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wWNGE19 SY.NERS�`Eli11w15 ' 2.0 FIELD SAMPLING SUMMARY • ' Groundwater samples were collected from monitor wells MW-2A, MW-3A, MW-4, MW-5, MW-6, MW-7, and MW-9 (Figure 1-1) on 17 and 18 June 1998. Groundwater sampling data ' sheets are presented in Appendix B. ' Prior to sampling, water levels in all wells were measured on 17 June 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 each of the monitor wells. ' At the beginning and during the purge process, the temperature, pH, and specific conductance of the purge water was measured. This information was recorded on a sampling data sheet ' Groundwater samples for benzene, toluene, ethylbenzene, and xylene (BTEX) and purgeable petroleum hydrocarbons as gasoline (TPH-G) analysis were collected from the wells with a disposable bailer and nylon string The groundwater samples were 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 Iaboratory. The pump used to purge and sample the wells was thoroughly cleaned prior to each use by placing it into a container of tap water and washing the outside of the pump The disposable hose was discarded after purging each well. ' Purge water from monitor wells MW-3A, MW-4 MW- - g to e s MW 3 , 5, MW 6, MW-7, and MW-9 was stored ' in a holding tank located at 222 E Weber Avenue The purge water stored in the holding tank will be sampled and discharged to the sanitary sewer prior to the next quarterly sampling event ' 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 The groundwater samples were analyzed by EPA Method 8020 for BTEX and by EPA Method ' 8015M for TPH-G. Groundwater sample analyses were performed by American Environmental Network in Pleasant Hill, California. 1 L TROlEC rWANJOQWSA\HSA_99JUN 4 July 19% 1