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FORTH QUARTER 1996 <br /> QUARTERLY MONITORING REPORT . <br /> USA STATION#65 -LODI <br /> NOVEMBER, 1996 <br /> 4.2 Monitoring Well Purging <br /> The monitoring wells were purged using a 2-inch diameter submersible Grundfos groundwater <br /> pump until a minimum of three equivalent well volumes of water were removed from each well <br /> Groundwater purged from the wells was placed into DOT approved 55-gallon drums and stored <br /> on-site prior to disposal by USA <br /> Ta reduce the P otentiai-for crass eontanunatiorrbetween wells;all-purging and°sampling <br /> equipment was washed in a tnsodium phosphate solution and rinsed in potable water prior to each <br /> usage During the groundwater purging operations, physical parameters such as pH, temperature <br /> and conductivity were monitored and recorded on field data sheets Groundwater purging was <br /> discontinued when the physical parameters indicated above stabilized in the purged groundwater <br /> 4.3 Groundwater Sampling <br /> Prior to sampling, the wells were allowed to recharge to a minimum of 80 percent of their initial , <br /> static water levels Groundwater samples were collected from each well using a new disposable <br /> bailer Samples were placed into the appropriate laboratory prepared containers, using proper <br /> sample handling and chain-of-custody(COC) protocol established under applicable SW-846 <br /> procedures issued by the USEPA The samples were labeled with the date, time and identifying <br /> well number, stored in a cooler at 4' Centigrade or less, and transported to a state certified <br /> laboratory under completed COC documentation <br /> 4.4 Groundwater Analyses , <br /> Groundwater samples were analyzed for TPH G, MTBE and BTEX, using EPA Methods 8015 <br /> Modified and 8020, respectively The analyses were conducted by Sierra Laboratories, Inc <br /> (Sierra), a California State certified laboratory in accordance with state guidelines and EPA <br /> protocol <br /> 5.0 SUMMARY AND CONCLUSIONS <br /> The following sections discuss findings from the groundwater gauging and sampling activities <br /> conducted on October 10, 1996 <br /> 5.1 Groundwater Flow and Gradient <br /> Groundwater data collected at the site on October 10, 1996 indicate that the depths to <br /> groundwater ranged from 42 64 to 45 00-feet bgs The groundwater elevations range from 7 12 <br /> to 5 63-feet below MSL <br /> 4 <br />