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Clayton <br /> €\4 \.ait\Tnl <br /> CU:\SUI FA1;TS <br /> 3.3 HYDROGEOLOGy <br /> - Soils underlying the site generally consist of clayey sands, sandy clays, and graven <br /> sands with gravel being more abundant near the surface. Sandy sods are fairly y <br /> Permeable and allow water and contaminants to move readily through them. <br /> Appendix D contains the complete lithologic logs recorded while drilling. <br /> Depth to groundwater ranges from approximately 8 to 10 feet in the three wells. <br /> Well elevations were surveyed to daturn sea level by Tronoif&Associates. From <br /> the well elevation data, groundwater flow direction was calculated to be N3°W, or <br /> almost directly north. The groundwater gradient is 0.3 foot elevation drop per 100 <br /> feet distance, <br /> 4.0 LABORATORY ANALYSIS <br /> 4.1 PURPOSE AND SCOPE <br /> Analyses were selected to establish a baseline environmental condition at the site, <br /> and to assess soil and groundwater for possible contamination from the former <br /> use of pesticides onsit <br /> UST, from USTs upgradient of the subject site, and from the possible previous <br /> e. The soil and groundwater samples were analyzed by the <br /> following methods: <br /> - EPA Method 5030/8015-8020, for gasoline fuel and the volatile hydrocarbons, <br /> benzene, toluene, ethylbenzene, and xylene. <br /> • EPA Method 418.1 for hydrocarbon oil and grease (waste oil) <br /> • EPA Methods 8080(soil) and 608 (water) for organochlorine <br /> pesticides/polychlorinated biphenyls (PCBs) <br /> A!1 samples were transported to Clayton's laboratory under chain-of-custody. This <br /> form, along with copies of the analytical results, are in Appendix F. <br /> 42 SOIL SAMPLE ANALYSES <br /> The results of the laboratory analyses of the soil samples are summarized in <br /> Tables 1 and 2. Table I reports only detected compounds. All other compounds <br /> for which analyses were conducted were below-analytical detection limits, as <br /> shown in the laboratory report (Appendix F). <br /> TWe compared soil sample results for hydrocarbon nil and grease to concentrations <br /> the RWQCB's Recommendations for the 1?valuation and Investi anon of USTs. <br /> These concentration levels are listed in Table 2. <br /> -3 <br />