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FFB. SOEL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS site has level terrain; consequently, there will be no need to incorporate designons for slopes. The United States Geological Survey (USGS) indicates the on-site soils to consist of a Jacktone clay (180) and a Veritas fine sandy loam (266). The leachfield for the facility is proposed to be installed in the Veritas fine sandy loam. Favorable perc rates were obtained in this soil type. An I 1 ft hand boring was completed in the location of the proposed leachfield area. The log of boring illustrates the variability of the subsurface soil characteristics encountered. The surface soils to two feet consist of a black clay soil, indicative of an organic clay. Below two feet exists a severe hardpan which extends for approximately 1.5 ft. Underlying the hardpan stratum is a sandy silt which becomes a silty sand from 5.5 ft to 6.5 ft. Silt and clay strata are found to boring termination. A feature of the soil observed in this boring was rust mottling of the silt strata. This can be attributed to seasonal soil saturation. As the water encounters a strata of slower permeability after percolating through sand of higher permeability, the percolating water "pools" on the top of the slower permeability layer. This creates an anaerobic zone. Rust mottling occurs when anaerobic bacteria decompose organic matter and create oxidized iron(rust) in their metabolic processes. Indication that these two conditions are present- organic matter and an anaerobic environment demonstrate that denitrification may be promoted. Denitrification is the conversion of nitrate to gaseous products and the primary means by which nitrate concentrations are reduced. Two soil samples were obtained from the proposed leachfield area. The first sample was retrieved from the anticipated leachline depth of 3 to 4ft. The second sample was taken from boring termination at 10 to I I ft. As the noted on the two SOIL ANALYSIS REPORTS, the nitrate-nitrogen(NO3-N) concentration at the 10-11 ft elevation is 17 ppm,while the nitrate- nitrogen concentration at the 3 to 4 ft depth is 5 ppm. This higher nitrate-nitrogen concentration at the deeper depths can be attributed to the downward migration of nitrate molecules over the years. However, the lower nitrate-nitrogen concentration at the shallow depths may be an indication of denitrification. Additional chemical analyses of soil composited from the two depths referenced above was also done to quantify several constituents. The important parameters for nitrate loading assessment are the organic matter, pH,cation exchange capacity (CEC), along with nitrate-nitrogen content. As noted,the organic matter in the soil is medium at the shallow depths and slightly lower at the deeper depths. This indicates a potential for additional nitrate-nitrogen loading in the future. Since septic effluent is composed predominately of ammonium (NH,),the pH, along with the CEC, are significant influences on ammonium molecules. The pH of the soil is alkaline which may slightly inhibit ammonium formation and stability. The CEC measures the ability of the soil to theoretically trap and hold ammonium molecules. A CEC of 14.9 and 21.0 from the respective depths indicates there is considerable potential for the retention of ammonium molecules for microbial uptake, and suppression of nitrification. 2 va!!ey Ag Research