Leaking Underground Storage Tank Release Confirmed - Petroleum

LUST Site created in CSP for source area ID 77675 ADD;

Former Staff

4/25/1988

Site Added to Database

Former Staff

4/26/1988

Leaking Underground Storage Tank Cleanup Initiated - Petroleum

LCAU; :LCAU Date changed DB conversion

Former Staff

4/26/1989

Update or Other Action

REM; Mapco gives notice to ADEC concerning removal of USTs on 4/26/89. Station shut down 6/89. B-C Excavating performed work; Hart Crowser monitored activity. 7/6/89 ADEC staff inspected site found significant contamination left in place. Piping also removed. No approved remedial action plan for this work. Contaminated soils secured on-site.

Former Staff

7/17/1989

Update or Other Action

RAPR; Hart Crowser plan to ADEC for site remediation, monitoring well installation and sampling.

Former Staff

8/24/1989

Update or Other Action

REM; Approves disposal of soils at AS&G; conditions that soils be used for asphalt production.

Former Staff

10/6/1989

Update or Other Action

REM; ADEC approves waste oil tank contaminated soils from other Mapco sites to be stored at former Mapco Express #5002; Hart Crowser; fence required; soil can remain only until 10/6/90 and will require ultimate disposal plan.

Former Staff

5/11/1990

Site Visit

FI; ADEC site inspection determines plastic membrane cover needed to be secured; recurring problem.

Former Staff

6/1/1990

Document, Report, or Work plan Review - other

MS; Hart Crowser Report containing groundwater movement and sampling results. Evidence to date indicates former Mapco Express #5002 is the source of contamination for the area (8/7/90 ADEC letter). Sample SVX-1 had 51.2 ppm benzene. Groundwater is at about 35 feet and flows towards the west.

Former Staff

8/15/1990

Update or Other Action

RAPR; Draft work plan from Hart Crowser for site remediation. On-site treatment to reduce TPH & BTEX in soil stockpiles. Groundwater treatment by air stripping.

Former Staff

9/18/1990

Update or Other Action

RAPR; RZA plan for short term vapor extraction at former Mapco Express #5002.

Former Staff

10/2/1990

Update or Other Action

REM; Disposal of stockpile SP-2 and SP-7 at Anchorage Regional Landfill.

Former Staff

10/10/1990

Update or Other Action

RAPR; RZA plan for soil remediation; focus on Stockpile 14-7 with bio-feasibility study. Three stockpiles had previously been equipped with PVC vents and seeded with fertilizer to promote volatilization and bio-remediation.

Former Staff

10/12/1990

Update or Other Action

F; Short term vapor extraction test performed by RZA.

Former Staff

11/26/1990

Update or Other Action

RAPR; Preliminary vapor extraction as-built plan for ADEC review; VE system in place and continuously operating since 11/15/90. Included plan to determine vapor extraction zone of influence.

Former Staff

12/17/1990

Update or Other Action

F; RZA Inc. sends vapor extraction operation report to DEC for 1st week of operation. Free product layer of approximately .44' was confirmed at soil vapor extraction well SVX-1 11/29/90 & .01' at well HC-2.

Former Staff

4/12/1991

Institutional Control Record Established

Date of Compliance order by Consent.

Keather McLoone

5/1/1992

Update or Other Action

LCAR; Soil vapor extraction system is operating. Groundwater treatment system is being revamped due to failure to meet waste discharge permit standards for lead and benzene. Current water recovery plans call for pumping 2 gallons per minute from one recovery well. Letter responding to Mapco requested an updated corrective action plan by not later than June 15, 1992. Additional site assessment work has been conducted at Alaska Pollution Control, located to the west of the site. Results are pending. three water wells at Alaska Pollution Control are in the process of being abandoned. Requested additional ground water investigation to define full extent and location of ground water contaminant plume to the north-northwest of the site.

Former Staff

6/1/1992

Update or Other Action

CAPR; Letter sent to Shannon and Wilson regarding relocating soils from MAPCO #1 to MAPCO #2 for VES treatment. DEC requested some soil cell design criteria which were subsequently met by MAPCO. Soils were successfully treated and taken off site later in the summer to be used as upland fill for a new MAPCO.

Former Staff

6/29/1992

Update or Other Action

CAPR; Workplan received 19 May 1992 for a new Class C well on Alaska Pollution Control Property (previous well was affected by pollution from MAPCO 2). Sent letter back to RZA-RCRA requesting more information and a meeting.

Former Staff

7/7/1992

Update or Other Action

Proposal of 6/22/92 for Groundwater Remediation System reviewed. Approval was given to start remediation. MAPCO must publish public notice of local contamination. Text of public notice approved 7/8/92.

Former Staff

7/25/1994

Update or Other Action

LCAR; Groundwater monitoring and VES

Former Staff

10/1/1994

Update or Other Action

COMR; Complaint received.

Former Staff

10/15/1994

Site Visit

COMI; Complaint investigated.

Former Staff

10/20/1994

Update or Other Action

LCAR; Performed a Corrective Action Report review.

Former Staff

11/21/1994

Update or Other Action

LCAR; Review monitoring well reports.

Former Staff

3/18/1995

Update or Other Action

LCAR; Reviewed quarterly reports.

Former Staff

7/15/1995

Update or Other Action

LCAR; Reviewed quarterly monitor well report required by COBC.

Former Staff

7/25/1995

Update or Other Action

MEET; Met with RP to discuss status of site. (action code was CAPR)

Former Staff

8/15/1995

Update or Other Action

LCAR; Reviewed a report on impacted area wells.

Former Staff

9/15/1995

Update or Other Action

CAPR; Reviewed files.

Former Staff

11/20/1997

Update or Other Action

ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: MAPCO EXPRESS

Former Staff

11/11/2000

Update or Other Action

Received Historical Site Summary

Lynne Bush

2/5/2001

Underground Storage Tank Site Characterization or Assessment

Approved MW decommissioning plan

Lynne Bush

3/14/2001

Update or Other Action

Put copy of potential off-site impact study from Parker Drilling (L55.25) in this file.

Lynne Bush

9/17/2001

Update or Other Action

Changed ADEC Project Manager from Bush to Wiegers

Cynthia Pring-Ham

6/17/2002

Update or Other Action

Corrected address to 10630 Old Seward Highway (was 10800)

Janice Wiegers

11/21/2002

Update or Other Action

Fall monitoring report submitted. Product observed in MW-22 (property north of Williams site). 1 gallon of product removed with slow recharge. Apparent increase in benzene observed downgradient of MW-22. Highest benzene concentration detected on Williams property in MW-28 (12,000 ppb).

Janice Wiegers

3/11/2003

Update or Other Action

Per J. Wiegers, changed file number from L30.02 to 2100.26.018

Wendy Uzzell

5/1/2003

Update or Other Action

Monitoring well installation and drinking water decommissioning report submitted. Drinking water well decommissioned on property to north. Monitoring wells MW-29 through MW-31B installed and sampled. MW-31A installed in deeper water bearing unit (35-45 ft bgs). Maximum benzene (24,000 ppb) and GRO (120 ppm) detected in MW-31A. Soil sample results indicated soil contamination present in smear zone: highest historical concentrations still detected at MW-22 (location of free product).

Janice Wiegers

6/19/2003

Document, Report, or Work plan Review - other

Spring remediation and monitoring report submitted. Hydrocarbon recovery rates have remained low since 2002. Benzene has not been detected in the exhaust since 2000. The highest groundwater concentrations were found in the deep well MW-31A (benzene at 21,000 ppb) approximately 20 feet below the shallow wells. Benzene was not detected in the associated shallow groundwater well (MW-31B). This well is located near and downgradient of former UST arrays on the adjacent property. Product was present in MW-22.

Janice Wiegers

11/14/2003

Document, Report, or Work plan Review - other

Remediation and groundwater monitoring report submitted. Product present in off-site wells. The highest dissolved concentrations found on-site were in MW-28 (16,000 ppb benzene). The deep well (MW-31A) contained the highest off-site dissolved concentrations, but contaminants were not detected in shallow wells around the deep well. Vertical migration or migration at depth in the aquifer needs further investigation.

Janice Wiegers

3/19/2004

Document, Report, or Work plan Review - other

Workplan for lead scavenger sampling approved. EDB will be analyzed with EPA method 8260. Further evaluation with a method with a lower detection limit may be conducted in future sampling events.

Janice Wiegers

6/17/2004

Update or Other Action

File review to approve cost recovery invoice.

Lynne Bush

7/7/2004

Update or Other Action

On 07 July 2004, Bush met with Holiday representative Bruce Anthony; Williams Express representative Terrie Blackburn; and Shannon & Wilson representatives Matt Hemry, Ben Heaver, and Tim Terry. The topic of discussions was plans for future activities at all former Williams Express Stations.

Lynne Bush

9/8/2004

Update or Other Action

Holiday will be assuming responsibility for investigative and remediation activities at all former Williams Express Stores, but legal responsibility is divided by store. Holiday has renumbered their stores as: 5001=601; 5002=602; 5005=605; 5005=605; 5006=606; 5007=607; 5008=608; 5010=610; 5014=614; 5016=616; 5018=618; 5024=624; 5025=625; 5030=630; 5031=631; 5050=650. While Holiday will oversee the work at the former Williams’ stations, these sites remain the responsibility of Williams. The numbers of these sites remain the same: 5003; 5004; 5009; 5012; 5015; 5017; 5021; and 5034.

Lynne Bush

9/27/2004

Update or Other Action

Approved delay for bi-annual reporting to include more recent remediation monitoring data. The new target date is early December.

Lynne Bush

10/1/2004

Update or Other Action

A decision was made in 2004 by Williams and Holiday to sample selected sites for lead scavengers. The purpose of this investigation is to determine whether or not lead scavenger compounds such as ethylene dibromide and ethylene dichloride are viable constituents of concern. This site was included for lead scavenging investigation based on risk ranking. Risk rank was determined by the presence of wells and potential receptors, known period of leaded gasoline sales at this site, the known presence/absence of Pb scavengers, and the general level of hydrocarbon concentrations. The first event for chosen high risk sites occurred in Spring 2004. Station 2 is the only site where lead scavenger analysis exceeded ADEC target cleanup levels. Monitoring Well 27 had an ethylene dichloride level of 0.202ppm.

Lynne Bush

10/1/2004

Update or Other Action

Future plans for this site include continued monitoring, continued operation of the remediaiton system, evaluation of the costs for site remediation operation, evaluation of off-site migration, evaluation of the three aquifers indentified at this site for migration and contaminant conscentration parameters, establishment of an off-site point of compliance, possible assessment of gradient and plume extent in each aquifer, and installation of additional monitoring wells. A work plan should be submitted prior to the end of 2004.

Lynne Bush

10/20/2004

Update or Other Action

The Soil Vapor Extraction system operation schedule for this site is continuous and the sampling frequency is quarterly. The Air Injection System operation schedule for this site is continuous and the sampling frequency is quarterly. The groundwater sampling frequency remains bi-annually in March and September. Free product is present and being monitored at this site on a monthly basis. Groundwater flow is to the west as of April 2004.

Lynne Bush

1/11/2005

Update or Other Action

Work plan to install two new monitoring wells received.

Lynne Bush

1/12/2005

Update or Other Action

Received work plan for installation of two new monitoring wells in the vicinity of MW-16.

Lynne Bush

1/18/2005

Document, Report, or Work plan Review - other

Reviewed semi-annual report. General groundwater flow direction is to the west, but on-site, the direction is west-northwest. The vapor extraction system recovers 4.9 pounds per day.

Lynne Bush

1/18/2005

Document, Report, or Work plan Review - other

The vapor extraction blower should be upgraded, the system should be operated continuously, product thickness in wells with product should be measured monthly, monitoring well MW-19 should be decommissioned, and characterization of the intermediate and deep aquifers should be planned.

Lynne Bush

1/18/2005

Update or Other Action

E-mail request for work plan to accomplish goals determined recently.

Lynne Bush

1/18/2005

Update or Other Action

Work plan approval to install two new wells in the vicinity of monitoring well MW-16 approved via e-mail and fax. These wells will assess the intermediate and deep aquifers.

Lynne Bush

3/15/2006

Update or Other Action

Approval of July 5, 2005 work plan. 1. Suspend monthly product monitoring, dependent upon observations in future groundwater monitoring events; 2. Conduct annual sampling collection for MW-18, MW-20, MW-26, MW-21 and MW-31-A; 3. Suspend sample collection for MW-11, MW-13, and MWP-3; 4. Conduct semi-annual sample collection for the remaining viable wells; 5. Decommission MW-19; 6. Provide a summary report of activities with the annual report.

Lynne Bush

5/9/2006

Update or Other Action

Project management transferred from Bush to O'Connell.

Aggie Blandford

5/11/2006

Document, Report, or Work plan Review - other

Rec'd April to Dec. 2005 Monitoring Report. VES Blower replaced, April 2005. Free product measured in MW22, 10/12 months in 2005. Benzene exceeded Table C in MW-15, MW-17, MW-21, MW-22, MW-23, MW-26, MW-27, MW-28, MW-29, MW-30, MW-31a, and MW-32 during one or more 2005 sampling events. Next monitoring event in spring 2006.

Bill O'Connell

3/16/2007

Exposure Tracking Model Ranking

Former Staff

6/12/2007

Document, Report, or Work plan Review - other

Received 2006 Monitoring report. QA/QC conducted. 18 wells were sampled in spring 2006 and 13 in the fall. 0.15 feet of product was encountered in MW-22 during the spring event. Groundwater contamination above Table C cleanup levels is present in the upper two of three water bearing zones at the site and off site to the northwest. 2006 sampling results are generally consistent with historic trends.

Bill O'Connell

7/17/2008

Document, Report, or Work plan Review - other

Receipt of 2007 report electronically. Review included laboratory review checklist. S&W reports that Holiday may use ISOC and may shutoff and remove VEW-2 and VEW-3. The VES will continue to operate.

Keather McLoone

9/5/2008

Update or Other Action

ADEC approved dropping MW-12 from the program because it has not been found during the two 2007 events and was ND for 3 events in a row. During 9/24/08 meeting there was some discussion about whether the well was missing or not. Site visit to be conducted later in September will include an attempt to clarify the status of this well.

Keather McLoone

6/5/2009

Document, Report, or Work plan Review - other

Review of Oxygen Releasing Compound Pilot Study Work Plan. Focused study to include MW-28, in which a series of ORC socks will be installed. Upgradient well MW-13 and downgradient well MW-30 will also be included in the study. Pre-ORC installation, July, and September parameters will include GRO/BTEX, DO, pH, temperature, redox potential to evaluate the effectiveness. Heterotrophic plate count and ferric/ferrous iron will also be measured pre-ORC installation and in September. DEC has requested to be notified when pre-installation measurements and soc installation take place.

Keather McLoone

7/23/2009

Document, Report, or Work plan Review - other

Review of January to December 2008 Remediation System and Groundwater Monitoring report submitted 7/1/09. The VES was part of initial remedial efforts at this site (1990-1995) and along with a P&T. In 1995 the VES was modified. During 2008, the VES generally operated on a continuous basis with the dilution valve and the seven VES lines for an estimated 344 days. System monitoring was conducted on a monthly basis and analytical samples were to be collected quarterly. Individual lines typically have higher concentrations than the combined exhaust, likely due to the dilution valve. The AIS operated on a continuous basis with the bleed valve closed and cycles between the left and right banks with each bank operating for a 12-hour time period. Monitoring of this system consisted of recording blower pressure and measuring flow in the individual lines. The average flow rates of the lines were generally less than the target range and exhibited variability thru the monitoring period. Previous efforts to increase pressure have been generally unsuccessful. Groundwater samples were collected from seven wells in April 2008 and from 20 wells in September 2008. Samples for natural attenuation parameters were collected from MW-27, MW-28, and MW-30 during September's event. These analyses were also performed on water collected from MWP-3 and MW-13. Review included laboratory review checklists.

Keather McLoone

3/18/2010

Document, Report, or Work plan Review - other

Receipt and initial review of Oxygen Release Compound Pilot Study report. Results of study are inconclusive and other options will be discussed. The effect of the ORC soc was deemed to be localized to the application well and not produce a "rapid decrease in hydrocarbon concentrations at the site".

Keather McLoone

3/24/2010

Update or Other Action

Phone conversation with S&W to discuss the possibility of attempting an "enhanced fluid extraction" technique at MW-28 this upcoming season as a followup to the Pilot Study done on the ORC socs.

Keather McLoone

4/23/2010

Update or Other Action

confirmed with AWWU that this location is on city water - unclear if the private well that is listed on the Anchorage Live website is one that has been decommissioned.

Keather McLoone

4/29/2010

Document, Report, or Work plan Review - other

Review of Source Area Soil-Gas and Groundwater Evaculation Work Plan received via email on 4/20/10. Signed acceptance page was returned via email on today's date with a request that DEC be notified for the first treatment event so that a site visit can be conducted.

Keather McLoone

5/5/2010

Site Visit

Site visits to observe groundwater sampling and vacuum truck extraction. Shannon & Wilson communicated via email that approximately 200 gallons of groundwater were removed during the several hours that the vac truck was hooked up to the top of the well casing.

Keather McLoone

2/24/2011

Document, Report, or Work plan Review - other

Reviewed Source Area Soil Gas and Groundwater Evacuation Report, received February 15, 2011. A vacuum truck was used on May 5, June 8, and July 7 to remove soil gas and groundwater from MW-28. Groundwater samples were collected before and after the first and last of these purge events. This well was also sampled in September as part of the annual sampling effort. On May 5, the ORC socks were removed. A vacuum of about 12 psi was applied on May 5 for 5 1/2 hours removing about 283 gallons of liquid. For this and each of the other two events, groundwater was below the top of the well screen, so it is likely that any soil gas or groundwater was purged. The other two events involved 8 hours of applied vacuum. About 270 gallons were removed in June and about 310 gallons in July. The report concludes that the effectiveness of this approach could not be measured. Review included laboratory data review checklists.

Keather McLoone

6/6/2011

Document, Report, or Work plan Review - other

Received January-December 2010 Remediation System and Groundwater Monitoring report. AIS was not operating between May 2009 and March 2010, then operated for 5 months before being turned off and found to be inoperational.

Keather McLoone

4/30/2012

Document, Report, or Work plan Review - other

Received January-December 2011 Remediation System and Groundwater Monitoring Report. Review included laboratory data checklist. Seventeen wells were sampled in September. The VES operated 358 days last year. The AIS has not operated since September 2010, despite last year's comment letter.

Keather McLoone

9/27/2012

Meeting or Teleconference Held

Conducted annual fall meeting with Holiday & their consultant (S&W). Discussed potential contaminant spread from HSS 602 onto First Student property (Operated by Parker Drilling) and the need for remediation. Holiday contends that contamination on First Student property is not the result of their historic releases (or is largely the result of a co-mingled plume). Data analysis will be conducted, and another meeting will occur in November to address this claim and decide upon a future course of action. ADEC also requested 1) a spring sampling event to be conducted in Spring 2013, if possible, 2) Documentation of any agreed modifications to the COBC agreements/requirements, 3) response on feasibility of adding nodes to VEAIS system to address high contaminant levels on First Student property, 4) Alternative strategies for addressing high contaminant levels if adding nodes isn't feasible, 5) Routine measurement of product thickness in wells. Item #s 3 & 4 will be put on hold until after the follow-up meeting in November. Also discussed HSS #606 and 630.

Richard Bernhardt

12/7/2012

Meeting or Teleconference Held

Project manager participated in a follow-up RP meeting with Holiday and their consultants from S&W where I summarized the 25 year case history for this site, focusing on evidence of source areas (or lack thereof) on both Holiday’s property and their neighbor to the north (Parker Drilling… now First Student). I outlined a path forward that involves active remediation with generalized measures of success. The plume doesn’t appear to be migrating, but retains free product and significantly elevated hydrocarbon concentrations that are beyond the radius of influence of the existing remediation system, which now only serves as a vapor extraction system. Holiday is interested in progressing toward site closure and proposed transitioning into Monitored Natural Attenuation (MNA) as a remediation strategy. However, this is not currently a viable option based on an inconclusive/ineffective ORC pilot study and contaminant concentration trends over the site’s extended history. Optimizing the methods from S&W’s Soil Gas and Groundwater Evacuation Pilot Study and treating the plume in its central hotspot (area of highest concentration) appears to be the most promising means of reducing the plume and progressing to a state where Enhanced Natural Attenuation (ENA) or MNA may become viable options. ADEC also proposed that the current remediation system be turned off in exchange for optimizing and implementing the SG&GWE study in the heart of the plume on Holiday’s and Parker’s property. ADEC will proceed by developing achievable performance metrics, endpoints for the SG&GWE approach, and strategies to allow for a transition to ENA and/or MNA with long-term monitoring. Meanwhile, Holiday will consider whether they would like to explore the SG&GWE approach with the understanding that a remediation system must remain in place, alternative remediation options are becoming limited, and the current vapor extraction system has outlived its usefulness without having significant upgrades.

Richard Bernhardt

4/29/2013

Document, Report, or Work plan Review - other

Reviewed Annual Report for Holiday 602. The VES portion of the remediation system operated normally in 2012, the AIS has not operated since September 2012. Four vapor samples were collected from the VES in 2012 and did not contain detectable concentrations of contaminants. Groundwater samples were collected from 17 wells during the annual monitoring event in September 2012. The groundwater elevation was approximately 3 feet higher than in September 2011, likely due to above average precipitation in the Anchorage area during this month. This resulted in generally lower concentrations of hydrocarbons detected in wells on site, and generally higher concentrations in downgradient wells. The highest concentration of benzene was detected in well MW-23 at 0.285 mg/l. MW-28, which typically contains the highest concentrations of benzene, had benzene at 0.00348 mg/l. The report indicates that the screened interval at monitoring wells MW-14, -16, -17, -18, -22, -23, -28, -29, -32, and -33 was below the static water level in these wells indicating the data should be considered as screening level data and not representative of aquifer conditions. Generally monitoring data indicate the plume is stable.

Bill O'Connell

7/8/2013

Document, Report, or Work plan Review - other

Reviewed work plan for the decommissioning of MW-31A and the installation of a replacement well named MW-34, which will be installed approximately 5 feet to the east of the former MW-31A. Soil samples will be collected and the well will be screened below the water table at 35-45 feet bgs. The well will then be purged and sampled.

Bill O'Connell

12/2/2013

Document, Report, or Work plan Review - other

Reviewed Monitoring Well Replacement Report for Holiday 602. Monitoring well MW-31A was decommissioned in accordance with ADEC guidance and monitoring well MW-34 was installed approximately 5 feet to the east. One soil sample was collected where groundwater was initially encountered at 21.5 to 22 feet bgs and did not contain detectable concentrations of contaminants. The well was completed to 45 feet bgs to match the former depth of MW-31A. Drill cutting from below the water table exhibited sheen and hydrocarbon odor. The well was sampled during the annual monitoring event and the groundwater data will be reported at a later date.

Bill O'Connell

12/2/2013

Document, Report, or Work plan Review - other

Reviewed Monitoring Well Replacement Report for Holiday 602. Monitoring well MW-31A was decommissioned in accordance with ADEC guidance and monitoring well MW-34 was installed approximately 5 feet to the east. One soil sample was collected where groundwater was initially encountered at 21.5 to 22 feet bgs and did not contain detectable concentrations of contaminants. The well was completed to 45 feet bgs to match the former depth of MW-31A. Drill cuttings from below the water table exhibited sheen and hydrocarbon odor. The well was sampled during the annual monitoring event and the groundwater data will be reported at a later date.

Bill O'Connell

4/11/2014

Document, Report, or Work plan Review - other

Reviewed 2013 Remediation System and Monitoring Report for HSS 602. The remediation system consisted of an air injection system (AIS) and a vapor extraction system (VES). The AIS has not operated since 2010. The VES has experienced diminishing returns and vapor samples collected in July and October 2013 did not contain detectable concentrations of contaminants. The report recommends switching to pulse operation rather than continuous operation. Groundwater samples were collected from 18 monitoring wells in October 2013. Samples collected during this monitoring event were collected following purging of the monitoring wells as opposed to samples that were collected in previous years using the no-purge method. Free product was not observed in any of the monitoring wells sampled in 2013. Groundwater at the site appears to be present at three intervals, shallow, intermediate and deep and groundwater elevations have been increasing over recent years. Contaminant concentrations in the shallow plume are somewhat variable however the plume appears stable overall. Benzene was detected up to 3.38 mg/l in MW-23 in the shallow plume. Monitoring well MW-31A in the intermediate plume has shown the highest levels of contamination at the site, with benzene detected at 16.1 mg/l. The leading edge of this plume is monitored in MW-32 which has shown increasing concentrations in recent sampling events, though lower than historical concentrations detected in 2005. The deep plume is delineated by sentry well MW-33 which did not contain contaminants above cleanup levels in 2013. Contaminant concentrations are elevated above cleanup levels both on and off site but exhibit long term decreasing trends.

Bill O'Connell

5/22/2014

Document, Report, or Work plan Review - other

Reviewed Groundwater Sampling Program Modification for HSS 602. The objective of the modified plan is to focus on plume boundary/sentinel wells and only sample source area wells every other year. Groundwater was sampled quarterly from 1993 to 2008, then annually from 2008 until 2014. In 2013, groundwater samples were collected from 18 wells. Because contaminant trends in groundwater are well established, the modified plan proposes sampling 9 wells on an annual basis and nine wells on a biennial basis. Four wells that are not part of the current sampling program, MWP-3, MW-11, MW-12, and MW-13 will be decommissioned. Monitoring wells that will be sampled on an annual basis include MW-21, MW-27, MW-30, MW-32, MW-33, MW-17, MW-18, MW-20 and MW-14. Wells moved to biennial sampling include MW-15, MW-16, MW-26, MW-31B, MW-22, MW-23, MW-28, MW-29 and MW-34.

Bill O'Connell

6/27/2014

Document, Report, or Work plan Review - other

Monitoring wells MWP-3, MW-11, MW-1, and MW-13 were decommissioned in accordance with ADEC guidance. These wells were removed from the monitoring program between 2005 and 2008.

Bill O'Connell

5/8/2015

Update or Other Action

VES system turned off for rebound test.

Bill O'Connell

5/18/2015

Document, Report, or Work plan Review - other

Reviewed 2014 Remediation System and Groundwater Monitoring Report for HSS #602. The vapor extraction system worked on a pulse schedule in 2014 consisting of two, 12-hour operating periods per week. A sample of the system exhaust did not contain detectable concentrations of contaminants and the system was shut off in May 2015 for a rebound test. Groundwater samples were collected from 16 monitoring wells, which are completed in the three different water bearing zones present at the site. Results from the shallow zone indicate long term decreasing contaminant trends and a delineated plume. Results from the intermediate zone indicate the highest contaminant levels at the site in well MW-34, with benzene detected at 18.4 mg/l. The leading edge of the plume in the intermediate zone is in the vicinity of MW-32, which has contained increasing concentrations of benzene since 2010. The deep plume appears stable and delineated.

Bill O'Connell

3/8/2016

Document, Report, or Work plan Review - other

Reviewed 2015 Remediation System and Groundwater Monitoring Report for Holiday 602. The vapor extraction system operated for 420 hours in 2015, 12 hours per day on Mondays and Fridays only. Vapor samples collected from the VES system did not contain detectable concentrations of contaminants. The air injection system has not operated since 2010. Groundwater samples were collected from 16 monitoring wells in September 2015. MW-16 was damaged and could not be sampled. Groundwater samples continue to show elevated levels of benzene both on and off the source property with detections up to 19.1 mg/l in MW-34 north of the source property.

Bill O'Connell

4/20/2016

Document, Report, or Work plan Review - other

Reviewed Work Plan for Remediation System Decommissioning at Holiday 602. The vapor extraction/air injection (VEAIS) was installed in 1997. The AIS was shut down in 2010 and was not restarted. The VES was shut down in May 2015 after vapor sampling indicated limited effectiveness of the system. The work plan indicates the above ground components of the system will be removed from the site. Below grade components of the system will be filled with concrete or bentonite then patched to match the surrounding surface.

Bill O'Connell

1/10/2017

Document, Report, or Work plan Review - other

Reviewed remediation system decommissioning report for HSS 602. The combination vapor extraction/air injection system was installed in 1997. The AIS was shut down in 2010 and the VES was shut down in 2015. The remaining VES wells were cut off and filled with bentonite. Below grade lines were filled with bentonite, cut off and capped below ground surface and left in place. Above grade equipment was removed from the property.

Bill O'Connell

4/12/2017

Document, Report, or Work plan Review - other

Reviewed 2016 Annual Groundwater Monitoring Report for HSS 602. Samples were collected from 15 monitoring wells in September 2016. MW-16 and MW-22 had damaged well casings and could not be sampled, MW-26 is presumed destroyed. Petroleum contamination remains in groundwater above DEC cleanup levels both onsite and offsite at the two properties to the north and is present in the shallow, intermediate, and deep water bearing zones. Contaminant concentrations have varied overt time and well MW-28 has had increasing benzene concentrations over the last 4 years, however this appears somewhat related to groundwater elevations, which have also varied by as much as 5 feet or more in some wells over the same time period. Report recommendations include decommissioning of MW-16 and repairing MW-22.

Bill O'Connell

9/22/2017

Update or Other Action

Damaged monitoring well MW-16 approved for decommissioning

Bill O'Connell

12/26/2017

Document, Report, or Work plan Review - other

Reviewed 2017 groundwater monitoring report for Holiday Station Store 602. Groundwater samples were collected from 15 monitoring wells in October 2017. Three wells could not be sampled: MW-22 is damaged, MW-26 could not be located and MW-34 contained 0.2 feet of free product. Groundwater is present in three distinct water bearing zones and remains contaminated above cleanup levels at the source property and on the two adjacent properties to the north.

Bill O'Connell

6/10/2019

Document, Report, or Work plan Review - other

October 12-13, 2017 groundwater monitoring event. Up to 4,090 ug/l benzene in the monitoring wells sampled this monitoring event. Concentrations increased in 6 of the 15 monitoring wells sampled. Free product of 0.2 feet was measured in monitoring well MW-34 this monitoring event. Depth to groundwater was 15.08 to 26.15 feet below ground surface. Groundwater historically flows to the northwest. During this monitoring event the monitoring wells were purged prior to sampling. The groundwater samples were collected using a bailer except for monitoring wells MW-32, MW-33, MW-34, and MW-35 that were collected using a submersible pump with the pump intake in the middle of the 10 foot well screen with a top of well screen that is submerged under the groundwater surface to assess contamination in the deeper aquifer at the site. Because the volatile samples were collected using a bailer they are considered biased low due to loss of volatiles using that method. MW-22 was not sampled due to bentonite in the monitoring well. Monitoring well MW-26 could not be located. Monitoring well MW-17, MW-18, MW-23, and MW-29 had a submerged well screens (groundwater 6.37', 9.62', 0.08', and 1.4' above screened interval respectively) the results in these monitoring wells may be biased low.

Robert Weimer

6/11/2019

Document, Report, or Work plan Review - other

September 17-19, 2018 groundwater monitoring event. Up to 16,300 ug/l benzene, 19,100 ug/l toluene, 1,960 ug/l ethylbenzne, and 3,900 ug/l xylenes in the monitoring wells sampled this monitoring event (the highest concentration was in monitoring well MW-34 which is in the deeper aquifer). Concentrations increased in 5 of the 13 monitoring wells sampled. No measurable free product this monitoring event. Depth to groundwater was 17.14 to 26.97 feet below ground surface. Groundwater historically flows to the northwest. During this monitoring event the monitoring wells were purged prior to sampling. The groundwater samples were collected using a bailer except for monitoring wells MW-32, MW-33, MW-34, and MW-35 that were collected using a submersible pump with the pump intake in the middle of the 10 foot well screen with a top of well screen that is submerged under the groundwater surface to assess contamination in the deeper aquifer at the site. Because the volatile samples were collected using a bailer they are considered biased low due to loss of volatiles using that method. MW-22 was not sampled due to bentonite in the monitoring well. Monitoring wells MW-20 and MW-26 could not be located. MW-18 was not sampled because it was damaged (it also had a submerged well screen, 7.56' above). Monitoring well MW-17 had a submerged well screen (water 4.7' above) the results in this monitoring well may be biased low.

Robert Weimer

6/17/2019

Meeting or Teleconference Held

Meeting with Holiday and their consultant (Shannon & Wilson). In 2019 they are to conduct further release investigation including soil sampling from borings, continue ground water monitoring, switch to using an in-well positive displacement pump (instead of bailers due to the loss of volatiles) with the intake in the top foot of the water column/screened interval. They proposed to decommission MW-22, suspend sampling of MW-26, repair/replace MW-30, install a monitoring well in the "intermediate zone" north of MW-32 and another east of MW-18, and install a monitoring well in the "shallow zone" north of MW-14.

Robert Weimer

12/28/2020

Site Characterization Workplan Approved

The CSP approves the Work Plan for Additional Site Characterization Activities and Annual Groundwater Sampling prepared by Shannon & Wilson, Inc. on December 28, 2020.

Randy Guintu

12/28/2020

Site Characterization Workplan Approved

The CSP approves the Work Plan for Additional Site Characterization Activities and Annual Groundwater Sampling prepared by Shannon & Wilson, Inc. on December 28, 2020.

Randy Guintu

11/12/2021

Offsite Soil or Groundwater Disposal Approved

The ADEC approved for one 55-gallon drum of monitoring well purge water, contaminated with GRO, VOCs, and PAHs, to be shipped and disposed of at the US Ecology facility in Anchorage. The ADEC also approved for one 55-gallon drum of development waster with all contaminants below ADEC cleanup levels (CULs) to be discharged to the property, and one 55-gallon drum of excavation soil, with contaminants below ADEC CULs, to be landspread on the property.

Flannery Ballard

2/21/2023

Site Characterization Report Approved

ADEC issued approval letter for "Release Investigation and Groundwater Sampling Activities, Holiday Station Store No. 602”, dated May 2022. The 2021 groundwater sample data continue to indicate elevated dissolved-phase hydrocarbon concentrations in both on-Property and off-Property monitoring wells. Concentration gradients and distribution patterns remain consistent with the presence of discrete on-Property and off-Property source areas. The data also indicate different plume characteristics at discrete depth intervals. The plume in the “shallow” zone has historically been defined, with the leading edge in the approximate vicinity of Well MW-15 and former Well MW-16. The leading edge of the plume of the ‘intermediate’ zone located in the vicinity of Well MW-32. With the exception of the October 2007 sample, benzene, toluene, ethylbenzene, and xylenes (BTEX) concentrations in samples from Well MW-33, which is screened in the “deep” zone, have either been non-detect or less than ADEC Table C cleanup levels. Groundwater flow direction is to the west/northwest.

Alena Voigt

4/17/2023

Meeting or Teleconference Held

Teleconference with RP representative Hal Hatfield, S&W Environmental consultant Dan McMahon, EPM1 LKB, and PM AV regarding a path towards site closure.

Alena Voigt

5/31/2023

Site Characterization Workplan Approved

The ADEC CSP reviewed the “Work Plan for Additional Site Characterization and Groundwater Monitoring Activities, Holiday Station Store No. 602” dated May 17, 2023, from Shannon & Wilson, Inc. The project activities will consist of advancing three soil borings, installing three groundwater monitoring wells, collecting soil and groundwater samples, managing investigation-derived waste (IDW), and preparing a summary report.

Alena Voigt

9/1/2023

Site Characterization Workplan Approved

The ADEC CSP reviewed the “Work Plan for Decommissioning One Monitoring Well; 10560 Old Seward Highway, Anchorage, Alaska” dated September 1, 2023, from BGES, INC. The scope of work includes decommissioning one monitoring well (MW-23), stockpile soil sampling, and preparation of a summary report.

Alena Voigt

11/8/2023

Site Characterization Report Approved

The CSP reviewed the “Monitoring Well Decommissioning & Stockpile Sampling; 10560 Old Seward Highway Letter Report,” dated October 30, 2023, from BGES, INC. (BGES). The report documents decommissioning one monitoring well, identified as MW-23, and stockpile soil sampling. Stockpile soil approved to be spread on-site.

Alena Voigt

Contaminant Information

Name

Level Description

Media

Comments

Control Type

Type	Details
COBC	1991 includes 14 Mapco stations

Requirements

Description

Details

2018 Annual Groundwater Monitoring Report

2017 Annual Groundwater Monitoring Report

No associated sites were found.

Missing Location Data

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Alaska Department of Environmental Conservation

Site Report: Holiday Station Store #602, formerly Williams Express Store #5002

Site Chronology

IC / Closure Details

Documents

Associated Sites

Problems/Comments

Action Information

Contaminant Information

Control Type

Requirements

2018 Annual Groundwater Monitoring Report

2017 Annual Groundwater Monitoring Report

Missing Location Data

State of Alaska Department of Environmental Conservation