Laserfiche WebLink
THIRD QUARTER,1997 <br /> GROUNDWATER MONITORING REPORT <br /> USA STATION#110-STOCKTON <br /> SEPTEMBER,1997 <br /> 2.2 Monitoring Well Purging <br /> The monitoring wells were purged using a 2-inch diameter, submersible Redsflo groundwater <br /> pump, until a nummum of three equivalent well volumes of water were removed from each well ' <br /> MW-1 and MW-2 were not purged before sampling due to the linuted amount of groundwater <br /> present in the wells Groundwater purged from the wells was placed into Department of <br /> Transportation approved 55-gallon drums and stored on-site prior to disposal by USA All <br /> purging and sampling equipment was washed in a tnsodium phosphate solution and rinsed in <br /> potable water prior to each usage to reduce the potential for cross contamination between wells <br /> During the groundwater purging operations, physical parameters such as pH, temperature and <br /> conductivity were monitored and recorded on field data sheets, which are included in Appendix <br /> A Groundwater purging was discontinued when the physical parameters appeared to stabilize in <br /> the purged groundwater <br /> 2.3 Groundwater Sampling <br /> Prior to sampling, the wells were allowed to recharge to a minimum of 80 percent of their initial <br /> g <br /> static water levels (SWLs) Groundwater samples were collected from MW-1, MW-2 and MW- <br /> 1-P through MW-6-P using a new disposable bailer Samples were placed into the appropriate <br /> laboratory prepared containers, using proper sample handling and chain-of-custody (COC) <br /> protocol established under applicable SW-846 procedures issued by the USEPA The samples <br /> were labeled with the date, time, identifying well number, then stored in a cooler at 4° Centigrade <br /> or less, and transported to a state certified laboratory under completed COC documentation <br /> 2.4 Groundwater Analyses <br /> Groundwater samples were analyzed for TPH G and BTEX using EPA Methods 8015M and <br /> 8020, respectively The analyses were conducted by Sparger Technology, Inc (Sparger) a <br /> California State certified laboratory in accordance with state guidelines and EPA protocol <br /> 3.0 SUMMARY AND CONCLUSIONS <br /> The following sections discuss findings from the groundwaterg g g ansam hn au in d activities <br /> p g <br /> conducted on July 30, 1997 <br /> 3.1 Groundwater Flow and Gradient <br /> Groundwater data collected at the site indicates that depths to groundwater ranged from 64 25 to <br /> 65 51-feet below ground surface (bgs) <br /> 2 <br /> 1 <br />