Laserfiche WebLink
THIRD QUARTER 1996 <br /> QUARTERLY MONITORING REPORT <br /> USA STATION#65 - LODI <br /> SEPTEMBER, 1996 <br /> 1 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 /> To reduce the potential for cross contamination between wells, all purging and sampling <br /> equipment was washed in a trisodium 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 /> 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 /> 5.0 SUMMARY AND CONCLUSIONS <br />' The following sections discuss findings from the groundwater gauging and sampling activities <br /> conducted on July 18, 1996 and then again on August 19, 1996 Due to unusual analytical results <br /> for MW-3, MW-7 and MW-8 during the July 18, 1996 sampling event, the site was resampled <br /> Park was concerned that samples had been inadvertently switched <br /> 4 <br />