| Action Date |
Action |
Description |
DEC Staff |
| 7/29/1976 |
Update or Other Action |
In June 1976, diesel contaminated water discharged into the Cook Inlet from a storm drain. Reportedly, the coupling between two fuel tanks located off the southeast corner of the maintenance building was leaky. 23,000 gallons of diesel oil spilled into the fill materials surrounding the USTs. 19,000 gallons of diesel fuel was recovered from recovery wells and from utility hole #8 in the storm drain system adjacent to the UST area. Approximately 4,000 gallons of diesel fuel was unaccounted for. |
Grant Lidren |
| 5/17/1993 |
Site Added to Database |
|
Former Staff |
| 5/17/1993 |
Leaking Underground Storage Tank Release Confirmed - Petroleum |
LUST Site created in CSP for source area ID 77835 ADD; Waste oil contamination. |
Former Staff |
| 6/21/1993 |
Document, Report, or Work plan Review - other |
On this date, ADEC received the UST Removal Site Assessment Report for Sea-Land Freight service submitted by Gilfilian Engineering dated June 15, 1993. Contamination was encountered during removal of a 1,500 gallon waste oil tank in 1993. The tank was located at the warehouse building on the southwest corner of the property. The top of the tank was 15 inches bgs. Petroleum contamination was noted at the fill pipe. When the tank was excavated, groundwater was encountered at 5 feet bgs. Twenty-five cubic yards of visually contaminated soil were stockpiled on site. The excavation was 10 by 12 feet and 7 feet deep. Four soil samples collected from the sidewalls just above the excavation groundwater depth contained EPH up to 7,980 mg/kg, VPH up to 2,030 mg/kg, and total BTEX up to 838.1 mg/kg. On July 28, 1993, additional contaminated soil was excavated to the north and east of the UST area. Excavation to the south and east was limited by the property line and the shop building respectively. Soil samples collected contained petroleum constituents; the extent of contamination was not defined. The contaminated soil was transported to ASR. |
Grant Lidren |
| 7/9/1993 |
Underground Storage Tank Site Characterization or Assessment |
SA1R; Removal of 1500 gallon waste oil tank. Groundwater encountered at 5 feet. Contaminated soil (25 yards) excavated, stockpiled on site, and returned to the excavation. Department requested release investigation. |
Former Staff |
| 7/28/1993 |
Leaking Underground Storage Tank Cleanup Initiated - Petroleum |
LCAU; Excavating and stockpiling contaminated soil, attempting to determine limits of contamination. |
Former Staff |
| 12/14/1993 |
Update or Other Action |
On this date ASR received 93.07 tons of petroleum impacted soil |
Grant Lidren |
| 2/14/1994 |
Update or Other Action |
On this date, ADEC received the Site Assessment Report for Sea-Land Freight service submitted by Gilfilian Engineering dated February 14, 1994. Four soil borings were advanced adjacent to the USTs 1, 2, 4, 5, 6, and 7 at the maintenance building. During the investigation, a boring was advanced off the SE corner of the maintenance building adjacent to USTs 4, 5, 6, and 7. A soil sample collected 5 to 7 feet bgs contained VPH at 1,090 mg/kg, EPH at 1,450 mg/kg, and benzene at 2.15 mg/kg. Groundwater samples contained EPH at 787 mg/L and benzene at 9.23 mg/L. Inside the maintenance shop at the north end of the building a soil sample collected 2 feet bgs contained VPH up to 3,430 mg/kg, EPH up to 4,560 mg/kg, and TPH up to 6080 mg/kg. soil samples collected 8 to 10 feet bgs did not contain Contamination above cleanup levels |
Grant Lidren |
| 9/15/1997 |
Update or Other Action |
In 1997, three underground storage tanks (USTs) located on the south side of the
Maintenance Shop were upgraded to meet current regulatory standards. During
the upgrades, a 10,000-gallon UST was damaged, and an estimated 5,600 gallons of fuel
were released. Response activities reportedly recovered all of the the fuel and removed
50 cubic yards of impacted soil. Some impacted soil may remain in conjunction with
two of the three tanks that were left in place. As part of the remedial solution, a passive
bioventing system consisting of six underground, horizontal, slotted PVC lines were
installed. The objective of the bioventing system is to promote in situ remediation
through the passive removal of volatile hydrocarbons and the addition of oxygen, which
supports aerobic degradation of hydrocarbons in the vadose (unsaturated) zone. |
Grant Lidren |
| 11/20/1997 |
Update or Other Action |
ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: SEALAND FREIGHT SERVICE, INC. |
Former Staff |
| 1/30/1998 |
Update or Other Action |
They upgraded more tanks - asked for a release investigation for the 2nd time. |
Former Staff |
| 10/2/1998 |
Site Visit |
Leaving a waste oil tank in place - ok'd by me |
Former Staff |
| 11/15/1998 |
Underground Storage Tank Site Characterization or Assessment |
ADEC received the UST Closure Assessment 1917 Tidewater Road dated November 1998 submitted by S&W. One 2,500 gallon motor oil UST was removed and one 2,500 gallon waste oil UST was filled with concrete and closed in place. A total of 85.23 tons of impacted soil was transported to ASR for thermal treatment. The excavations were backfilled with clean fill and clean overburden material. Confirmation soil samples collected from the motor oil UST tank excavation at the GW interface 8.5 to 9.5 feet bgs did not contain contaminant concentrations above ADEC cleanup levels. Four soil samples collected from the in place closed used oil UST 9.0 to 11.5 feet bgs at the groundwater interface contained TCE up to 0.0283 mg/kg. |
Grant Lidren |
| 9/2/1999 |
Release Investigation |
Rec'd draft wp fromHart-Crowser. Indicates a very large release in '76 that I was not aware of, as well as a couple of reports I have not seen. Needs revision, will so advise. Will also request missing data and reports. |
Former Staff |
| 6/30/2000 |
Release Investigation |
Approved work plan |
Former Staff |
| 7/17/2000 |
Update or Other Action |
Hart Crowser conducted a release investigation in 2000 to assess the impact of
documented releases from USTs located on the south side of the Maintenance Shop.
Four monitoring wells (HC-1, HC-2B, HC-3, and HC-4) were installed. Soil samples collected from the borings at 5 to 12 feet bgs contained benzene up to 1.87 mg/kg, ethylbenzene up to 1.60 mg/kg, xylenes up to 9.63 mg/kg, and DRO up to 345 mg/kg (HC-1 was the most contaminated boring at 5 to 7 feet bgs, soil samples collected 7.5 to 9.5 feet bgs were below CLs). Review of
analytical results from the monitoring wells indicated that groundwater concentrations
of benzene, gasoline-range organics (GRO), and diesel-range organics (DRO) exceeded
the ADEC groundwater cleanup levels (GCLs). All wells contained petroleum
hydrocarbon concentrations above GCLs with the exception of HC-4, located at the west
side of the former fuel canopy. |
Grant Lidren |
| 3/20/2001 |
Release Investigation |
Received report of recent work. CSX recommend application of the 10X Rule, setting commensurate ACLS for soil. They note that the VES is not working effectively, as I anticipated hearing. |
Lynne Bush |
| 5/2/2001 |
Update or Other Action |
Letter to Ray Koll |
Lynne Bush |
| 12/21/2001 |
Update or Other Action |
Bush -> Sundet |
Lynne Bush |
| 6/15/2002 |
Update or Other Action |
In 2002, Hart Crowser installed two new monitoring wells (HC-5 and HC-6) along the
Cherry Hill Storm Drain line to determine whether the storm sewer line was acting as a
preferential pathway for contaminant migration from the USTs. All existing wells were
sampled, with wells HC-1, HC-2B, HC-3, and HC-4 having similar results as in 2000. No
compounds were detected above GCLs in HC-5 and HC-6. Hart Crowser conducted two
more rounds of groundwater monitoring in November 2004 and March 2005. |
Grant Lidren |
| 10/8/2002 |
Update or Other Action |
On 10/8/02, CSP approved the plan Work Plan Well Installation CSX Lines LLC 1717 Tidewater Road Anchorage dated 10/1/02. The plan proposed 2 monitoring wells to be installed at the site and sampling of the 2 new and 5 existing monitoring wells. |
Rich Sundet |
| 8/12/2004 |
Update or Other Action |
File number reassigned from 2100.26.078 to 2100.26.238 due to duplication. |
Aggie Blandford |
| 9/23/2004 |
Update or Other Action |
On 9/23/04, CSP provided comments to HartCrowser's "Well Installation and Groundwater Monitoring Report, Horizon Termain Maintenance Facility" former Sealand and CSX facility. The report was dated 3/27/03 and received at DEC on 3/28/03. The report noted that benzene, GRO and DRO exceeded Table C levels at HC-1, and Table C levels for DRO at HC-2B. DEC requested that a monitoring plan be submitted for sampling events for fall 04 and spring 05. |
Rich Sundet |
| 10/14/2004 |
Update or Other Action |
CSP reviewed and approved the "Groundwater Monitoring Plan 1717 Tidewater Road" prepared by Horizon LLC's consultant HartCrowser dated October 2004. CSP received the plan on October 13, 2004. The plan was submitted in response to CSP’s September 23, 2004 letter to Horizons that requested groundwater sampling events to occur at the site in fall 2004 and spring 2005. |
Rich Sundet |
| 6/13/2005 |
Update or Other Action |
On 6/13/05, DEC issued a letter that it did not object to an Oasis 6/6/05 conceptual plan that proposed to remove USTs/piping and leave contamination in place after installing a bioventing system. |
Rich Sundet |
| 8/18/2005 |
Leaking Underground Storage Tank Corrective Action Underway |
On 8/18/05, DEC conditionally approved of Oasis' 7/11/05 plan to remove the 3 existing USTs and refill the excavation with clean material and removed contaminated soil between clean fill above the water table, and replace the existing bioventing system, and pave over the area.
DEC also commented on HartCrowser's 5/05 GW report that showed DRO, GRO and benzene still remained above Table C cleanup levels. DEC requested another sampling round in fall 05 and spring 06, and that MW HC-4 did not need to be resampled at that time. |
Rich Sundet |
| 8/22/2005 |
Update or Other Action |
On 8/22/05, DEC received Oasis "Fianl UST Removal WorkPlan, Terminal Facility, Port of Anchorage" dated 8/19/05 that incorporated comments provided by DEC on 8/18/05. |
Rich Sundet |
| 9/15/2005 |
Update or Other Action |
In September 2005, OASIS Environmental, Inc. (OASIS) oversaw the removal of the three
USTs and associated piping and dispensers. A soil sample collected from the north sidewall of the UST excavation at 7 feet bgs contained benzene at 0.302 mg/kg, ethylbenzene at 3.06 mg/kg, xylenes at 22.1 mg/kg, and DRO at 447 mg/kg. A soil sample collected 3 feet bgs underneath a fuel dispenser on the SE fuel island contained DRO at 3,170 mg/kg.Based on a plan discussed with the ADEC,Biennial Groundwater Monitoring and Biovent System Monitoring
Work Plan Horizon Lines, Inc.OASIS left visible petroleum contamination in place during the removal and placed contaminated soil back into the excavation above the water table (OASIS 2005, ADEC 2005). As part of the removal, two monitoring wells (MW-8 and MW-9) were installed at the down-gradient edges of the UST excavation. |
Grant Lidren |
| 6/7/2006 |
Document, Report, or Work plan Review - other |
On 6/7/06, CS provided comments regarding Oasis' 11/17/05 report "Tank Removal and Site Assessment Report, Terminal Facility Port of Anchorage." CS requested clarification and additional information on the bioventing replacement system as well as several other issues. The report had noted that USTs 4, 5 and 6 were removed in fall 2005, two groundwater monitoring wells installed, and a replacement bioventing system installed. Maximum contaminant levels remaining were up to 3,170 mg/kg DRO under the former southeast dispenser (PID results were similar for under the former northeast dispenser), and 447 mg/kg DRO and 0.302 mg/kg benzene under the area of former UST #4. |
Rich Sundet |
| 8/16/2006 |
Document, Report, or Work plan Review - other |
On 8/16/06, DEC provided comments to Oasis' 6/9/06 groundwater report and their 7/7/06 response letter. The 7/7 response was to DEC's 6/7/06 letter to Horizon Lines. DEC's 8/16 letter noted that the fall 05 and spring 06 data showed that DRO, GRO and BTEX exceeded Table C levels in the newly installed MWs 8 & 9 and for DRO, GRO and benzene in HC-1 (benzene was detected a max. at MW9 at 7.94 mg/L). DEC's 8/16 letter requested continued semi-annual groundwater monitoring, an evaluation of whether further downgradient wells need to occur to define the leading edge of the plume, a CSM, and workplan for the continued monitoring that would also include how Horizon plans to monitor the bioventing system over time. |
Rich Sundet |
| 9/14/2006 |
Long Term Monitoring Established |
On 9/14/06, CSP conditionally approved of Oasis' 9/6/06 longterm groundwater monitoring plan. The plan proposed semi-annual monitoring at selected wells on site including the additon of two new downgradient wells to define that extent of the contamination. Natural attenuation parameters would be collected to determine how clenaup progress is being made as well as information from the in-situ passive vapor venting system. |
Rich Sundet |
| 4/26/2007 |
Exposure Tracking Model Ranking |
Ranked site with ETM on 4/26/07. |
Rich Sundet |
| 6/26/2007 |
Document, Report, or Work plan Review - other |
On 6/26/07, CSP approved of Oasis' recommendations in their report "2007 Long-term Monitoring Report Port of Anchorage Horizon Lines of Alaska" dated May 2007. The report recommended continued semi-annual groundwater monitoring, reducing GRO/BTEX sampling from MWs HC-2B and HC-6, eliminate natural attenuation monitoring for at least one year, and continue to monitor the bioventing system on a semi-annual basis. The report also showed contaminant exceedances for petroleum constituents in all monitoring wells sampled (MW) (i.e., HC-1, HC-3, HC-6, HC-8, HC-9, HC-10 and HC-11) except MW-2B. Benzene ranged up to 7.42 mg/L (at MW-9). DEC noted that while contamination above some of the contaminants were detected in the new down-gradient monitor wells MW 10 and 11, it appears for the most part that the distil end of the plume has been identified unless there is an unknown preferential pathway in the area. The report concludes that generally contaminant levels have decreased other than in the area where the former USTs were located, i.e., MWs 8 and 9. The next groundwater events are scheduled for fall 2006 and spring 2007 at which time one report is anticipated to be prepared for findings of both events. |
Rich Sundet |
| 11/3/2008 |
Update or Other Action |
On 11/3/08, DEC responded to Oasis' report titled “2008 Long-Term Monitoring Report (Year 2) Port of Anchorage Terminal Facility” dated June 2008 for the Horizon Lines Facility at the Port of Anchorage. DEC received the report on June 17, 2008. The report provided information on the results of activities performed since fall 2007 including groundwater sampling events in October 2007 and April 2008, as well as monitoring data from the on site bioventing system. The June 2008 report showed that eight monitoring wells were sampled in October 2007 (i.e., HC-1, HC-2B, HC-3, HC-6, HC-8, HC-9, HC-10 and HC-11). Seven of those wells were sampling in April (MW-11 was not sampled) but two of the wells were only sampled for DRO (HC-2B and HC-6). Contaminant exceedances for petroleum constituents were detected in monitoring wells sampled at HC-1, HC-2B, HC-6, HC-8, and HC-9. Benzene ranged up to 8.16 mg/L (at MW-9). Similar to past data, MWs 8 and 9 showed the most frequent detections over applicable cleanup levels in 18 AAC 75.345. Because of the past findings, the report recommends: a reduced sampling frequency of all monitoring wells to an annual basis to occur in October; elimination of MW-10 from further sampling events; and eliminate sampling for GRO/BTEX at MW-11. The report also proposed a sampling scheme in Section 6. Therefore, the report noted that the next sampling event would occur in October 2008 and a report would be prepared in December 2008. In DEC's 11/3/08 letter it noted that it had no objection to Horizon implementing the proposed sampling scheme provided that the annual reports be be submitted to DEC by March 31 each year; natural attenuation parameters will also need to be sampled for in October 2009 if not done so already for the October 2008 event; and operation and monitoring of the existing bioventing system will continue.
|
Rich Sundet |
| 11/17/2008 |
Update or Other Action |
On 11/17/08, Sundet granted verbal approval to Ben Martich of Oasis regarding his request via the telephone to change the annual groundwater monitoring from fall to spring. This was followed-up in an email exchange between Sundet and Martich. |
Rich Sundet |
| 11/23/2009 |
Site Characterization Report Approved |
On this date, ADEC received the 2009 Long-Term Monitoring Report Port of Anchorage Terminal Facility dated November 2009 submitted by Oasis. Monitoring wells HC2B, HC-6, and MW-11 (not sampled for BTEX & GRO) did not contain detectable concentrations of DRO above cleanup levels. HC-1, HC-3, MW-8 and MW-9 contained petroleum constituents above ADEC cleanup levels. MW-8 was most contaminated with benzene at 2.41 mg/L, toluene at 4.35 mg/L, ethylbenzene at 2.06 mg/L, xylenes at 15.3 mg/L, GRO at 101 mg/L, and DRO at 25.4 mg/L. Additionally, MW-8 was the only MW to contain toluene, ethylbenzene, and xylenes above ADEC cleanup levels. The GW flowed to the south. |
Grant Lidren |
| 1/5/2011 |
Site Characterization Report Approved |
On this date, ADEC received the 2010 Long-Term Monitoring Report Port of Anchorage Terminal Facility dated January 5, 2011 submitted by Oasis. Monitoring wells HC-3 (not sampled for BTEX & GRO) and HC-6 did not contain petroleum constituents above cleanup levels. HC-1, MW-8, and MW-9 contained petroleum constituents above ADEC cleanup levels. MW-8 was most contaminated with benzene at 1.82 mg/L, toluene at 2.28 mg/L, ethylbenzene at 2.38 mg/L, xylenes at 19.9 mg/L, GRO at 98.1 mg/L, and DRO at 21.5 mg/L. Additionally, MW-8 was the only MW to contain toluene, ethylbenzene, and xylenes above ADEC cleanup levels. The GW flowed to the south. |
Grant Lidren |
| 1/4/2012 |
Site Characterization Report Approved |
On this date, ADEC received the 2011 Long-Term Monitoring Report Port of Anchorage Terminal Facility dated January 4, 2012 submitted by Oasis. Monitoring well HC-6 (not sampled for BTEX & GRO) did not contain petroleum constituents above cleanup levels. Monitoring well HC-4 did not contain detectable concentrations of petroleum constituents. HC-1, HC-3, MW-8, and MW-9 contained petroleum constituents above ADEC cleanup levels. MW-8 was most contaminated with benzene at 1.84 mg/L, ethylbenzene at 1.84 mg/L, xylenes at 14.1 mg/L, GRO at 59.6 mg/L, and DRO at 20.4 mg/L. Additionally, MW-8 was the only MW to contain ethylbenzene, and xylenes above ADEC cleanup levels. The GW flowed to the south. |
Grant Lidren |
| 10/10/2013 |
Site Characterization Workplan Approved |
On this date, ADEC received the Biennial Groundwater Monitoring and Biovent
System Monitoring Work Plan submitted by ERM dated October 10, 2013. The bioventing system will be monitored and Monitoring wells: HC-1, HC-3, HC-6, MW-8, and MW-10 will be sampled. The biennial sampling will occur in 2013, 2015, and 2017.
|
Grant Lidren |
| 12/18/2013 |
Site Characterization Report Approved |
On this date, ADEC received the 2013 Long-Term Monitoring Report Port of Anchorage Terminal Facility submitted by ERM dated December 2013. The bioventing system was monitored and monitoring wells: HC-1, HC-3, HC-6, MW-8, and MW-10 were sampled. All the MWs sampled except HC-3 contained petroleum constituents above ADEC cleanup levels. MW-8 was most contaminated with benzene at 1.43 mg/L, ethylbenzene at 1.63 mg/L, xylenes at 12 mg/L, GRO at 27.4 mg/L, and DRO at 17.7 mg/L. Additionally, MW-8 was the only MW to contain ethylbenzene, and xylenes above ADEC cleanup levels. The GW flowed to the south. |
Grant Lidren |
| 1/8/2016 |
Site Characterization Report Approved |
On this date, ADEC received the 2015 Long-Term Monitoring Report Port of Anchorage Terminal Facility submitted by ERM dated December 2015. The bioventing system was monitored and monitoring wells: HC-1, HC-3, HC-6, MW-8, and MW-10 were sampled. MWs HC-3 and HC-6 contained DRO at 2.5 mg/L and 2.8 mg/L respectively. HC-1 contained benzene at 1.1 mg/L, GRO at 3.8 mg/L, and DRO at 7.5 mg/L. MW-8 contained benzene at 2.3 mg/L, ethylbenzene at 2.0 mg/L, xylenes at 13.0 mg/L, GRO at 61.0 mg/L, and DRO at 23.0 mg/L. Additionally, MW-8 was the only MW to contain ethylbenzene, and xylenes above ADEC cleanup levels. The GW flowed to the south. |
Grant Lidren |
| 1/5/2018 |
Site Characterization Report Approved |
On this date, ADEC received the 2017 Long-Term Monitoring Report Port of Anchorage Terminal Facility submitted by ERM dated January 2018. The bioventing system was monitored and monitoring wells: HC-1, HC-3, HC-6, MW-8, and MW-9 were sampled. MWs HC-3 and HC-6 did not contain contaminant concentrations above Table C cleanup levels. HC-1 contained benzene at 0.7 mg/L, ethylbenzene at 0.094 mg/L, and DRO at 5.1 mg/L. MW-8 contained benzene up to 1.5 mg/L, ethylbenzene up to 1.7 mg/L, xylenes up to 12.0 mg/L, GRO up to 36.0 mg/L,DRO up to 13.0 mg/L, naphthalene up to 0.14 mg/L, and 1-methylnapthalene up to 0.024 mg/L. MW-9 contained benzene at 0.73 mg/L, ethylbenzene at 0.19 mg/L, and DRO at 7.0 mg/L. The GW flowed to the south. |
Grant Lidren |
| 6/4/2019 |
Site Visit |
Site visit on this date with Matson. Most all monitoring wells were located with the exception of HC-3 and MW-10. Letter sent to Matson for further action. |
Grant Lidren |
| 7/22/2019 |
Site Characterization Workplan Approved |
On this date, ADEC approved the Revised Groundwater Monitoring and Passive Bioventing System Monitoring Workplan submitted by BGES and dated July 18, 2019. |
Grant Lidren |
| 12/17/2019 |
Site Characterization Report Approved |
ADEC received the 2019 Groundwater Monitoring and Passive Bioventing Monitoring Activities submitted by BGES and dated December 2019. The bioventing system was monitored and monitoring wells: HC-1, HC-3, HC-4, HC-5, HC-6, MW-8, and MW-9 were sampled. MWs: HC-3, HC-4, HC-5, and HC-6 did not contain contaminant concentrations above Table C cleanup levels. HC-1, MW-8 and MW-9 contained contaminant concentrations above cleanup levels with DRO up to 6.1 mg/L, GRO up to 8.62 mg/L and three PAHs and seven VOCs above Table C cleanup levels. HC-6 contained only chloroform above ADEC cleanup levels at 11.4 ug/L. The GW flowed to the south. |
Grant Lidren |
| 12/30/2019 |
Document, Report, or Work plan Review - other |
On this date, ADEC received the Environmental Management Plan, 1717 Tidewater Road submitted by Shannon & Wilson and dated December 26, 2019. A broken water line will be replaced and soil and groundwater will need to be removed and discharged during the project. Preliminary sampling was conducted in December 2019 to characterize potential contaminants in soil and groundwater. A grab groundwater sample from a dug pothole and collected from a bailer contained benzene up to 11.4 ug/L. Two soil samples collected from 4.0 feet bgs and the groundwater interface at 6 feet bgs contained benzene up to 0.0797 mg/kg and naphthalene up to 0.0538 mg/kg. During the project, suspected contaminated soil will be excavated and transported to ASR and excavation water will be discharged into the sanitary sewer. |
Grant Lidren |
| 8/5/2020 |
Site Characterization Report Approved |
On this date, ADEC received the Soil and Groundwater Handling Report, 1717 Tidewater Road submitted by Shannon & Wilson and dated August 5, 2020. In November 2019, a waterline broke located at the 1717 Tidewater Road Matson Building and contaminated soil/groundwater was encountered. Prior to repair work, a grab groundwater sample collected from a pothole excavation contained benzene at 11.4 ug/L above Table C groundwater cleanup levels. Additionally, a test pit was advanced west of the building and the vicinity of the waterline to a depth of 8 feet bgs. Groundwater was encountered at 6 feet bgs. Two soil samples collected: one at 4.0 to 4.5 feet bgs and one at 6.0 to 6.5 feet bgs. The soil sample collected at 4.0 to 4.5 feet bgs contained detectable concentrations of contaminants, but below cleanup levels. The soil sample collect 6.0 to 6.5 feet bgs contained naphthalene up to 0.0538 mg/kg and benzene up to 0.0797 mg/kg above method two MTG cleanup levels. During excavating, 2,300 gallons of water was removed. A water sample collected from the 2,300 gallons of water stored in a weir tank prior to discharge into the sanitary sewer contained arsenic at 3.07 ug/L and benzene at 27.7 ug/L. Soil was excavated to a depth of 11 feet bgs during replacement of the water line which was located 10 feet bgs. Elevated pid readings and petroleum smell were noted starting at 1.5 feet bgs and generally increased with depth. The highest pid reading of 537 ppmv was noted at 7 to 9 feet bgs. Significant soil contamination was noted throughout the excavation at the groundwater interface. Approximately 560 cubic yards of contaminated soil was transported to ASR for thermal remediation. After repair work was completed, clean fill was placed around the pipe. The overburden excavated material to a depth of 1.5 feet bgs (assumed clean based on olfactory, visual, and low pid readings (less than 20 ppm)) was then put back into the excavation. The excavation was then brought to grade with clean fill. |
Grant Lidren |
| 10/27/2020 |
Offsite Soil or Groundwater Disposal Approved |
DEC approved off-site transport of 20 cubic yards of contaminated soil to ASR. The soil was generated during excavation associated with the kiosk lane concrete slab at the Matson Facility. The excavation occurred west of 1917 Tidewater Road in the middle of the Matson yard. DRO was present at 404 mg/kg. |
Janice Wiegers |
| 3/5/2021 |
Document, Report, or Work plan Review - other |
DEC reviewed and approved workplan for evaluation of vapor intrusion at the Matson Facility. BGES plans to collect indoor and outdoor air samples near the end of April. The work plan is dated 2/3/2021. Additional soil and groundwater investigation is expected in the summer. |
Janice Wiegers |
| 6/2/2021 |
Document, Report, or Work plan Review - other |
On this date, ADEC received Matson Port of Anchorage 1717 Tidewater Road Anchorage, AK Evaluation of Vapor Intrusion Report, dated May 2021. Indoor and outdoor ambient air samples were set up on March 30, 2021 and retrieved on March 31, 2021 for the collection of indoor and outdoor ambient air samples over a 24-hour sampling period to evaluate the potential vapor intrusion pathway at the Matson office building. Three indoor ambient air samples (including one duplicate) were collected from two offices located within the northwestern section of the building and one outdoor ambient air sample was collected from the roof of the building. The locations for collection of these samples were selected, because they were the most likely areas where vapor intrusion would potentially occur because they were positioned within offices that were located closest to the soil and groundwater contamination identified near the northwestern building corner. All indoor/outdoor ambient air samples exhibited analyte concentrations below the ADEC
target levels for indoor air for commercial properties. |
Brandi Tolsma |
| 9/27/2021 |
Update or Other Action |
DEC approved the approach for monitoring the groundwater and bioventing system for BGES to complete this fall. |
Janice Wiegers |
| 11/23/2021 |
Document, Report, or Work plan Review - other |
On this date, ADEC approved work plan to conduct site characterization work for the property located at 1717 Tidewater in Anchorage. The work plan proposes advancing three soil borings that will be completed as monitoring wells to define the extent of soil and groundwater contamination at the subject property. Soil and groundwater samples will be analyzed for diesel range organics (DRO), gasoline range organics (GRO), residual range organics (RRO), and volatile organic compounds (VOCs). Additionally 10% of soil and groundwater samples will be submitted for analysis of polycyclic aromatic hydrocarbons (PAHs). |
Brandi Tolsma |
| 3/25/2022 |
Document, Report, or Work plan Review - other |
On this date, ADEC received the Matson Port of Anchorage Evaluation of Vapor Intrusion Report. This report details the September 2021 vapor intrusion investigation conducted at the Matson office building to evaluate potential seasonal patterns. Three indoor ambient air samples (including a duplicate sample) were collected from inside the building and one outdoor ambient air sample was collected from the roof of the building. The indoor/outdoor ambient air samples were analyzed for volatile organic compounds (VOCs) by Modified Environmental Protection Agency (EPA) Method TO-15. All four samples exhibited concentrations of analytes that were below the DEC target levels for indoor air for commercial properties. |
Brandi Tolsma |
| 5/16/2022 |
Document, Report, or Work plan Review - other |
On this date, ADEC received the 1717 Tidewater Road Anchorage 2021 Groundwater Monitoring and Passive Bioventing Monitoring Activities Report. This report details the November 2021 monitoring activities conducted at 1717 Tidewater Road in Anchorage, Alaska. Five monitoring wells (MW8, MW9, MW10, HC1, HC6) were sampled for gasoline range organics (GRO), diesel range organics (DRO), volatile organic compounds (VOCs), and polynuclear aromatic hydrocarbons (PAHs). Groundwater elevations were collected and used to determine groundwater flow direction. Additionally, the passive biovent system was monitored at vent lines V1, V2, V3, V5, and V6.
Due to the exceedances in groundwater DEC recommends further groundwater monitoring of wells MW8, MW9, MW 10, and HC1 until the contaminated groundwater plume can be shown to be stable and the groundwater concentrations decreasing.
The monitoring results from the passive bioventing system indicated that aerobic biodegradation of volatile hydrocarbons is ongoing for soils located within the former UST system excavation. DEC recommends further monitoring of the bioventing system. |
Brandi Tolsma |
| 4/10/2023 |
Update or Other Action |
Site characterization report submitted by BGES. |
Janice Wiegers |
| 10/6/2023 |
Site Characterization Report Approved |
On October 6, 2023 Alaska Department of Environmental Conservation (DEC) approved the report titled Site Characterization Activities Report Matson Office Building 1717 Tidewater Road Anchorage, AK. The report details the June and July 2022 site investigation conducted at the Matson office building to evaluate the extent of groundwater contamination on the property. Three soil borings were advanced and completed as monitoring wells. The hydraulic gradients of the monitoring wells were collected to determine groundwater flow direction. Four soil and four groundwater samples (each including a duplicate sample) were collected for analysis. Contamination was identified in concentrations exceeding DEC cleanup levels in soil samples taken from soil borings SB2 and SB3, and from groundwater samples taken from monitoring wells MW2 and MW3. The soil contaminants above DEC cleanup levels include GRO, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, benzene, ethylbenzene, hexachlorobutadiene, isopropylbenzene, n-propylbenzene, naphthalene, toluene, total xylenes, 1-methylnaphthalene, and 2-methylnaphthalene. The groundwater contaminants above DEC cleanup levels include GRO, benzene, and ethylbenzene.The DEC provided comments that further site investigation is required to delineate the horizontal extent of the contamination to the west, north, and east. A workplan for additional characterization and to define the source of the contamination was also requested. DEC concurred with the environmental consultant’s recommendation that the monitoring wells MW2 and MW3 where contaminant concentrations exceeded ADEC cleanup levels be resampled in the spring or summer of 2024 to evaluate seasonal contaminant variability.
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Mollie Dwyer |
