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December 16,2003 <br /> Job Number: LG03-304 <br /> Page 6 <br /> 4.4 Water Sample Location <br /> A Nitrate and DBCP water sample was collected on December 8, 2003. The water samples were <br /> collected from the faucet at the domestic well head, (10898 E. Jahant Road), see Plate 1 for well <br /> location. The samples were collected by David Welch of our office. <br /> 4.5 Sample Collection, Handling, and Transportation <br /> The samples were collected in a sterile plastic container, then decanted into clean, glass vials. <br /> The samples were stored in a cool ice chest. The samples collected at 9:05 A.M., December 8, <br /> 2003 and were remanded under chain of custody to Precision Enviro-Tech, Stockton at 10:15, <br /> A.M., December 8, 2003. The Chain of Custody document has been included in the appendix of <br /> this report. <br /> 4.6 Water Sample Analytical Results <br /> Nitrate as nitrogen was found at 25.5 mg/L-NO3,which is well below the maximum contaminant <br /> level set by the United States Environmental Protection Agency of 45 mg/L-NO3. DBCP was not <br /> detected in the water sample. The analytical reports prepared by Precision Enviro-Tech can be <br /> found in the appendix of this report. <br /> The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin <br /> County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the <br /> application of fertilizers, livestock waste, and untreated septic tank waste. Nitrate is mobile and <br /> often accumulates in the shallow ground water zones. <br /> In the early 1900s, natural levels of nitrate in ground water were measured in forty-three(43) <br /> wells throughout the Sacramento Valley by Bryan(1923). It was thought that ground water at <br /> that time was close to "natural"conditions. Based on the work by Bryan, it is estimated that <br /> under"natural"conditions, ground water concentration containing nitrate is no more then about <br /> 13.5 NO3 (3 mg/L-N). Areas having 24.75 mg/L NO3 (5.5 mg/L-N) or more are those in which <br /> nitrate concentrations may be increasing (Hull, 1984). <br /> DBCP was not detected in the water sample. DBCP is a nematocide and soil fumigant for <br /> vegetables, and grapes. It is thought to cause health problems consisting of kidney damage, liver <br /> damage, and cancer. The use of DBCP was discontinued in 1979. The Environmental Protection <br /> Agency(EPA) set the maximum contaminant limit (MCL) at 0.2 parts per billion (ppb) because <br /> P OE RSO <br /> O ` <br /> 4y5OC♦ <br /> P <br /> 1.� <br />