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On-Site Wells A domestic well is located on the Site (Plate 2). Live Oak reviewed the files of the San Joaquin County Environmental Health Department for the Site address; one well permit was identified. The permit, dated September 1998, was for a new domestic well. First water was recorded at a depth of 100 feet, the pump was placed at 140 feet, and the grout seal was placed at 100 feet. Water Sample Live Oak collected a water sample from the domestic well on the Site on March 1, 2023. 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 three glass vials for nitrate and DBCP analysis, respectively. The sample was placed on ice and transported under chain of custody to FGL Environmental, Stockton. Nitrate was detected in the water sample at a concentration of 3.6 mg/L-N. DBCP was not detected in the 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 syndrome, which results in reduced oxygen supply to vital tissues. Pregnant women and certain others can also develop methemoglobinemia. Symptoms include a bluish color of the skin, as well as headache, dizziness, weakness, and difficulty breathing. Ingestion of high levels of nitrates over time can also lead to gastric problems. 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 µg/L) because it believes that given present technology and resources, this is the lowest level to which water systems can reasonably LOGE 2312 Page 4