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L L November 21,2006 NOA Project Number: E06045B The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of fertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates Lin the shallow ground water zones. In the early 1900s,natural levels of nitrate in ground water were measured in forty-three (43) wells throughout the Sacramento Valley by Bryan (1923). It was thought that ground water at that time was close to"natural" conditions. Based on the work by Bryan,it is estimated that under"natural" conditions,ground water concentration containing nitrate is no more then about 13.5 mg/L-NO3 (3 Lmg/L-N). Areas having 24.75 mg/1,NO3 (5.5 mg/L-N) or more are those in which nitrate concentrations may be increasing (Hull, 1984). LDBCP was not detected in the water sample. DBCP is a nematocide and soil fumigant for vegetables and grapes. It is thought to cause health problems consisting of kidney damage,liver damage, and cancer. The use of DBCP was discontinued in 1979. The Environmental Protection ` Agency (EPA) set the maximum contaminant limit (MCL) at 0.2 parts per billion (ppb) because the � ` EPA believes that given present technology and resources, this is the lowest level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water. L4.5 Well Water Sample Collection, Handling, and Transportation l The nitrate sample was collected in a sterile plastic container, the DBCP sample was collected Ktwgl l" sterile glass vials. The samples were then transported on ice and r ed under chain of custo o FGL Environmental in Stockton. 4.6 Chain of Custody The Chain of Custody document has been included in the appendix of this report. 5.0 SOIL PROFILE AND GEOLOGIC INFORMATION The Site is depicted on the USGS Preliminary Geologic Map of San Francisco - San Jose quadrangle as within the Quaternary Riverbank Formation. Quaternary Riverbank Formation. w&thered reddish gravel, sand, and silt forming clearly recognizable alluvial terraces and fans late 7), / The surface and near surface soils located at the Site are reported by the San Joaquin Coun Soil Su to be composed of,Chuloak coarse sandy loam and Madera sandy loam,both 0-2% slo s (Plate 8) L (USDA, 1992). Table 2 presents some selected properties of these soils: L L5 L