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F! i <br /> October 31, 2005 <br /> NOA Project Number: E05137A <br /> In the early 1900s,natural levels of nitrate in ground water were measured in forty-three (43) wells <br /> throughout the Sacramento Valley by Bryan (1923). It was thought that ground water at that time <br /> was close to "natural" conditions. Based on the work by Bryan,it is estimated that under"natural" <br /> conditions,ground water concentration containing nitrate has a concentration of no greater then <br /> about 13.5 mg/L-NO3 (3 mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L-N) or more are <br /> those in which nitrate concentrations may be increasing (Hull, 1984). <br /> DBCP was not detected in the water sample. DBCP is a nematocide and soil fumigant for <br /> vegetables and grapes. It is thought to cause health problems consisting of kidney damage, liver <br /> damage, and cancer. The use of DBCP was discontinued in 1979.The Environmental Protection <br /> Agency (EPA) set the maximum contaminant limit (MCL) at 0.2 parts per billion (ppb) because the <br /> EPA believes that given present technology and resources, this is the lowest level to which water <br /> systems can reasonably be required to remove this contaminant should it occur in drinking water. <br /> Fi4.5 Well Water Sample Collection, Handling, and Transportation <br /> The samples were collected in a sterile plastic container and two sterile glass vials. The samples were <br /> F! then transported on ice and remained under chain of custody to Precision Enviro-Tech, Stockton. <br /> 4.6 Chain of Custody <br /> FiThe Chain of Custody document has been included in the appendix of this report. <br /> 5.0 SOIL PROFILE AND GEOLOGIC INFORMATION <br /> The Site is depicted on the US GS Preliminary Geologic Map of Cenozoic Deposits of the Bellota Quadrangle as <br /> consisting of Mehrten Formation geology with small areas of Turlock Lake Formation and <br /> ` undifferentiated alluvium and colluvium (OFR-79-664). The Mehrten Formation is made up of <br /> andesitic conglomorate, sandstone, mudstone, and lahars. The Turlock Lake Formation is made up <br /> of arkosic alluvium and some locally-derived alluvium (Plate 7). <br /> The surface and near surface soils located at the Site are reported by the San Joaquin County Soil Survey <br /> to be composed of Montpellier-Cometa Complex, 5 to 8 percent slopes and Tokay fine sandy loam, <br /> 0 to two percent slopes (Plate 8) (USDA, 1992). Table 2 presents some selected properties of these <br /> soils: <br /> F <br /> Fl <br /> 5 <br /> F1, <br />