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Potential Ground Water Contamination Issues The Soil Suitability Study is not intended to be an investigation into ground-water contamination sources, and no such investigation was conducted. Many sources can contribute to ground water contamination, including leaking underground storage tanks, agricultural activities, dairies and cattle ranches, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area are known ground water contamination sources with the potential to impact the Site. Live Oak reviewed the San Joaquin County Environmental Health Departments Water `I J Well Data Table dated March 10, 2009 for nearby addresses that have been tested for nitrate and dibromochloropropane (DBCP). Eight wells were identified at addresses within approximately one-half mile of the subject Site. All of the wells had been tested for nitrate; it was detected in six of the wells at concentrations ranging from 0.4 to 22 mg/L. Two of the wells had been tested for DBCP; it was detected at concentrations of 0.02 and 0.34 ug/L. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 ppm. The MCL for DBCP is 0.2 ug/L. On-Site Wells One domestic well and three irrigation wells exist on the Site. No well permits were identified for the Site at the San Joaquin County Environmental Health Department. Water Sample Live Oak collected a water sample from the domestic well on June 8, 2015. 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. s� The sample was placed on ice and transported under chain of custody to FGL �) Environmental, Stockton. Nitrate alas detected at a concentration of 0.4 mg/L-NO3 in the water sample. 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 (3 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 NO3 at 45 mg/L (10 mg/L-N). LOGE 1505 Page 4