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San Joaquin County experienced its highest recent ground-water levels in 1983 and <br /> 1999. Review of ground-water maps for spring of these years (Plates 7 and 8) reveals <br /> that depth to water would have been approximately 44 to 45 feet. <br /> Potential Ground Water Contamination Issues <br /> The Soil Suitability Study is not intended to be an investigation into ground-water <br /> contamination sources, and no such investigation was conducted. Many sources can <br /> contribute to ground water contamination, including leaking underground storage tanks, <br /> 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 /> Two common ground-water contaminants in San Joaquin County are nitrate and <br /> dibromochloropropane (DBCP). Live Oak reviewed the San Joaquin County <br /> Environmental Health Department's maps of Nitrate — Land Use Data and DBCP— Land <br /> Use Data dated February 20, 2019. According to the nitrate map (Plate 9), four wells <br /> within a half-mile radius of the subject Site have been tested for nitrate. Nitrate was <br /> detected in two of these wells at concentrations between 0.1 and 5.0 mg/L-N, and in two <br /> at concentrations above 10 mg/L-N. According to the DBCP map (Plate 10), three wells <br /> within a half-mile radius of the Site have been tested for DBCP; it was detected in one <br /> of the wells at a concentration over 0.2 ug/L; no DBCP was detected in the other two <br /> wells. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 <br /> mg/L-N; the MCL for DBCP is 0.2 ug/L. <br /> On-Site Wells <br /> Two domestic wells and an irrigation well are currently located on the Site. Two well <br /> permits were identified for the Site from among the files of the San Joaquin County <br /> Environmental Health Department: <br /> • March 2009 permit for destruction of pit well. <br /> • January 2011 permit for cross-connection repair at irrigation well. <br /> These permits have been included in Appendix 4 of this report. <br /> Water Sample <br /> Live Oak collected a water sample from the domestic well that supplies the California <br /> Islamic Center building on the Site on August 7, 2019. The sample was analyzed for <br /> nitrate and dibromochloropropane (DBCP) per San Joaquin County Environmental <br /> Health Department policy. <br /> LOGE 1939 Page 4 <br />