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I L June 6,2006 NOA Project Number: E06019B I 4.3 Water Sample Location LAccording to the tentative parcel map provided by Baumbach and Piazza, Civil Engineers, one domestic and one agricultural well exist on the site. One well permit was found during file review at L EHD on March 8, 2006. A water sample was taken from the well head of the domestic well to the Limmediate south of the residence by Ms. Nancy Rosulek on March 20, 2006 (Site Map,Plate 1). 4.4 Water Sample Constituents LThe water sample was analyzed for nitrate and DBCP. DBCP was not detected in the water sample. Nitrate was found at 4.6 mg/L-NO3i well below the maximum contaminant level (MCL) of 45 / L mg/L-NO3 set by the United States EPA.The analytical reports prepared by FGL Environmental f �� can be found in the appendix of this report LWell construction,seals, age and depth of the well screens may play significant part in assessing the levels of Nitrate and DBCP in various aquifers.Without knowing specific details regarding well construction and condition,it would be difficult to accurately comment on the condition of the aquifer. Essentially, the water sample concentration approximately indicates the contaminant concentration level of the aquifer from which the well is drawing. It is Neil O.Anderson and Associate's opinion that,in general,near surface aquifers are more likely to have elevated L concentrations of Nitrate and DBCP than the deeper aquifers. However the contaminant concentration of one aquifer cannot give any indication as to the concentrations of any other aquifer i regardless of proximity. LThe 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 Lfertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow ground water zones. L 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" L conditions,the ground water concentration of 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). L 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 Lsystems can reasonably be required to remove this contaminant should it occur in drinking water. 5 L .*44 L