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September 9,2005 NOA Project Number: E0501 1B 4.4 Water Sample Constituents The water sample was analyzed for nitrate and DBCP. Nitrate was fo at 65.1 mg/L 03,which is above the maximum contaminant level (MCL) set by the US EPA o L- 3 DBCP was not detected in the water sample. The analytical reports prepared by Precision Enviro-Tech can be found in the appendix of this report. 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 in 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 mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L-N) or more are those in which nitrate concentrations may be increasing (Hull, 1984). DBCP 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. 4.5 Well Water Sample Collection, Handling, and Transportation The nitrate sample was collected in a sterile plastic container, the DBCP sample was collected in two ! s` sterile glass vials. The samples were then transported on ice and remained under chain of custody to ( l Precision Enviro-Tech 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 California Geological Survey Geologic Maki of Cenozoic Dep osits of the San Francisco-San Jose Quadrangle(1991) as within the CDMG Map 5A. The Modesto Formation consists of Arkosic alluvium forming Mokelumne River terraces and alluvial fan; chiefly sand with minor gravel and silt;probably glacial outwash (Plate 7). 5 ..44