ARCHIVED REPORTS_XR0003908 - Laserfiche WebLink

Home Browse Search

QUARTERLY MONITORING REPORT USA STATION#65-LODI APRIL, 1996 4.1 Groundwater Elevations ' Prior to gauging depths to groundwater, the monitoring wells were checked for the presence of free floating hydrocarbon product using a new disposable bailer Depths to groundwater measurements were then taken from each well from surveyed marks on the casing using an electric water level sensor or interface probe Field data and calculated groundwater elevations are presented in Table 1 Field data sheets completed during the gauging activities are included in ' Appendix A 4.2 Monitoring Well Purging ' The monitoring wells were purged using a 2-inch diameter, disposable hand bailer, until a minimum of three equivalent well volumes of water were removed from each well Groundwater purged from the wells was placed into DOT approved 55-gallon drums and stored on-site prior to disposal by USA To reduce the potential for cross contamination between wells, all purging and sampling equipment was washed in a tnsodium phosphate solution and rinsed in potable water ' prior to each usage During the groundwater purging operations, physical parameters such as pH, temperature and conductivity were monitored and recorded on field data sheets 4.3 Groundwater Sampling Prior to sampling the wells were allowed to recharge to a minimum of 80 percent of their initial ' static water levels Groundwater samples were collected from each well using a new disposable bailer Samples were placed into the appropriate laboratory prepared containers, using proper sample handling and chain-of-custody(COC) protocol established under applicable SW-846 procedures issued by the USEPA The samples were labeled with the date, time and identifying well number, stored in a cooler at 4° Centigrade or less, and transported to a state certified laboratory under completed COC documentation 4.4 Groundwater Analyses Groundwater samples were analyzed for TPH G and BTEX, using EPA methods 8015 Modified and 8020, respectively The analyses were conducted by Sierra Laboratories, Inc (Sierra) a ' California state certified laboratory in accordance with state guidelines and EPA protocol 5.0 SUMMARY AND CONCLUSIONS The following sections discuss findings from the groundwater gauging and sampling activities conducted on January 26, 1996 4