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F rovide a substrate carbon source for denitrification. The organic matter test result ot depth illustrates a concentration double the other two depths of 42 inches and As referenced above, this may be the source contributing to the high TKN n for the 2-foot East Test Pit sample. Since septic effluent is composed predominately of ammonium (NH4), the pH, along with the Cation Exchange Capacity (CEC), have significant influence on ammonium molecules. The pH of the soil profile is alkaline, which may inhibit ammonium formation and stability, and therefore nitrification. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. CEC test results of 9.5, 10.7 and 12.5 suggests there is some potential for the retention of ammonium molecules for microbial uptake, and nitrification suppression. As noted from these Leachfield test results,the nitrate-nitrogen concentration at the seven-foot depth was 22 ppm NO3-N. This correlates with the concentration as determined in the East Test Pit at the 12-ft depth of 20 ppm as NO3-N. The distance between these two samples was approximately 200 feet. This illustrates the spatial variability of NO3-N concentrations within the soil environment. C. PERCOLATION TEST RESULTS It is our understanding that percolation tests were conducted by Kleinfelder, Inc. in June of 1997 on APN 190-230-07, and on three of the surrounding parcels. Two of the parcels had failing perc rates. Two additional perc test borings were drilled and tested with passing results. Consequently, the Environmental Health Department has requested that since APN 190-230-08 is a separate parcel, a perc test must be conducted for verification of percolation in the anticipated area of the future leachfield. On February 18, one perc test boring of 42 inches and one test boring of 7 feet were prepared in the anticipated leachfield location of APN 190-230-08. The 42 inch boring represents the maximum depth of standard leachline trenches,while the 7.5 foot perc tests represents percolation that would occur in a sump. After drilling the test borings, the bottom and sides were scarified to open smeared soil surfaces. The test borings were then pre-saturated nn Fehru�ry 20 with six inches of clear water. After 24 hrs, all the water had seeped away in both borings. Percolation testing commenced on February 21, 2002 under U.S.E.P.A. and San Joaquin County Environmental Health guidelines. As illustrated on the attached FIELD PERCOLATION TESTING REPORTS, perc rates for the two test borings show favorable percolation for the 7.5 foot test boring and a mediocre perc rate for the 42 inch boring. The perc rate slowed over the 4-hr test in the deep boring, due to increased soil saturation, but remained relatively constant in the shallow test boring. In addition to the conventional perc tests described above, a hydraulic conductivity test of the shallow soil from zero to 18 inches in depth was conducted. After four hours of testing, the shallow soils absorbed 8,000 cc/hr. This is equivalent to 0.0352 gal/min or 50.7 gallons/day. 5 Chaney Cmuufting