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1 <br /> detection limit. Ethylbenzene and xylene were detected in <br /> samples from all borings except MW1 ranging from 0.02 to <br /> 0.55 ppm. The TPH-D concentrations, were detracted between <br /> 2-1-1--and- 16W,V& in all borings except mwl: The vertical <br /> distribution of TPH-D concentrations is presented on cross <br /> sections A-A' and B-B' (Figure 4). The laboratory test <br /> results for soil sampling conducted to date are summarized <br /> in Table 2. Laboratory data sheets, chain of custody forms <br /> and laboratory quality control data are presented in <br /> j- Appendix V. <br /> • <br /> yz 4.3 Laboratory Analysis - Groundwater <br /> The laboratory analysis of groundwater samples collected <br /> from wells MW1 and Mw2 did not record the presence of BTEX <br /> ' or TPH-D above method detection limits. WO y:;MW3 recorded <br /> i.; 3.2; ppb -dthylbenzene and-220 ppb.TPH-D Concentrations of <br /> 15 ppb toluene, 13pFb ethylbenzeno, °80 ppb:'atylene inci''320fl0 <br /> PPbTPH .--D were ' recorded `i.n' wail` 'MWt-. Concentrations of <br /> feceel coliform wera detected above the 2.2 MPN (most <br /> � £ probable number) detection limit in all wells tested. The <br /> laboratory test results for the water sampling are <br /> summarized in Table 3. Laboratory data sheets, chain of <br /> ' • custody forms and laboratory quality control data are <br /> presented in Appendix VI. <br /> 5.0 Conclusions <br /> The repair of the 4000 gallon diesel tank has eliminated the <br /> primary.source of subsurface hydrocarbon contamination. fihe' <br /> residual soil' contamination :which`'remains in'pla6e provides <br /> a source'for continuing aoritaminatiori of"groundwater. <br /> The field inspection and laboratory analysis of soils z <br /> collected from the soil borings indicate that hydrocarbon-'' fry <br /> ,a cor►tamination'to the north :east` and gest of"�th�i diesel'-tank:' PPS <br /> pit resulted from ^product leaking to the subsurkace The' <br /> concentration of total petroleum hydrocarbons sbbv6-aao pilin K <br /> in all borings except''ILMI-�indicates latera] migratioxx of P$ <br /> contaminants'has occurred 'The'higher concentrations in the <br /> t , <br /> 15` fo6t'samplesand law to non-detected levels in 'shallower / <br /> soils indicates �'soil:.contamination is `a'ssociated with <br /> 16igration along the water table `surface:` TPH-D <br /> andMW4. Thea s nce of contamination in w from borings Sis <br /> concentrations} 3n well boring` MW1 is <br /> explained ,by "its locationup groundwater an topograghic <br /> gradient from the 'tank. The low non-detectable BTEX <br /> concentrations in all the soil sampleR analyzed indicates, <br /> 1), the absence of aromatic hydrocarbons in the original <br /> diesel product and/or, 2), volatilization or natural <br /> degradation has taken place over time. <br /> 5 <br />