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iJ j� 1 j LEVI N E•FRICKE the sampling and analysis in this location,. the area with concentrations above the TTLC appears to' be relatively localized G to an area less than approximately 20 by 20 jr The pesticide Dieldrin was detected in only one sample throughout the Site, and at a concentration well below the TTLC of 8 ppm. Dieldrin therefore does not appear to have significantly affected soil quality at the Site. 11 i 13.2 Fuel .j Total Petroleum Hydrocarbons (TPH) as di�esel�tel and toluene were detected in shallow (less than 3.5 feet below grade) soil d ground-water samples collected in the vicinity o -the a ported former underground gasoline tank lobation. The results for ground water indicated the possible presence of significant, .f. 1 elevated concentrations of TPH (2.7 ppm as diesel) in ground water at location WS-7; TPH was not detectedAiin borehole WS-_6; C--approximately 1.0 feet to the north (Figur're 6) . Because these ground-water samples were collected directlyjfrom open boreholes and not from ground-water monitoring wells, these results cannot be considered as quantitative, but may be taken as a qualitative indication of elevated concentrations of fuel in ground-water at l this locati-6n. TPH as diesel fuel was detected in a low concen- tration in one a shallow (1.5 feet below, grade) soil sample col- lected in the vicinity of the former underground tank. These l results indicate that diesel fuel was likelytstored in this tank l at one time, and that a small amount of spillage may have occurred during tank usage or removal. 1 Toluene was detected in low concentrations (well ,below the RWQCB "designated level" for toluene of 100 ppm) in the soil borings located near the underground storage tank and the two above ground tanks. Toluene was detected near' its;;Idetection limit in one ground-water sample (WS-6) collect in the vicinity of the former underground tank. Given the law concentrations of toluene, and the absence of other aromatic compounds commonly associated with fuels (i.e. benzene, ethylbenzene, and xylenes) , the occurrence of toluene may be the result of the natural degradation of organic matter in the soils at the Site. i� TPH was not detected in either the soil or ground-water samples. collected in the vicinity of the above-ground fuel tanks. These tanks therefore do not appear to have had a significant affect on soil or ground-water quality in the locations sampled. 13.3 Other 'f The results dial not indicate the presencie ofdchlorinated pesticides or herbicides in the irrigation influent or drainage effluent water from the Site. No evidence of the use of j�