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kn KLEiNFELDER The concentration of xylene detected in the sample from MW-3 is below the DHS Action level of 620 ug/l. The concentration of EDB detected in the sample from MW-3 is only 0.10 ug/l above the DHS Action level of 0.020 ug/l The concentration of TPH detected in ' a soil sample from MW-3 within 1 foot of the top of the ground water is approximately 2,400 times greater than the concentration of TPH detected in the ground water sample ' from MW-3 ' We believe the origin of the ground water contamination at MW-3 may be from a leaking underground pipe or its connection to the underground storage tank Because the ' contamination levels are relatively low and benzene was not detected, no immediate remediation of the ground water is recommended at this time, but another round of ground water sampling is recommended. Fecal coliform was detected in the ground water samples with concentrations of ' 170 MPN/100 ml in MW-1, 5 MPN/100 ml in MW-2, and 13 MPN/100 ml in MW-3 Total coliform was detected in the ground water samples with concentrations of 170 MPN/100 ml in MW-1, 23 MPN/100 ml in MW-2, and 27 MPN/100 ml in MW-3 The highest concentration of total and fecal coliform was detected in the sample from MW-1 MW-3 is ' approximately 30 feet from the onsite sewage line, MW-2 is approximately 68 feet, and MW-1 is approximately 48 feet MW-3 is downgradient from the sewage line and MW-1 is upgradient. In view of the ground water gradient observed at the site, if the onsite sewage line were leaking, a higher concentration of coliform would be expected in the sample from MW-3 and not MW-1. It appears another source may be contributing to the high ' concentration of coliform at MW-1 A possible source for the higher contamination in the sample from MW-1 would be from an abandoned leach field A dark clayey material was ' encountered while drilling MW-1. This material had a hydrocarbon odor and appears similar to leach field material encountered during other site investigations. This material ' was also detected at MW-2 and MW-3. In any case, the presence of coliform bacteria is probably not associated with the operational history of the filling station 5 3 HYDROGEOLOGY Free water was encountered at an elevation of approximately 22 feet (MSL) or approximately 5 to 6 feet below ground surface. The free water is associated with the coarser gramed soils beneath the silty clay and does not appear to be confined. The ' 145-88-2013 8