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FF 3. SSS§ 2 ,4.2. Since surrounding properties have been intensely fanned for e th ote for nitrate contamination in the underlying groundwater is. However, groundwater research in the scientific literature suggests there may be a rification potential within aquifers or saturated zones composed of a fine clay soil A second critical issue regarding the groundwater elevation in combination with the five-foot separation distance, is that the water table cannot encroach up to the septic tanks, which may cause i buoyancy. This is discussed in the "Conclusions and Recommendations" Section of this Report. NLS§ 3,S 2. S§4. ,4.4, .5. As referenced, there was no electricity to the referenced well, and therefore,could n be d. However, a sample was taken from the City of Tracy water. This sample was obtained from a hose bibb near the aforementioned well. The water was allowed to i run for 30 minutes to ensure that water from the main in Larch Road was being sampled, and not stagnant water that may have existed within the piping leading to this hose bibb. A one-half liter plastic bottle was used for the water sample. The sample container was placed in a cooled ice chest and then transported to A& L Western Agricultural Labs in Modesto, under the attached Chain of Custody. The constituents tested were for nitrate, total alkalinity and chloride. Medium-to-high groundwater chloride concentrations may indicate contamination from septic system effluent, since human wastes are generally high in chloride content. Chlorides travel exceptionally well in the soil environment, even better than nitrate, and can be an excellent indicator of septic effluent pollution. The City of Tracy water reveals low concentrations of all the constituents tested, as illustrated in the following Table: TABLE 4 CITY OF TRACY WATER ANALYSIS ANALYTE LEVE FOUND MAXIMUM CONJAMINANT LEVEL (MCL) Nitrate 6 45g/L(Ppm) Total Alkalinity 109�ng/L o Standard Chloride 74 500 mg/L Calculation of Alkalinity Requirement for Nitrification The nitrate-nitrogen loading estimation on Page 14 is contingent upon the environmental factors required for nitrification to occur. These conditions include soil pore-space oxygen content, soil temperature,pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the City of Tracy water supply in addition to the introduction of wastes. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen(NH4-N) oxidized. Nitrification of the average Total Nitrogen(TN) concentration of 113 mg/L, as determined on Page 13 would require: 113 mg/L NH4-N x 7.1 mg CaCO3 = 802 mg/L alkalinity. The alkalinity in the domestic water supply is presently 109 ppm, which may theoretically retard nitrification to an indeterminable degree. 7 Chesney Consulting