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L <br /> April 13, 2006 <br /> NOA Project Number: E05130B <br /> LThe presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County <br /> L and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of <br /> fertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates <br /> in the shallow ground water zones. <br /> LIn the early 1900s,natural levels of nitrate in ground water were measured in forty-three (43) wells <br /> L 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 is no more then about 13.5 mg/L-NO3 (3 <br /> L mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L-N) or more are those in which nitrate <br /> concentrations may be increasing (Hull, 1984). <br /> L DBCP ts not dete ed in the water sample. DBCP is a nematocide and soil fumigant for <br /> vegetaband gr es. It is thought to cause health problems consisting of kidney damage,liver <br /> damage,an cer. 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 /> 4.5 Well Water Sample Collection, Handling, and Transportation <br /> The nitrate sample was collected in a sterile plastic container, the DBCP sample was collected in two <br /> ` sterile glass vials. The samples were then transported on ice and remained under chain of custody to, <br /> LFGL Environmental in Stockton. <br /> L4.6 Chain of Custody <br /> LThe 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 California Geological Survey Geologic Map of Cenozoic Deposits of the San <br /> Francisco-San Jose Quadrangle (1991) as within the CDMG Map 5A. The Modesto Formation consists <br /> Lof Arkosic alluvium forming Mokelumne River terraces and alluvial fan;chiefly sand with minor <br /> 6 <br /> A44L <br /> L <br />