Laserfiche WebLink
SECOND QUARTER 1996 <br /> QUARTERLY MONITORING REPORT <br />' USA PETROLEUM STATION #65- LODI <br /> MAY, 1996 <br /> To reduce the potential for cross contamination between 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 appeared to stabilize in the purged <br /> groundwater <br /> 4.3 Groundwater Sampling <br /> P g <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 and BTEX, using EPA methods 8015 Modified <br />' and 8020, respectively The analyses were conducted by Sierra Laboratories, Inc (Sierra) a <br /> California State certified laboratory in accordance with state guidelines and EPA protocol <br /> r5.0 SUMMARY AND CONCLUSIONS <br /> The following sections discuss findings from the groundwater gauging and sampling activities <br /> conducted on April 18, 1996 <br />' 5.1 Groundwater Flow and Gradient <br /> Groundwater data collected at the site indicates that the depths to groundwater ranges from 41 91 <br />' to 44 13-feet bgs The groundwater elevations range from 6 25 to 4 92-feet below MSL The <br /> direction of groundwater flow has been calculated to be trending to the south with an average <br /> hydraulic gradient of approximately 0 0023-ft/ft across the site Histonc field data suggests that <br />' groundwater generally flows to the south with minor fluctuations to the east and west as shown <br /> on Figures 3 and 4 <br /> 4 <br /> 1 <br />