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ii <br /> 28 January 1993 <br /> (GeoAudit CV43F1-1.35) <br /> r- <br /> Page 4 of 5 ; <br /> �y <br /> f <br /> FINDINGS <br /> .i <br /> The generalized stratigraphic sequence in ;the boring consisted of <br /> alternating layers of sandy silt, silty sand and silt/clay <br /> mixtures. The depth to groundwater in the!jwell, as measured on 8 <br /> ` January 1993, was 91.90 feet. <br /> organic vapors were detected only in soil sample B3-90, at 13 parts <br /> per million (see attached boring logs) . No hydrocarbon odor was <br /> noticed in the water sample. <br /> Four soil samples from MW-2 were analyzed. No hydrocarbon <br /> contamination was detected in any -of the four soil samples. Total. <br /> lead was detected in three of the four "soili, samples at levels <br /> ranging from 5. 5 ppm to 8 . 5 ppm. Table 2 summarizes the laboratory <br /> results. The laboratory report and chain of custody for the soil <br /> samples are included in appendix A. <br /> The water sample from MW-2 was analyzed according to EPA method <br /> 8015, and total petroleum hydrocarbons in the gasoline range (TPH- <br /> �, g) were detected at a concentration of 83 ug/L (ppb) . Analysis <br /> according to method 8020 detected benzene at a concentration of 1. 0 <br /> ppb, but no toluene, ethylbenzene or xylenes were detected. <br /> f <br /> However, an unknown hydrocarbon with a boiling;` point intermediate <br /> between that of benzene and toluene was detected in the sample (see <br /> chromatogram of the 8020 analysis) . The hydrocarbon was suspected <br /> to be a halogenated solvent. Therefore, the: sample was analyzed for <br /> halogenated volatile organic compounds (HVOC's') by EPA 601. Eight <br /> of the 28 target analytes were detected injlthe ;water sample. These <br /> individual constituents included 1, 1-Dichlor8ethene (1.20 ppb) , <br /> 1, 1, 1-Trichloroethane (16 ppb) and Trichloroethene (36 ppb) . The <br /> sum of these concentrations exceeds the '83 ppb TPH-g that were <br /> { detected in method 8015, which indicates that all of the TPH-g can <br /> be accounted for by the concentrations of HVOC' s. As reported by <br /> WEST laboratories in the accompanying fetter, the TPH is not <br /> typical gasoline, and is probably the halogenated hydrocarbons. The <br /> laboratory reports and chains of custody are included in Appendix <br /> f: B. <br /> 1 <br /> '' , CONCLUSION AND RECOMMENDATIONS <br /> l <br /> 1 <br /> No contamination was detected in soil samlples collected from the <br /> monitoring well drilled during this phase13of investigation. There <br /> i is no evidence of vadose zone contamination inrthe vicinity of the <br /> } boring, indicating that MW-2 is located beyond the margin of the <br /> i <br /> soil contamination plume. <br /> I� I� <br />