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CONCLUSIONS AND RECOMMENDATIONS In summary, the soil conditions examined near the existing septic system drain field were found to be suitable. A satisfactory soil percolation rate of 2.98 min/in was observed in the shallow soil zone at the test location. The depth of ground water based on recent aquifer levels is approximately 45 to 68 feet below ground surface. The ground-water flow direction and gradient could not be calculated. The highest recent ground-water levels for the area were experienced in 1983, when ground water would have been present beneath the Suite at approximately 30 feet below ground surface. Because the percolation rate encountered falls between 1.0 and 5.0 min/in, the San Joaquin County Environmental Health Department will require a 20-foot separation from the bottom of the dispersal system to ground water. If the 1983 high ground-water level is to be considered, sumps no deeper than 10 feet should be utilized rather than 25-foot deep seepage pits; this option should be discussed with the San Joaquin County Environmental Health Department. The existing on-site septic system utilizes eight- foot-deep sumps, and it is anticipated that the new building will connect to the existing system. Water samples were collected from both industrial wells on the Site as part of this investigation. Nitrate was detected in both samples at a concentration of 3.9 mg/L-N, well below the MCL of 10 mg/L-N. DBCP was not detected in either sample; the MCL for DBCP is 0.2 ug/L. Based on a review of San Joaquin County Environmental Health Department maps of nitrate and DBCP detections in nearby wells, it appears that nitrate has not been detected above the MCL within a half-mile radius mile of the Site, but DBCP has been detected above the MCL at one well within a half-mile radius. Additionally, Total Dissolves Solids (TDS) or "salt" contamination is known to be present in ground water beneath the adjacent Victor Meats facility to the north. Based on the current project, the use of on-site septic tanks and drain field systems on the Site is not expected to cause a buildup of nitrate in the aquifer above 1.6 mg/L-N. This level falls below the US EPA drinking water recommendation of 10 mg/L-N. We believe the Site suitable for the use of standard septic systems. Based on the satisfactory result of the nitrate loading calculation, no nitrate mitigation is recommended. LOGE 1912 Page 15