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I. INTRODUCTION Mr. Charles Harris is proposing to create eight, 2-acre residential lots in a rural, unsewered portion of San Joaquin County. The City of Ripon and the City of Manteca water and sewer systems do not extend to this project and probably never will. This report presents the results and findings of the Nitrate Loading Study and Soil Suitability Study conducted for the creation of these eight lots. Parcel creation will be accomplished by Lot Line Adjustments. The project has no officially recognized name, but will be referenced as Leroy Road-Potter Tract for this Study. It is located north of the town of Ripon on North Ripon Road, one-half mile south of Highway 120. The project is referenced in the United States Public Land Survey System as Section 5 & 6, Township 2 South, Range 8 East, M.D.B.&M.. It is bounded to the north by State Highway 120, to the south by Donahue Road, to the east by North Ripon Road, and to the west i by the eastern property line. The San Joaquin County Environmental Health Department(PHS-EHD) requires Nitrate Loading and Soil Suitability Studies for projects in unsewered areas, or for projects which may potentially impact the underlying groundwater with nitrate. This report complies with the San Joaquin County Development Title, Section 9-1105.2 for a Nitrate Loading Study and Soil Suitability Study. Additionally, this proposed project must comply with the Environmental Health Department Sewage Standards, specifically Section 10 - "Requirements for Waste Disposal for New Land Developments." Our Study documents that the aquifers under the subject property have been impacted with elevated levels of nitrate,predictably from agricultural inputs, and to a lesser extent, on-site septic systems and background levels. Consequently,the PHS-EHD has stipulated that the purpose of this Study be to 1.) investigate and quantify present nitrate concentrations, 2.) estimate potential future nitrate impact with conventional septic systems in comparison with leaving the subject property in agricultural production, and 3.) discuss mitigation measures. The estimated future impact is based on contemporary scientific knowledge used to assess factors which are extremely variable and complex within the soil and groundwater environments. The primary concern of nitrate in drinking water is that high concentrations can cause methemoglobinemia in infants and it can also induce abortion or death in cattle. This disease occurs through a series of complex chemical reactions within the hemoglobin in the blood. Only infants and young children are susceptible. Although this disease is extremely rare, nitrate can also potentially cause other health concerns. There have been scientific studies to suggest that nitrate may produce carcinogenic effects in humans. Nitrate concentrations in water can be expressed in two different terms: 1.) as the weight of the ` nitrate molecule, which is one atom of nitrogen and three atoms of oxygen for an atomic weight of 62 units. Or,2.)nitrate can be expressed as the amount of the nitrogen atom itself. This one atom of nitrogen(N) in a nitrate molecule contributes 14 atomic weight units to the weight of the nitrate molecule. The ratio of weight of the nitrate molecule (NO3)to the atom(N) is 62/14 or approximately 4.5. The U.S.E.P.A. has established the Maximum Contaminant Level(MCL)of nitrate in drinking water at 45 mg/l as nitrate. Due to the ratio described above,the MCL is ` sometimes reported as 10 mg/1 as nitrate-nitrogen. .. 1 Vafley Ag Research