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Water Sample Live Oak collected a water sample from the domestic well on the Site on July 8, 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 three 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. Ms. Tijero is aware that nitrate levels at the Site exceed the MCL and is utilizing a filter to remove nitrate from the domestic water. At her request, a second sample was collected from the spigot left of the garage door, which is connected to the water supply after filtration. This sample was also collected in a plastic container for nitrate analysis, placed on ice, and transported under chain of custody to FGL Environmental, Stockton. Nitrate was detected in the wellhead water sample at a concentration of 19.4 mg/L-N. DBCP was not detected in the sample. Nitrate was detected in the post -filtration water sample at a concentration of 2.9 mg/L-N. 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 ug/L) because it believes that given present technology and resources, this is the lowest level to which water systems can LOGE 2234 Page 4