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- p i PRE-TANK REPLACEMENT VTE ASSESSMENT RESULTS REPORT { - iW5 S.EI Dorado.Stockton.CNticrrM 1.4 - Pape 5 Detection limits were as follows: a) for TPPH, as gasoline, the detection limit is 0.1 mg/kg (ppm) ; t" �., b) for BTX&E the detection limits are 0.001 mg/kg (ppm) ; C) for EDC and EAB the detection limits are 0.001 mg/kg (Ppm) ; and L.4 d) for total lead the detection limit is 2. mg/kg (ppm) . In addition, a spike peak, surrogate sample and standards were run to ensure quality assurance/quality control (QA/QC) analyses per Aegis' SOP, Appendix C. Detectable concentrations of total purgeable petroleum hydrocarbons were found in some of the samples retrieved from beneath the UST basin. A single, high concentration of 16,000 mg/kg (ppm) was observed in SB-1 approximately 35 feet below grade. This sampling location was approximately .beneath the central tank in the UST basin. A duplicate analysis of this sample indicated a concentration of 14,000 mg/kg (ppm). The remainder .of the TPPH concentrations ranged from 0.19 to 0.8 mg/kg (Ppm) , and were observed in samples collected from depths ranging from approximately 18 to 30 vertical feet below grade, Relatively low concentrations of benzene, toluene, xylenes and/or 1,2- dichlaroethane were observed in all of the samples analyzed. r% Ethylene dibromide was not detected in any of the samples analyzed. The results of the laboratory analyses are summarized in Table 2. 3.4 (around linter Conditions A saturated water horizon was encountered at depths 49 and 4$§ vertical feet below grade in borings SB-1 and SB-2, respectively. Based on field observations and the soil types encountered, the -- ground water is inferred to be under unconfined conditions. Assessment of ground water quality is beyond the scope of this ` phase of investigation. r .