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aw June 14, 2005 NOA Project Number: E05066A P/4.2 Potential Ground Water Contamination Issues Identifying potential ground-water contamination sources was not part of the scope of work for the soil suitability study. Potential ground-water contamination can occur from a number of sources ` which often include leaky underground storage tanks, agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area should be considered potential ground-water contamination sources. //4.3 Water Sample Location ` One well exists on the site.According to Mr. Garcia this well is to be abandoned. No well permits were found during file review at EHD on May 17,2005.A water sample was taken from the well head of the domestic well by Mr. Conor McGee of our office on May 25,2005;see location on to 4.4 Water Sample Constituents The water sample was analyzed for nitrate and DBCP. Nitrate was found at - the maximum contaminant level (MCL) set by the US EPA of 45-mg/1—NO, BC'P was not detected in the water sample. The analytical reports prepared by Precision Enviro-Tech can be found in the appendix of this report. Well construction, seals, age and depth of the well screens may play significant part in assessing the levels of Nitrate and DBCP in various aquifers. Without knowing specific details regarding well construction and condition,it would be difficult to accurately comment of the condition of the aquifer. Essentially, the water sample concentration approximately indicates the contaminant concentration level of the aquifer from which the well is drawing. It is Neil O. Anderson and Associate's opinion that,in general,near surface aquifers are more likely to have elevated concentrations of Nitrate and DBCP than the deeper aquifers. However the contaminant concentration of one aquifer cannot give any indication as to the concentrations of any other aquifer regardless of proximity. The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of fertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow ground water zones. 5