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August 29, 2006 NOA Project Number: E06084A 4.3 Water Sample Location No well permits were found for the subject property during file review at the EHD on July 31, 2006. F1One domestic well,however, is known to exist on site. A water sample was taken from the spigot of the domestic well on July 17, 2006 by Mr.Jessen 0 Welch. (Plate 1). 4.4 Water Sample Constituents / The water sample was analyzed for nitrate and DBCP. Nitra'E s found at 42.3 m /L-NO3,below the maximum contaminant level (MCL) set by the US EPA o 45 g/L- 3 D P was not detected in the water sample. The analytical reports prepared FGL Environmental 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 concenDpes. ' y be increasing (Hull, 1984). { DBCPtected in the water sample. DBCP is a nematocide and soil fumigant for + vegetabIt is thought to cause health problems consisting of kidney damage,liver damage, er. 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 sterile glass vials. The samples were then transported on ice and remained under chain of custody to FGL Environmental, Stockton. 4.6 Chain of Custody r The Chain of Custody document has been included in the appendix of this report. l 5 l