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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 than 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 nitrate 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 nitrate over time can also lead to gastric problems. DBCP is a nematicide 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 be required to remove this contaminant should it occur in drinking water. The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. On-Site Wells A domestic well is located on the Site. The San Joaquin County Environmental Health Department well permit files were searched for the Site addresses; two permits were identified: • December 2002 permit for new domestic well with a total depth of 183 feet and a grout seal depth of 100 feet. The permit notes that the old well was filled with bentonite (20295). • August 2008 permit for new pump at domestic well (20295). These permits have been included in Appendix 4 of this report. Water Sample Live Oak collected a water sample from the domestic well on the Site on April 9, 2026. The sample was analyzed for nitrate and dibromochloropropane (DBCP) per San Joaquin County Environmental Health Department policy. LOGE 2619 Page 4