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1 EXECUTIVE SUMMARY f'■ KLEINFELDER This report presents results for the installation of three monitoring wells, and initial sampling and laboratory analysis. The installation of the monitoring wells was conducted according to Kleinfelder's proposal titled "Additional Soil and Groundwater Investigation, Tradeway Chevrolet", dated April 29, 2002. The proposal was developed and implemented at the request of AKF Development, LLC for the purpose of evaluating potential impact to groundwater due to elevated concentrations of Total Petroleum Hydrocarbons as diesel (TPH-d) and Total Petroleum Hydrocarbons as motor oil (TPH-mo) detected at the site at the subject site. Three monitoring wells were installed on May 20, 2002 and designated MW -1, MW -2, and MW -3. On May 23, 2002 the newly installed monitoring wells were developed. Kleinfelder re -visited the site on May 28, 2002 to conduct the initial sampling event. An elevation survey of the three monitoring wells MW -1, MW -2, and MW -3 was also conducted on June 5, 2002. The groundwater flow direction was calculated to be to the northwest with a gradient of 0.0033 feet/foot at the site. Soil samples were collected from the soil borings and were analyzed for TPH-g, benzene, toluene, ethylbenzene, and xylene (BTEX), Oxygenates (MTBE, TAME, DIPE, and ETBE, methanol), and Total Extractable Petroleum Hydrocarbons (Fuel Fingerprint). There were no detected concentrations of any of the previously listed analytes in the soil samples submitted for laboratory analysis. Groundwater samples were analyzed for TPH-g, BTEX, MTBE, TAME, DIPE, and ETBE, methanol, and Fuel Fingerprint. Of the analytes that have established water quality goals (WQGs), only benzene was found to exceed the WQGs in one groundwater sample (MW -2) with a concentration of 1.5 ug/l. The Maximum Contaminant Level (MCL) for benzene is 1.0 ug/l. Toluene, ethylbenzene, and xylene were also detected in the same groundwater sample collected from MW -2 with concentrations of 1.6 ug/l, 1.3 ug/1, and 8.3 ug/l respectively, but did not exceed the WQGs for those analytes. Monitoring well MW -2 is located upgradient to the hydraulic lifts and service area. Methanol was detected in -one groundwater sample (MW -1) with a concentration of 110 ug/l. There is no MCL established for methanol. There is however a taste and odor threshold WQG of 740,000 ug/l for methanol. It should be noted that MW -1 is located downgradient to the hydraulic lifts and service area in question for this investigation. There were no detectable constituents in the groundwater sample obtained from MW -3 (downgradient from the former hydraulic lift leak). There has not been any subsurface evaluations to the upgradient or east of MW -1 and MW -2 in previous investigations on the site. Kleinfelder recommends that a geoprobe operation be undertaken to evaluate the extent of contamination. Additionally, Kleinfelder recommends that a 20-3978-03.CHEV / ST02RI I I Page 1 of 18 Copyright 2002, Kleinfelder, Inc. July 1, 2002