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• On-Site Wells Two irrigation wells and two domestic wells are located on the Site. Eight well permits were identified for the Site at the San Joaquin County Environmental Health Department: • September 1980 permit for new domestic well (11418). The permit depicts two old wells just to the south, one "filled with dirt" and the other "has seal." • April 1991 permit for repair to irrigation well (11418). • July 1993 permit for destruction of old well (11418). • January 2004 permit for pump repair to irrigation well (11418). The permit indicates that "well repairs not completed; cross connection without backflow prevention was noted." • November 2005 permit for new domestic well (6655). • November 2007 permit for new pump at domestic well (6655). • August 2012 permit for pump replacement at domestic well (11418). • April 2014 permit for pump repair at irrigation well (11418). The well permits have been included in Appendix 4 of this report. Water Sample • Live Oak collected a water sample from the northern domestic well on the Site on November 16, 2018. 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 9.0 mg/L-N. DBCP was not detected in the 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 13.5 mg/L-NO3 (equivalent to 3.0 mg/L-N). Nitrate may be increasing in areas with concentrations of 24.75 mg/L-NO3 (5.5 mg/L-N) or more (Hull, 1984). The US EPA has set the Maximum Contaminant Level (MCL) for nitrate as N at 45 mg/L-NO3 (10 mg/L-N). • LOGE 1845 Page 4