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SECOND QUARTER, 1997 ' <br /> GROUNDWATER MONITORING REPORT <br /> USA STATION#65-LODI ' <br /> JUNE, 1997 <br /> During the groundwater purging operations, physical parameters such as pH, temperature and <br /> 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-then collected-from each=well using-a-new t <br /> disposable bailer The samples were placed into the appropriate laboratory prepared containers, <br /> using proper sample handling and chain-of-custody (COC) protocol established under applicable <br /> SW-846 procedures issued by the USEPA The samples were labeled with the date, time, <br /> identifying well number, stored in a cooler at 4° Centigrade or less, and transported to a state <br /> certified laboratory under completed COC documentation <br /> 4.4 Groundwater Analyses <br /> Groundwater samples were analyzed for TPH G, MTBE and BTT-Y, using EPA Method 8 ' <br /> $ s 015 <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 April 14, 1997 <br /> 5.1 Groundwater Flow and Gradient ' <br /> Groundwater data collected at the site on April 14, 1997 indicate that the depths to groundwater , <br /> ranged from 39 53 to 41 53-feet bgs The groundwater elevations ranged from 2 53 to 3 65-feet <br /> below MSL <br /> The direction of groundwater flow has been calculated to the south southeast with an average <br /> hydraulic gradient of approximately 0 003-ft/ft across the site Historic field data suggests that <br /> the groundwater generally flows southerly, with minor fluctuations to the east and/or west, as <br /> shown on Figures 3 and 4 <br /> 5.2 Results of Groundwater Laboratory Analyses <br /> The April 14, 1997 analytical results detected TPH G in six of the ten monitoring wells sample <br /> (MW-2, MW-3, MW-4, MW-8, S-1, and S-2) <br /> 4 <br />