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_ r <br /> E <br /> Harding Lawson Associates <br /> VI DISCUSSION AND CONCLUSIONS <br /> A. Regulatory Considerations <br /> 3 The SJLHD has established the following regulations that apply to soils <br /> ` containing gasoline products: <br /> -= 1. For concentrations of TPH less than 100 ppm, no remedial action is <br /> generally required <br /> 2. For concentrations of TPH that exceed 100 ppm and are less than <br /> 1000 ppm, monitoring wells are generally required to determine the <br /> presence of gasoline in the ground water. -} <br /> 3. For concentrations of TPH in excess of 1000 ppm, removal of the soil <br /> is generally required. <br /> Where gasoline products are found in the ground water, the S, HD may <br /> i require that they. be reduced to the level of the reco,hnended drinking water <br /> action levels, as published by the Department of Health Services. These <br /> levels for BTX are 0.7 ppb for benzene, 100 ppb. for toluene, and 620 ppb for <br /> 3 xylene. <br /> �. <br /> B. 'Summary of Results <br /> All`soil 'samples tested for TPH were found to have concentrations below { <br /> F the detection limit (10 ppm), except at MW-1 ata depth of 5-1/2 feet, where <br /> the concentration was 1100 ppm. The laboratory tests .on ground=water samples <br /> indicated non-detectable.BTX in Mlf-2,;.MW-3, and MW-4 and xylene concentrations ; <br /> 3 <br /> of .076 ppm-in MW-1. Benzene-and teluene--were non-detectable.-in the MW-1 <br /> sample. 1'PH were detected'only in tl-ie ground-water samples fram.MW-1 at 4 ppm: <br /> EDB, a'constitutent of unleaded gasoline, was not detected in any of the water <br /> sarr,ples. .: <br /> # a <br /> �, •' ll <br />