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DBCP was detected in two wells at concentrations between 0.01 and 0.2 ug/L, and in one well at a concentration over 0.2 ug/L; no DBCP was detected in the remaining two wells. On -Site Wells Two domestic wells and two irrigation wells are located on the Site (Plate 4). Four well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department: • April 1975 permit for new domestic well at southern house. The grout seal was reportedly placed at 50 feet. • February 2012 permit for new replacement domestic well at southern house. The proposed depth was 240 feet, and the grout seal was placed at 100 feet. • July 2014 permit for pump replacement at domestic well at southern house. The standing water level was listed as 30 feet. • October 2015 permit for pump replacement at domestic well. The standing water level was listed as 30 feet. These permits have been included in Appendix 4 of this report. Water Sample Live Oak collected a water sample from the domestic well at 22844 South Frederick Avenue on the Site on August 30, 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. Nitrate was detected in the water sample at a concentration of 5.5 mg/L-N. DBCP was detected in the sample at a concentration of 0.053 µg/L. 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 LOGE 2233 Page 4