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L May 17,2005 NOA Project Number: E04146B L Pnae5 4.4 Water Sample Constituents LThe water sample was analyzed for nitrate and DBCP. The analytical reports prepared by Precision e found in the appendix of this report Late was not detected ' e water sample. The maximum contaminant level (MCL) set by the US EP mg/L-NO3. The presence of nitrates is not uncommon in shallow ground 4 water aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in groundwater L 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. LIn 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 Lwas close to "natural' conditions. Based on the work by Bryan,it is estimated that under"natural' Lconditions,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 Lconcentrations may be increasing (Hull, 1984). D2 jCP:was not detecteaithe water sample. The Environmental Protection Agency (EPA) set the contamint (MCL) for DBCP 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. DBCP is a L 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. k"4.5 Well Water Sample Collection, Handling, and Transportation L The samples were collected in a clean plastic container, then decanted into clean,glass vials. The l samples were then transported on ice and remanded under chain of custody to Precision Enviro- L Tech,Stockton. ' 4.6 Chain of Custody LThe Chain of Custody document has been included in the appendix of this report. L '�5.0 SOIL PROFILE AND GEOLOGIC INFORMATION i The Site is depicted on the USGS Geologic Maps of the Sacramento-San Joaquin Delta, California, L Bruceville Quadrangle, as consisting of basal peaty clay and natural-levee silt (MF-140;Plate 3). L 5 L ,0*4 L