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W� <br /> 2.0 FIELD SAMPLING SUNEViARY <br /> Groundwater samples were collected from monitor wells MW-2A and MW-9 (Figure 1-1) on <br /> 17 September 1998. Groundwater sampling data sheets are presented in Appendix B. <br /> Prior to sampling water levels in all wells were measured on 17 M <br /> p g arch. The standing water <br /> volumes within wells scheduled for sampling were then calculated using the water level <br /> measurements and total well depths. A submersible pump was used to purge three well casing <br /> volumes from monitor wells MW-2A and MW-9. MW-2 was not sampled because there was <br />' insufficient water to purge and sample <br />' At the beginning and during the purge process, the temperature, pH, and specific conductance <br /> of the purge water was measured. This information was recorded on a sampling data sheet <br />' Groundwater samples for benzene, toluene, ethylbenzene, and xylene (BTEX) and purgeable <br /> petroleum hydrocarbons as gasoline (TPH-G) analysis were collected from wells MW-2A and <br /> MW-9 with a disposable bailer and nylon string. The groundwater samples were transferred into <br /> 40 ml glass containers Sample containers were checked for air bubbles then sealed in a plastic <br /> bag, placed with ice in an insulated chest, and logged on a chain-of-custody form for delivery <br /> to the analytical laboratory <br /> The pump used to purge the wells was thoroughly cleaned prior to each use with a TSP solution <br /> followed by a potable water rinse and distilled water rinse. The disposable tubing was discarded <br /> after purging each well <br /> Purge water from monitor well MW-9 was stored in a holding tank located at 222 E. Weber <br />' Avenue The purge water stored in the holding tank was sampled and discharged to the sanitary <br /> sewer this quarter under a permit from the City of Stockton Department of Municipal Utilities <br /> Purge water from MW-2A was stored in a 55 gallon drum located at 100 N Hunter Street <br /> MW-2A purge water will be disposed of at a licensed treatment facility <br />' The groundwater samples collected from MW-2A and MW-9 were analyzed by EPA Method <br /> 8020 for BTEX and by EPA Method 8015M for TPH-G Groundwater sample analyses were <br />' performed by Sequoia Analytical Laboratory in Walnut Creek, California <br /> 1 <br /> L 1PROJECTASANJOQWSAW A"OCT 4 October 1998 <br />