ARCHIVED REPORTS XR0010934 - Laserfiche WebLink

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1.0 EXECUTIVE SUMMARY i In October, 1992, during the removal of three underground storage tanks, diesel constituents were discovered in the soil at the Derickson Trucking site, Escalon, California. Soil samples collected from beneath two of the tanks were reported as non-detect for all hydrocarbon constituents analyzed; however, soil samples collected beneath the 12,000 gallon diesel tank indicated the soil had been impacted by diesel hydrocarbons. A Site Characterization conducted by AquaGeosciences Inc. (AGI) delineated a plume with an approximate aerial extent of 550 square feet. The vertical extent of the plume was estimated to be in excess of 30 feet. The highest concentrations reported for benzene and Total Petroleum Hydrocarbons (TPH) as diesel were 7.9 and 4100 ppm, respectively. Due to the proximity of the contaminated mass to the groundwater table (approximately at 90 feet below the surface and historically as high as 50 feet), remedial action was recommended. This report documents the excavation of the contaminated soil and its subsequent - bioremediation on the east side of the property in a bermed treatment cell. Chemical analyses of soil samples collected from the walls and base of the excavation confirm h the removal of all detectable diesel hydrocarbon impacted soils at the site. Bioremediation of excavated soil is deemed complete based on the analytical results of eight composite soil samples. The analytical results for BTEX were all non-detect and TP.H diesel ranged from non-detect to 32 ppm. 2.0 BACKGROUND The Derickson Trucking site is located at 315 15658 S. Escalon-Bellota Road in Escalon, California (Exhibit 1). The property is owned by Mr. Dave Derickson of Escalon, California and the property is leased to Mid-Valley Agriculture. 2.1 Facility Description ) Derickson Trucking is located off of Escalon Bellota Road, approximately 20 miles north of Modesto and 2.miles north of Escalon. The facility consists of 2 large warehouses which lie side by side and a trucking scale which lies along the south side of these buildings. The rest of the site is a paved and graveled parking lot which is presently being used by Mid-Valley Agriculture to store mobile and stationary fertilizer tanks. Three underground storage tanks (USTs) were formerly located on the property. One 2,000 gallon gasoline tank and a 12,000 gallon diesel tank and associated dispenser were located in the front on the the west side of the property near S. Escalon Bellota Road. A 2,000 gallon waste oil tank was located on the east side of the northernmost warehouse. The former dispenser island was situated north of the tank location. A plot plan of the property is provided on Exhibit 2. 2 of 9 i