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On -Site Wells Two domestic wells are located on the Site (Plate 2). Three well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department: • May 1980 permit for new domestic well. The grout seal was placed at a depth of 50 feet. • October 1996 permit for pump replacement at domestic well. The permit indicates that the pump was set at a depth of 140 feet, and standing water was present at 80 feet. • March 2021 permit for new domestic well. The permit indicates that the pump was set at a depth of 180 feet, and standing water was present at 100 feet. The permits have been attached in Appendix 4 of this report. Water Sample Live Oak collected a water sample from the northern domestic well on the Site on February 24, 2022. 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. Trip blanks were 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 16.3 mg/L-N. DBCP was not detected in the water sample. The laboratory analytical results are attached as Appendix 5 of this report. 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 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. Although nitrate is a naturally -occurring compound necessary for plant growth, it can cause health problems when present at high levels in drinking water. The most common health effect of nitrates in water is methemoglobinemia, or blue baby LOGE 2211 Page 4