WORK PLANS - Laserfiche WebLink

Home Browse Search

r On January 30, 1991, WaterWork Corp. published a Problem Assessment Report for Investigation of Petroleum Hydrocarbon Contamination, which documented the drilling of four soil borings (SB-1, SB-2, SB-3 and SB-4) and the installation of one groundwater monitoring well (MW-1). Results of the soil and groundwater sampling indicated that groundwater had been impacted by gasoline hydrocarbons, and that the majority of the hydrocarbon mass was concentrated in soil between 10 and-20 feet bgs. On July 9, 1992, Resna published their Summary Report—Assessment of Petroleum Hydrocarbon Contamination of the Groundwater, which documented the installation of two additional groundwater monitoring wells (MW-2 and MW-3). .. On July 8, 1994, Resna published Summary Report/Additional Groundwater Investigation, which documented the installation of two additional groundwater monitoring wells (MW-4 and MW-5). Gasoline hydrocarbons were not detected in groundwater collected from these two new wells. By January 1996, a rise in the groundwater table elevation had exceeded the top of the screen i.� interval in all five groundwater monitoring wells and had entered the screen interval of the two deeper soil vapor extraction wells (VW-1 D and VW-2D). On May 20, 1998, Ramage Environmental published Problem Assessment Report and Corrective Action Plan, which documented the installation of two additional groundwater monitoring wells (MW-6 and MW-7). L On November 28, 2000, Ramage Environmental published Environmental Site Investigation Report, which documented the drilling of confirmation soil borings (CPT-1 and CPT-1A). To confirm the effectiveness of remediation efforts, soil samples were collected every 10 feet. The soil sample results indicated that except for 560 mg/kg of TPH-as-gasoline in soil at a depth of approximately 10 feet bgs, the vadose zone soil was effectively remediated by the SVE system. In groundwater, concentrations of MTBE declined significantly with depth and were absent in the 125-foot groundwater-bearing interval. Only 1,2-DCA was detected in the 125-foot groundwater sample, at a low concentration of 0.5 µg11. On May 2, 2002, Ramage Environmental published Report, Additional Site Investigation, which documented the drilling of CPT borings for discrete groundwater sampling at six additional locations, and the installation of a two-well monitoring well cluster(MW-8A and MW-86). The results of the project indicated that the extent of MTBE was defined and limited to the groundwater table northeast (downgradient) of the former UST. Only low concentrations (0.5 to 1.2 µg11) of 1,2-DCA were detected in the 110 to 125 foot groundwater-bearing interval. 22