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Project No 014-95262 Page No 15 8.7 - w The laterally extensive but very low concentrations of VOCs (benzene, toluene, bromoform, and 1,2,4-trunethylbenzene) detected in six of eight groundwater samples analyzed suggests a regional or background source for these constituents t In the one sample analyzed for semi-volatile compounds, bis(2-ethylhexyl)phthalate was detected at a concentration of 150µg/L Phthalate-containing compounds are common as nuisance constituents :n chemical analyses due to their ubiquitous presence in plastics, and have a possible source in sampling equipment, containers, analytical laboratory, etc This constituent may also be a result of regional groundwater degradation 9.0 SUMMARY OF FINDINGS Following is a summary of the pertinent findings of this investigation 1 Minor concentrations of TPH-D were noted in the northern portion of the former diesel supply/return hues The lateral and vertical extent is not defined 2 A soil sample from a below grade concrete vault adjacent to the brine tank contained 12,000 mg/kg chloride A determination of the existence of a bottom to this vault should be made If not present, the vertical definition of elevated chloride in soil at this location should be conducted The vault construction should ' be modified in either case 3 Surface observations and subsurface soil and groundwater data suggest brine spillage at the brine tank has occurred Brine has affected both soil and groundwater of sampling location KB-1 and KHP-1 The full extent of soil or groundwater impacts by chloride are not known 4 Low concentrations of VOCs and moderate concentrations of diesel in groundwater at varied locations not associated with known point sources suggests regional contamination of the shallow aquifer by these constituents KRAZAN& ASSOCIATES, INC Offices Serving the Western United States 952&2 vs2