Spill Response
In June 2007, a diesel release occurred from an aboveground storage tank (AST) located at a property in Fairfax, Vermont. The pump reportedly malfunctioned and released approximately 2,000 gallons of diesel. A sensitive receptor survey determined that soils surrounding the AST on the property were impacted, several bedrock outcroppings were observed and impact to the neighboring property (the field) was apparent. A brook was located at the base of the field approximately 770 feet downgradient of the spill. Verterre inspected the brook for diesel contamination and found no evidence of product impact.
Product collection trenches were installed in the spill pathway and product recovery booms and pads were placed in all of the trenches. Contaminated soils were excavated from the property and stockpiled on 6 Mil polyethylene. During the excavation, bedrock folds in the spill pathway were sealed with bentonite clay. Approximately 1,400 yards of soil were excavated from the property and polyencapsulated on Site. Another 410 yards of contaminated soil were excavated from the field area and stockpiled with the other soils.
Silt fencing was installed around the interception trench system in the field for erosion control. Saturated booms and pads in the trenched areas of the field were changed on an as needed basis. Verterre personnel inspected properties abutting the field and observed that numerous supply wells were present. Due to the presence of bedrock at the ground surface in the spill pathway and the potential for bedrock contamination, Verterre contacted the State of Vermont and the Town of Fairfax regarding these wells. The neighboring supply wells were sampled and no volatile organic compounds (VOCs) were reported above the method detection limits (MDLs) in any of the samples.
Between July and August 2007, a total of 9,620 tons of stockpiled soils and excavated soils from the neighboring field were loaded and disposed of at a lined landfill. Limits of contamination in the field were defined using PID, olfactory and visual observations. A total of twenty-six confirmatory soil samples were collected for VOCs and TPH-DRO. No contaminants of concern (COCs) were reported above the MDLs in any of the confirmatory samples. The excavation area was backfilled with clean fill and compacted with a bulldozer during the backfilling process. During excavation activities, frequent reconnaissance of the brook and drainage tilings was conducted. No sheens or product were observed in any of the tilings or the brook. Monitor wells and two bedrock wells were installed. The monitor wells, neighboring supply wells, the bedrock wells, the brook and drainage tilings were all sampled and COCs were not reported above the Vermont Groundwater Enforcement Standard (VGES).