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January 16,2004 Job Number:LG03-304 Page 7 -4.5 Sample Collection, Handling, and Transportation The samples were collected in a sterile plastic container, then decanted into clean, glass vials. The samples were then immediately remanded under chain of custody to Precision Enviro-Tech„ Stockton on December.2.9, 2003..The water samples were placed in a cool container for transportation to the laboratory. The Chain of Custody document and laboratory results have r been included in the appendix of this report. 4.6 Water Sample Analytical Results Nitrateas ntigen^was,found to be 26.1 inj,-NN ell below-the maximum:contaminant level set by the United States Environmental Protection Agency of 45 mg/L-NO3. I]BCP was not detected in the water sample.- The analytical reports prepared by Precision Enviro-Tech can be -found in the appendix of this report..'. Thepresence of nitrates is not uncommon in shallow groundwater 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 NO3 (3 mg/L-N). Areas having 24.75 mg/L NO3 (5.5 ring/L-N) or more are those in which nitrate concentrations may be increasing(Hull, 1984). - DBCP was not de;ape�s. "�" ectd ih ' r mple. DBCP is a nematocide and soil fumigant for vegetables, an 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.- .