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r �i Mr Kenneth Earnest December 5, 1994 Page 3 Soil generated during the advancement of the soil borings was stockpiled on site on plastic and covered with plastic pending characterization for disposal One composite soil sample was collected from the stockpiled soil and submitted for analysis of BTEX, TPHg, and TPHd Analytical results are compiled in Table 3 Vapor Extraction Well Installation Vapor extraction wells VE-1 through VE-3 were constructed of 2-inch-diameter, Schedule 40 PVC casing Prior to well installation, soil borings SB-1, SB-2, and SB-5 were backfilled from 44 feet below grade to the total depth of each boring with bentonite chips that were hydrated using 5 gallons of water per sack of bentonite chips (Enclosure B) Each well was then constructed with 10 feet of 0 020-inch slot PVC well screen emplaced from 34 to 44 feet below grade Vapor extraction well construction details are contained in Enclosure D Copies of field observations and data sheets from work performed at the site from September 26 through 29, 1994, are presented in Enclosure E Monitoring Well Replacement Ground water monitoring well MW-7, which contained an obstruction in the casing at approximately 73 Leet below grade, was removed and replaced on September 28, 1994 Attempts to remove the 4-inch- diameter casing intact using the hydraulic hoist on the drilling truck were unsuccessful All well . construction materials including the casing, well screen, filter pack, bentonite and sanitary seal were removed from the borehole using a drilling truck equipped with 10-inch outside-diameter hollow-stem augers Monitoring well construction details for the newly installed well are provided in Enclosure F The depth to ground water in the new monitoring well MW-7 was measured on September 28, 1994, and was recorded at 72 77 feet below the top of the casing Summary of Analytical Results Soil samples collected from soil borings SB-3 through SB-6 did not contain detectable amounts of BTEX, TPHg, or TPHd Soil samples collected at 35 and 40 feet below grade from soil boring SB-2 contained TPHg concentrations of 210 and 630 mg/kg, respectively Benzene was not detected in any of these samples above 0 050 mg/kg Soil samples collected from soil borings SB-1 and SB-2 contained TPHd concentrations ranging from less than detectable levels to 6,600 mg/kg As indicated in Table 6, benzene was not detected above the method detection limit in the TCLP extracted liquid Concentrations of TPHg and TPHd were reported at 2,600 and 55 )ug/l, respectively ACTON • UrtW7 ssb MICKELSON- van DAM,INC Consulting Scientists, Engineers,and Geologists