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February 27,2002 <br /> Job Number:LG02-048 <br /> Page 5 <br /> with a sampler tool on February 1, 2002. The sample was sent to Precision Environmental <br /> Laboratory for testing on the same day. The samples were tested for the presence of <br /> dibromochloropropane(DBCP) and Nitrate (NO3) per County requirements. <br /> The test results indicated that DBCP was non-detectable (ND) and nitrate as nitrogen <br /> f (N)was found at 13092 ug/1 ( 13.092_jpg�l-N�. The result of the nitrate test indicates the ground <br /> water is above the maximum contaminate level set by the United States Environmental <br /> Protection Agency of 10,000 ug/L-N for nitrate(or 10 mg/L as Nitrate N or 45 mg/L as NO3). <br /> The presence of nitrates and DBCP are not uncommon in shallow ground-water aquifers <br /> in San Joaquin County and other parts of the Central Valley. Nitrate in ground water occurs as a <br /> result of the application of fertilizers, livestock waste, and untreated septic tank waste. Nitrate is <br /> mobile and often accumulates in the shallow ground-water zones. <br /> In the early 1900's, natural levels of nitrate in ground water were measured in forty-three <br /> (43) wells throughout the Sacramento Valley by Bryan.' It was thought that ground water at that <br /> time was close to"natural" conditions. Based on the work by Bryan, it is estimated that under <br /> "natural"conditions, ground water concentration containing nitrate is no more then about 13.5 <br /> NO3 (3 mg/L-N). Areas having 24.75 mg/L NO3 (5.5 mg/L-N) or more are those in which nitrate <br /> concentrations may be increasing.3 <br /> DBCP was not detected in the water sample. DBCP is a nematocide and soil fumigant <br /> for vegetables, and grapes. It is thought to cause health problems consisting of kidney damage, <br /> liver damage, and cancer. The use of DBCP was discontinued in 1979. The Environmental <br /> Protection Agency(EPA) set the maximum contaminate limit (MCL) at 0.2 parts per billion <br /> (ppb) because the EPA believes that given present technology and resources, this is the lowest <br /> level to which water systems can reasonably be required to remove this contaminate should it <br /> occur in drinking water.' <br /> ' Bryan,K., 1923,Geology and ground-water resources of Sacramento Valley of California:U.S. <br /> Geological Survey Water-Supply Paper 495,285p. <br /> 3 Hull,L.C., 1984,Geochemistry of Ground Water in the Sacramento Valley,California:U.S.Geological <br /> Survey Professional Paper 1401-B. <br /> ' EPA, 1999,Drinking water and health,National Primary Drinking Water Regulations,consumer fact <br /> sheet on:DIBROMOCHLOROPRPOANE. Internet:http://www.epa.gov./OGWDW/dwh/c-soc/dibromoc.html <br /> �pE 4S0 <br /> r t <br /> > n <br /> Z r <br /> O � <br /> `�' 1SS OL♦ <br />