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either well. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 µg/L. The nearby land to the north of the Site is residential, while the land to the south is industrial and agricultural, and a gravel pit is located to the southwest. It is likely that elevated nitrate levels in the area derive from fertilizer application on the agricultural properties as well as from residential septic systems. On-Site Wells One well is currently located on the Site. Four well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department: • May 1982 permit for pump installation at well. • June 1988 permit for pump replacement at well. • May 1996 permit for new domestic well; the well is located on the adjacent parcel to the south. • April 2004 permit for new well with submersible pump. The permit notes that the pump was set at a depth of 483 feet, and the standing water level was 120 feet. These permits have been included in Appendix 4 of this report. Water Sample Live Oak collected a water sample from the well on the Site on December 18, 2020. 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 3.2 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 LOGE 20-60 Page 5