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s number) detection limit in all wells tested. The laboratory - test results for this sampling are summarized in Table 2, Laboratory data sheets, chain of custody forms and laboratory quality control data are presented in Appendix VI. 5.0 Conclusions The removal of the 5000 gallon diesel tank and associated product lines has eliminated the primary source of subsurface hydrocarbon contamination. The residual soil contamination which remains in pler_a (SBI) provides a scarce for continuing contamination of groundwater The field inspection and laboratory analysis of soils collected from the borings indicate that hydrocarbon contamination to the north of the former tank pit resulted from diesel product leaking to the subsurface. The 378 ppm concentration of total petroleum hydrocarbons in soil boring SBI at 10 feet and the absence of contamination in well boring MW4 located adjacent to the pump side of the former tank suggests leakage occurred on the north end of the tank. The presence of contamination in Sal, located 25 feet north of the pit indicates migration of diesel contamination has occurred. Based on the period of time since source removal (about two years) and the distance of contaminant migration (25 feet to Sal) the approximate rate of movement is 0.03 am feet per day. Given the site gradient, this is a typical rate for clayey silt type soils as encountered in the saturated zone at the site. The non-detectable levels of; diesel hydrocarbons in soil samples collected from MW2; MW3. and MW4 suggest the lateral extent of soil contamination has ., been defined by these borings. The non-detectable BTEX concentrations in all the soil samples analyzed (including sample Sal at 10 feet) indicates, 1), the absence of more �. volatile hydrocarbons in the original diesel product and/or 2), volatilization or natural degradation has taken place over time. The non-detectable concentrations of BTEX and TPH-D in the four groundater monitoring wells sampled indicates extensive groundwater contamination does not exist as previously w. indicated by the groundwater sample taken during tank removal. The presence of soil contamination in SBI which likely resulted from migration within the saturated zone implies dissolved hydrocarbon contamination exists in the area bounded by wells MW2, MW3, and MW4. The wells M42 and MW3 define the extent of suspected groundwater contamination in the down groundwater gradient direction. The non- detectable levels of BTEX and the 18 ppb concentration of toluene in the crigiaal tank pit water sample indicates - -- either the had ow concentrat ons o BTEX or the product leakage occurred over a period of time before the tank pull and degradation of the more volatile >4 S