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CONCLUSIONS AND RECOMMENDATIONS <br />In summary, the soil conditions examined near the proposed septic system drain field <br />were found to be suitable for a standard septic system utilizing leach lines with seepage <br />pits. A satisfactory soil percolation rate of 4.72 min/in was observed in the shallow soil <br />zone at the test location. The soil in the test location was found to be sandy silt. <br />The depth of ground water based on recent aquifer levels is approximately 58 to 63 feet <br />below ground surface. The ground-water flow is to the northeast at a rate of <br />approximately 8 to 16 feet per mile in the vicinity of the Site. <br />A water sample was collected from the domestic well on the Site as part of this <br />investigation. Nitrate was detected in the sample at a concentration of 0.7 mg/L-N, well <br />below the MCL of 10 mg/L-N. DBCP was detected in the water sample at a <br />concentration of 0.02 !Jg/L, below the MCL of 0.2 11g/L but above the MCLG of 0 A,g/L. <br />Though water filtration will not be mandated at this level, the residents of the Site may <br />wish to consider a filtration system due to the presence of DBCP. <br />Based on the methods and assumptions described, the nitrate loading calculation <br />indicates that the use of on-site septic tanks and drain field systems on the Site has the <br />potential to cause a buildup of nitrate in the aquifer up to 8.8 mg/L, below the maximum <br />drinking water standard of 10 mg/L-N. Because of the favorable result of the nitrate <br />loading calculation, no nitrate mitigation is recommended at this time. <br />LOGE 2132 Page 13