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'LM LEEDSH ILL•HERKENHOFF INC. <br /> An attempt to distinguish between PCE contaminated vapors coming from the <br /> groundwater, and PCE vapors originating from soil contamination by sewer joint <br /> leakage will be attempted by collecting and analyzing vapor samples at various <br /> depths. <br /> The results from this soil vapor analysis can be useful in estimating the <br /> location of PCE "hot spots, " (i .e. , sewer joints which might have leaked) and <br /> also aid in selecting the additional monitoring well locations. However, the <br /> procedure cannot be used to specify the exact location of joint leakage, or <br /> analytically quantify the level of contamination. Therefore, if the soil vapor <br /> testing indicates 'high soil contamination at particular location(s) , a soil <br /> sample(s) will be collected at or near these locations to provide quantification <br /> of the findings of the soil vapor analysis. <br /> Inspection of the City of Stockton's sanitary sewer maps indicate that the main <br /> line serving LVC heads due west, through an easement in the yards of residential <br /> homes, making access impossible. Therefore, the proposed soil vapor investiga- <br /> tion will be confined to LVC property. <br /> Soil Sampling <br /> If results from the soil vapor testing indicate "hot spots" of soil contam- <br /> ination, a soil sample(s) will be collected. The purpose of these samples will <br /> be to verify the suspected contaminant location identified by the soil vapor <br /> testing and provide analytical quantification of contaminant levels. The samples <br /> will be collected by driving a 1 -inch diameter hollow barrel , lined with 1-inch <br /> diameter brass tubes using a hand-operated driver. If samples are collected <br /> along any of the sewer laterals, the tube will be offset approximately five feet <br /> from the center line of the sewer line, and angled such that the sample will be <br /> gathered at a depth of approximately 3 feet below the invert of the line. A <br /> hydraulic lift will be used to remove the sampling tube. Immediately afterwards, <br /> the barrel will be opened and the brass tubes recovered. <br /> Once removed, all samples will be wrapped, carefully marked, and identified. <br /> The samples will then be carefully preserved for analysis in accordance with EPA <br /> and State of California protocol . Before transport to the laboratory, samples <br /> will be cooled to 4-C at the site and maintained at that temperature until they <br /> are received at the laboratory. Prior to the transport, the samples will be <br />