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January 3,2006 <br /> i NOA Project Number: E05164A <br /> F4.2 Potential Ground Water Contamination Issues <br /> (� t'\Identifying potential ground-water contamination sources was not part of the scope of work for the <br /> soil suitability study. <br /> 6 Potential ground-water contamination can occur from a number of sources which often include <br /> leaky_underground storage tanks, agricultural activities, dairies, septic systems, and storm water <br /> infiltration. Any.past agricultural activities and the present use of septic systemsm the area should. <br /> rbe considered potential ground-water contamination sources. <br /> 1 <br /> 4.31 Water Sample Location <br /> No well permit was found for the subject property address of 9524 South Airport Way, during file <br /> review at EHD on December 19, 2005. <br /> i <br /> One water sample was taken on December 9, 2005 from a spigot on the south side of the market at <br /> �7outb Airport Way on Parcel number 177-080-10. The location of the sample is depicted on <br /> Pl <br /> -- nts F � Water Sample Constitue <br /> r <br /> The water sample was analyzed for nitrate and DBCP. Nitrate was found a 55.0 m /L-NO3i a— <br /> i - the maximum contaminant level (MCL) set by the US EPA of 45 mg/L-Na3. was not <br /> detected in the water sample. The analytical reports prepared by Precision Enviro-Tech can be <br /> found in the appendix of this report. <br /> The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County <br /> and drh parts b�;Central Valley. Nitrate in_grou -water occurs as a result of the application <br /> of fertiliz s,�livestoc waste, and untreated septic tank waste. Nitrate is mobile and often <br /> acctnriula es in­the sha.UwAzround water zones:----- <br /> R <br /> - In the early 1900s,natural levels of nitrate in ground water were measured in forty-three (43) wells <br /> throughout the Sacramento Valley by Bryan (1923). It was thought that ground water at that time <br /> was close to "natural" conditions. Based on the work by Bryan,it is estimated that under"natural" <br /> conditions,groundwater concentration containing nitrate is no more then about 13.5 mg/L-NO3 (3 <br /> mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L-N) or more are those in which nitrate <br /> F, concentrations may be increasing (Hull, 1984). <br /> ' F <br /> 5 <br />