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FWLIGEA3 ESIG.ERSTg6ClIM'5 ' 2.0 FIELD SAMPLING SUMMARY ' Groundwater samples were collected from monitor wells MW-2, MW-2A, MW-3A, MW-4, MW-6, MW-7, MW-8, and MW-9 (Figure 1-1) on 20 and 21 May 1997. Groundwater sampling data sheets are presented in Appendix B Monitor well MW-2 was not scheduled to ' be sampled because it is typically dry due to a drop in the groundwater table However, since groundwater was present in monitor well MW-2, it was sampled this quarter. Prior to sampling water levels in all wells were measured. The standing water volumes within ' wells scheduled for sampling were then calculated using the water level measurements and total well depths A submersible pump was used to purge three well casing volumes from all monitor wells except for MW-2 A Teflon bailer was used to purge monitor well MW-2 because of the ' small purge volume ' At the beginning and during the purge process, the temperature, pH and electrical conductivity of the purge water was measured This information was recorded on a sampling data sheet ' After purging the well a groundwater sample was collected with a Teflon bailer and disposable nylon string The groundwater sample was transferred into 40 ml glass sample containers • Sample containers were checked for air bubbles The sample containers were sealed in a plastic bag, placed with ice in an insulated chest, and logged on a chain-of-custody form for delivery to the analytical laboratory The um used to purge and sample the wells was thoroughly cleaned prior to each use by pump P g P placing it into a container of tap water, washing the outside, and pumping water and Alconox through the pump and attached hose Tap water was then pumped through the pump and hose. ' Purge water from monitor wells MW-2, MW-3A, MW-4, MW-6, MW-7, MW-8, and MW-9 was stored in a holding tank located at 222 E Weber Avenue Purge water stored in the holding ' tank will be sampled and discharged to the sanitary sewer at a later date under a permit from the City of Stockton Department of Municipal Utilities Purge water from MW-2A was stored ' in a 55 gallon drum located at 100 N. Hunter Street MW-2A purge water will be disposed of at a licensed treatment facility All groundwater samples were analyzed by EPA Method 8020 for benzene, toluene, ethylbenzene, and xylenes (BTEX) and by EPA Method 8015M for total petroleum hydrocarbons ' as gasoline (TPH-G) The analyses were performed by American Environmental Network in • Pleasant Hill, California L TROJECT=ANJOQISJCIISA 4TH 4 July 1997