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July 29,2003 <br /> Job;Number: L603-222 <br /> Page 4 <br /> Table 2. <br /> Summary of Available Ground Water Information. <br /> Date,Source Groundwater Depth Notes <br /> Four borings: 3, 3-foot percolation test <br /> borings.and one and 14 fobt deep soil No ground water <br /> boring. Neil O. Anderson& encountered <br /> Associates, Inc. July 7, 2003. <br /> Water sample obtained on July$,_2003 Water tested for Nitrate,DBCP,.and EDB. <br /> from the onsite well located at 627 W. 'Nitrate: 9 mg/L-N0,,MCL 45 mg/L-NO,. <br /> Vernalis-Rd.,Tracy, CA. DBCP: not detected. <br /> Three water,samples were collected from the well head of the on-site water well on July 8. 2003 t <br /> by Ahgel Chavez of our office. The samples were collected in a plastic bailer, then decanted into <br /> a clean, glass vials. <br /> The samples were kept under r <br /> p p efngeratton until they were remanded under chaan.of custody to , <br /> Precision Enviro-Tech, Stockton, on July 11;2003. They were tested for nitrate and DBCP. <br /> Nitrate as nitrogen was�found at�9 m -N0 well•, g g/L 3, we . below the maximum contaminant level set by <br /> the United States Environmental Protection Agency of 4.5 mg/L-NO3. DBCP was not detected in <br /> the water.sample. The analytical reports, prepared by Precision Envro-Tech can be found in the <br /> appendix of this report. <br /> The presence of.nitrates is not uncommon in shallow groundwater aquifers in San Joaquin <br /> County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the <br /> application of fertilizers, livestock waste,and untreated septic tank waste. Nitrate is mobile and <br /> often accumulates in the shallow ground water zones. <br /> In-the early 1900s, natural levels of nitrate in ground water were measured in forty-three(43) ' <br /> wells throughout the Sacramento.Valley by Bryan (1923). It was thought that ground water at <br /> that time was close to "natural' conditions. Based on the work by Bryan, it is estimated that <br /> under"natural".conditions, ground water concentration containing nitrate is no more then about <br /> 13.5 NO3 (3 mg/L-N). Areas having 24.75 mg/L NO, (5.5 mg/L-N) or more are those in which I' <br /> nitrate concentrations may be increasing (Hull, 1984). F <br /> DBCP was not detected in the water sample. DBCP,is a nematocide and'soil fumigant for : <br /> vegetables, and grapes.' It is'thought to cause health problems consisting of kidney damage, liver <br />