Laserfiche WebLink
4 <br /> V � � <br /> December 7,2005 <br /> NOA Project Number. E05141B <br /> t 4.4 Water Sample Constituents <br /> V <br /> ter sample was analyzed for intra e and DBCP!Nitrate was found au G1.7 /L-NO3,which <br /> abov the maximum contaminant 11(MCI� s_et'by the US EPA of 45 mg/L-NO3. DBCP was <br /> n ected in the water sample. The analytical reports prepared by Precision Enviro-Tech can be <br /> found in the appendix of this report. <br /> V <br /> L The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County <br /> and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of <br /> fertilizers,livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates <br /> in the shallow ground water zones. <br /> w <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 /> i <br /> conditions,ground water 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 /> concentrations may be increasing(Hull, 1984). <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 /> damage, and cancer. The use of DBCP was discontinued in 1979.The Environmental Protection <br /> Agency (EPA) set the maximum contaminant limit(MCL) at 0.2 parts per billion (ppb) because the <br /> EPA believes that given present technology and resources, this is the lowest level to which water <br /> L systems can reasonably be required to remove this contaminant should it occur in drinking water. <br /> 4.5 Well Water Sample Collection, Handling, and Transportation <br /> The nitrate sample was collected in a sterile plastic container, the DBCP sample was collected in two <br /> Lsterile glass vials. The samples were then transported on ice and remained under chain of custody to <br /> Precision Enviro-Tech in Stockton. <br /> 6. 4.6 Chain of Custody <br /> h' The Chain of Custody document has been included in the appendix of this report <br /> L <br /> 6 <br /> V <br /> '044 L <br /> L <br />