Division of Spill Prevention and Response

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Sand Lake Services


Incident location map. Summary Date: May 2003 View detailed information from database on this site.arrow
Status: Active Database Name: Sand Lake Car Wash & Gas Station
Location: 7211 Jewel Lake Rd., Anchorage, AK Latitude/Longitude: See database entry
DEC Contaminated Sites Contact: Robert Weimer, Project Manager - 907-269-7525

Description

 

The Sand Lake Services site is located at 7211 Jewel Lake Road, Lot 1A, Hansen Sand Lake Subdivision, Section 2, Range 4 West, Township 12 North, Seward Meridian, Anchorage, Alaska. The site is a gasoline service station and garage, with an adjoining car wash facility. Municipal water supply and sewer systems serve the property.


At the time of the release investigation, the underground storage tank system (USTs) consisted of four USTs and four fueling islands that contained nine fuel dispensers. In May 1995, the former UST fueling system (one 10,000 gallon gasoline tank, one 5,000 gallon gasoline tank, and one 2,000 diesel tank) was removed and replaced with two new 12,000 gallon USTs, and new fuel islands with double walled piping. A 1,000 gallon waste oil UST located adjacent to the southeast corner of the garage was removed between May 30 and June 6, 1997.


During March 1992, there was a gasoline spill on the site originating from the second dispenser from the south on the western fuel island. The 1992 spill was approximately 90 gallons, with most of the product spilled onto the pavement and then flowing down in to an adjacent ditch. A similar event occurred in 1976 from the north dispenser of the southeast island. The owner estimated that 50 to 100 gallons spilled onto unpaved ground at that time. During the excavation of the former USTs, ground surface staining was observed, and a sheen on the water seeping into the excavation between the 5,000 gallon and 10,000 gallon USTs.


The contaminated soil removed from the UST excavation was placed in a secured stockpile located on the property near the southeast corner of the gas station. The contaminated soil was placed on a 10 mil reinforced visqueen liner and covered with 10 mil reinforced visqueen. The stockpile contained approximately 5 cubic yards of contaminated soil.


Release Investigation (dated September 26, 1995) During July 1995 a release investigation was performed which consisted of drilling three test borings. The soil samples collected from Test Boring 3 contained high levels of diesel and gasoline range petroleum hydrocarbons, benzene, and total Benzene, Toluene, Ethylbenzene, Xylene (BTEX). Also, the water sample collected from TB-3 had a high level of benzene and BTEX contamination above the Department of Environmental Conservation (DEC) clean up levels.


Site Assessment Report (dated August 22, 1997)
The purpose of the site assessment was to investigate the contamination caused by past spills from a 1,000 gal waste oil UST and associated product piping during removal/closure of the UST system. Water seeped into the UST excavation at approximately 4.0 feet below the ground surface from the northeast and southeast corners of the excavation. Soil staining was observed in the excavation sidewalls. One sample was collected and was above cleanup levels for Gasoline Range Organics (GRO) 270 mg/kg, Diesel Range Organics (DRO) 7,360 mg/kg, and Residual Range Organics (RRO) 1,230 mg/kg. A single 5 cubic yard stockpile of contaminated soil was created as a result of the UST removal.


Phase I Release Investigation (dated April 10, 1998)
The purpose of the Phase I Release Investigation was to delineate soil and groundwater contamination by installing 3 groundwater monitoring wells. One was installed upgradient of the former USTs, and two to the south. GRO concentration above cleanup levels was identified in the soil at G-2. DRO and benzene concentration above the cleanup levels was identified in the soil at G-2 and G-3. MW G-2 was dry at the time of sampling. GRO and benzene concentration above cleanup levels was identified in wells G-1 and G-3.


Phase II Release Investigation (dated October 22, 1999)
The purpose of the Phase II Release Investigation was to further characterize and delineate contamination caused by past spills from the former USTs. Field activities involved drilling one additional soil boring and construction of a groundwater monitoring well, and collecting soil and groundwater samples. In boring G-4, concentrations were above the Category A Cleanup level for benzene. The water quality in the monitoring wells are as follows, G-1, G-2, G-3, and G-4 were all above the cleanup level for benzene. Monitoring wells G-2 and G-3 were above cleanup level for GRO. Monitoring well G-2 was above cleanup level in the groundwater samples for DRO.


Release Investigation and Monitoring Event April 2001 (dated June 4, 2001)
The purpose of the Release Investigation and monitoring was to further delineate the extent of contamination in soil at the site. Six monitoring wells were installed (G-5, G-6, G-7, G-9 and G-10). Soil boring samples above cleanup levels for benzene were MW G-8 at 5 ft/bgs, and MW G-9 at 15 ft/bgs.


Groundwater results above the DEC Table C cleanup levels
Monitoring Well ID Benzene Toluene Ethylbenzene Total Xylenes GRO DRO RRO Chromium Lead
G-1 0.00719                
G-2 18.6 36.0 2.64 13.11 138 25.6 4.5    
G-3 1.13 2.52     11.2        
G-4 0.561       2.85        
G-5 0.0719                
G-6 0.0063                
G-8               0.175 0.0333

 

January 2002 Monitoring Event (Groundwater) (dated January 25, 2002)
The January 2002 monitoring event report provided the groundwater monitoring results for the sampling event conducted on January 10, 2002 which included wells G-1, G-2, G-3, G-4, G-5, G-6, G-7, G-8, G-9 and G-10. Monitoring wells G-1, G-3, G-4, G-5 were above cleanup level for benzene. Monitoring well G-3 was above for Toluene. Monitoring wells G-3, G-4, and G-5 were above for GRO, and monitoring well G-1 was above for RRO. Contamination is present in the groundwater near the dispenser islands and near wells G-3 and G-4.


April 2002 Monitoring Event (Groundwater) (dated May 14, 2002)
Groundwater monitoring results for the sampling event conducted on April 25, 2002. Monitoring wells G-1, G-5, G-7, G-8, G-9, and G-10 were all sampled for BTEX, GRO and DRO. Monitoring well G-5 showed 0.0305 mg/kg Benzene which is above cleanup levels.

 


Public Health and Environmental Concerns

 

The contaminants of concern (COCs) are BTEX, GRO, DRO, RRO, chromium, and lead. Groundwater on site is contaminated. Drinking water wells are present within ¼ of a mile from the site. A well search was performed during June 2002. DEC has requested that drinking water wells in the area be sampled for benzene, toluene, ethylbenzene, xylene, DRO, GRO, RRO, and Drinking Water Method EPA 524.2.

 


Current Status

 

Long term quarterly groundwater monitoring, groundwater slug testing, Pilot Test for Vapor Stripping, and Circulation System.