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agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural <br /> activities and the use of septic systems in the area are known ground water <br /> contamination sources with the potential to impact the Site. <br /> On-Site Wells <br /> One domestic well and one irrigation well are located on Parcel -10 of the Site. An <br /> additional irrigation well is located an Parcel -01 of the Site. Three well permits were <br /> identified at the San Joaquin County Environmental Health Department: <br /> • December 1990 permit for replacement of irrigation well, including destruction of <br /> old well (Parcel -10). <br /> • April 1991 permit for installation of new turbine pump at irrigation well (Parcel <br /> -10). <br /> • March 1993 permit for installation of new irrigation well (Parcel -01). <br /> These permits have been included in Appendix 4. <br /> Water Sample <br /> Live Oak collected one water sample from the domestic well on the Site (Parcel -10) on <br /> June 13, 2011. The sample was to be analyzed for nitrate and dibromochloropropane <br /> (DBCP) per San Joaquin County Environmental Health Department policy. <br /> As required by the laboratory, the sample was collected in a plastic container and two <br /> glass vials for nitrate and DBCP analysis, respectively. A trip blank was also utilized. <br /> The sample was placed on ice and transported under chain of custody to FGL <br /> Environmental, Stockton. <br /> Nitrate was detected in the sample at a concentration of 22.3 mg/L-NO3. This is well <br /> below-ffi6­0'S �P%,'s Maximum Contaminant Level (MCL) for nitrate of 45 mglL-NO3. <br /> DBCP was not detected in the sample. <br /> The irrigation well on Parcel -01 of the Site was not tested because its power supply <br /> was off at the time of testing. Mr. Navarra provided the results of a recent sampling <br /> event from October of 2010; during this event, nitrate was detected in the sample at a <br /> concentration of 0.31 meglL (19.2 mg/L). The test results are included in Appendix 5. <br /> Nitrate is commonly detected in shallow ground water aquifers of the Central Valley. <br /> Application of fertilizers, livestock waste, and untreated septic tank waste can all <br /> contribute to nitrate in ground water. Nitrate is mobile and tends to accumulate in <br /> shallow ground water zones. Based on work in the Sacramento Valley from the early <br /> 1900s, it is estimated that under "natural" conditions, ground water contains nitrate at <br /> concentrations no more then about 13.5 mg/L-NO3 (3 mg/L--N). Nitrate may be <br /> LOGE 1118 Page 4 <br />