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any of the wells. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 ug/L. On-Site Wells A domestic well serves the Site (Plate 3). Two well permits were identified for the Site at the San Joaquin County Environmental Health Department: • June 1972 permit for new domestic well; the well was 140 feet deep, and the grout seal was installed at a depth of 50 feet; • November 2002 permit for pump repair at domestic well. These permits are included in Appendix 4. Water Sample Live Oak collected a water sample from the domestic well on the Site on January 22, 2019. The sample was analyzed for nitrate and dibromochloropropane (DBCP) per San Joaquin County Environmental Health Department policy. As required by the laboratory, the sample was collected in a plastic container and two glass vials for nitrate and DBCP analysis, respectively. A trip blank was also utilized. The sample was placed on ice and transported under chain of custody to FGL Environmental, Stockton. Nitrate was detected in the sample at a concentration of 28.3 mg/L-N. DBCP was not detected in the water sample. Nitrate is commonly detected in shallow ground water aquifers of the Central Valley. Application of fertilizers, livestock waste, and untreated septic tank waste can all contribute to nitrate in ground water. Nitrate is mobile and tends to accumulate in shallow ground water zones. Based on work in the Sacramento Valley from the early 1900s, it is estimated that under "natural" conditions, ground water contains nitrate at concentrations no more then about 3.0 mg/L-N. Nitrate may be increasing in areas with concentrations of 5.5 mg/L-N or more (Hull, 1984). The US EPA has set the Maximum Contaminant Level (MCL) for nitrate at 10 mg/L-N. DBCP is a nematocide and soil fumigant for vegetables and grapes. It is known to cause male reproductive effects and is classified as a probable human carcinogen. Most domestic use of DBCP was discontinued in 1977 through 1979. The US EPA set the MCL at 0.2 parts per billion (ppb, equivalent to ug/L) because it 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. The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. LOGE 1843 Page 4