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w GEOTECHNICAL �I NEIL O. ANDERSON ENVIRONMENTAL ,.4 A N D A S S O C I A T E S INSPECTIONS a TESTING LABORATORY SERVICES POOL ENGINEERING POST TENSION DESIGN July 8, 2009 Our Project Number: LGS090504 Lisa Medina San Joaquin County EHD 600 East Main Street Stockton, California 95202 Subject: Soil Suitability/Nitrate Loading Study Addendum Watts Winery, APN: 051-120-36 &62 17010 North Locust Tree Road Lodi, California Dear Ms. Medina Our firm recently sent over a report for the subject property which stated that no DBCP had tested positive in the well water sample tested, as required by the San Joaquin county EHD. This letter addendum was written to address this error. DBCP was detected at 0.39 ppb. The following information should address this issue properly. Water Sample Constituents The water sample was analyzed for nitrate and DBCP. Nitrate was found at 13.3 mg/L-NO3 which is below the maximum contaminant level (MCL) set by the US EPA of 45 mg/L-NO3. DBCP was detected in the well water sample at 0.39 Ing/L. The MCL set by the US EPA for DBCP is 0.2 ug/L. The analytical reports prepared by EGL Environmental can be found in the appendix of the original report submitted to the San Joaquin EHD previously. The presence of nitrates is not uncommon in shallow ground water aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in ground water occurs as a result of the application of fertilizers, livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow ground water zones. 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, ground water concentration containing 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).