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LOGE 2211 Page 3 Given that the ground elevation of the Site is approximately 38 feet above mean sea level, the depth to water below the Site is estimated to be approximately 76 to 83 feet. 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, 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. Two common ground-water contaminants in San Joaquin County are nitrate and dibromochloropropane (DBCP). Live Oak reviewed the San Joaquin County Environmental Health Department’s maps of Nitrate – Land Use Data and DBCP – Land Use Data dated February 20, 2019 (Plates 6 and 7). According to the nitrate map, six wells within a one-mile radius of the subject Site have been tested for nitrate. Three of these wells were found to contain nitrate at concentrations between 0.1 and 5.0 mg/L; nitrate was detected at a concentration between 5.1 and 10 mg/L-N in the remaining three wells. According to the DBCP map, only three wells within a one-mile radius of the Site have been tested for DBCP. DBCP was detected in two of the wells at concentrations between 0.01 and 0.2 µg/L; no DBCP was detected in the third well. 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 concentrations of 5.5 mg/L-N or more (Hull, 1984). The US EPA has set the Maximum Contaminant Level (MCL) for nitrate at 10 mg/L-N. Although nitrate is a naturally-occurring compound necessary for plant growth, it can cause health problems when present at high levels in drinking water. The most common health effect of nitrates in water is methemoglobinemia, or blue baby syndrome, which results in reduced oxygen supply to vital tissues. Pregnant women and certain others can also develop methemoglobinemia. Symptoms include a bluish color of the skin, as well as headache, dizziness, weakness, and difficulty breathing. Ingestion of high levels of nitrates over time can also lead to gastric problems. DBCP is a nematocide and soil fumigant for vegetables and grapes. It is known to cause male reproductive effects and is classified as a probable human carcinogen. Most domestic use of DBCP was discontinued in 1977 through 1979. The US EPA set