SU0005909 SSNL - Laserfiche WebLink

Home Browse Search

July 19, 2006 NOA Project Number:E05165B Page 2 In the early 1900s, natural levels of nitrate in ground water were measured in forty-three (43) wells throughout the Sacramento Valley by Bryan (1923). It was thought that ground water at that time was close to "natural' conditions. Based on the work by Bryan,it is estimated that under"natural' conditions,the ground water concentration of nitrate is no more then about 13.5 mg/L-NO3 (3 mg/L-N). Areas having 24.75 mg/L-NO3 (5.5 mg/L-N) or more are those in which nitrate concentrations may be increasing(Hull, 1984). DBCP was not detected in the water sample. DBCP is a nematocide and soil finnigant for vegetables and grapes. It is thought to cause health problems consisting of kidney damage,liver damage, and cancer. The use of DBCP was discontinued in 1979. The Environmental Protection Agency (EPA) set the maximum contaminant limit (MCL) at 0.2 parts per billion (ppb) because the EPA believes that given present technology and resources,this is the lowest level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water. Conclusion In summary,DBCP was non-detectable in the well,and the nitrate concentration in ground water was found to be 46.1.0 mg/L-NO3 which exceeds the maximum contaminant drinking water limit of 45 mg/L-NO3. We recommend not drinking the well water until the well is repaired or replaced and water quality is within drinking water standards.You should contact the EHD for more details regarding health issues and repair/replacement options. Limitations The conclusions of this report are based on the information provided regarding the existing and proposed development, the use of the subject property, and the site conditions as they existed at the time we excavated our test holes and performed the percolation tests. It was assumed that the test holes and percolation test results are representative of the subsurface conditions in the general area. Our professional services were performed, our findings obtained,and our conclusions proposed in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties either expressed or implied. Test findings and statements of professional opinion do not constitute a guarantee or warranty, expressed or implied. NEIL O.ANDERSON&ASSOC.,INC. r6tloo I k an Rosulek,I.A. Davi Welch,PrinCipal Geolo Staff Scientist CEG-2151,CHG-653,PGP-1049 cc: Ron McManis, 18700 East River Road,Ripon,CA 95366