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REG 603 UPDATE-6 2/21/92 In order to "purge', each well, a dedicated disposable PVC 1 1/211 x 31 bailer was repeatedly lowered down the well and into the water. Temperature, pH, and conductivity was measured for every third bailer volume removed. Balling proceeded for each well until pH, conductivity, and temperature parameters stabilized (approximately 5 gallons) and then the sample was taken. During the September 17, 1991 sampling the pH probe malfunci.tioned also MW2 was depleted and did not recharge until the following day, at which time the sample was obtained, see Appendix C. The "purged" water is presently being stored in the 1000 gallon "ConVault" , on site, within the fenced treatment compound. A representative water sample was obtained from the monitor wells using the dedicated disposable PVC bailer used during purging of the well. The water samples collected were stored in four-40 milliliter VOA vials. These water samples were placed into an insulated cooler with ice and, in the clients behalf, "chain of custody hand delivered" to Chemtech Analytical Laboratories (DHS certified #359 ) for chemical analyses. 3 .0 RESULTS 3 . 1 PRODUCT AND RECOVERY During the initial site assessment and during subsequent site visits, floating product was observed in monitor wells MW-1, MW-3 and MW10 . Product thickness in MW-1 has ranged from 0 . 021 to 1.261 and from 0. 61 to 1.661 in MW--3 . Only a product sheen has been observed in MW10 during the March, June and September, 1991 samplings. The recovered gasoline is amber yellow and appears to be fresh (no apparent degradation) . Involved regulatory agencies suggested that product recovery commence before an aquifer pump test be performed. Temporary submersible pneumatic pumps were installed into monitor wells MW-1 and MW-3 for product recovery on October 10, 1989. Approximately 40 gallons of gasoline was recovered. The product II V ..aa. aiii1 GI.Ji 6L4AL Y , 1 �� l, te-recovs-nr --tem y- 1 " L. b . a. 74-in HM"17aU tli 411 tank, until September, 1990 , was being used for the storage of the purged well water. On May 25, 1990 a water sample obtained from the "ConVault" indicated that the stored water was free of petroleum hydrocarbons (Table 1 Convault) . This water was later dumped to the sewer after permission was obtained by the Stockton Department of Municipal Utilities (approximately 250 gallons) . During the November 27, 1990 monitoring round, 0 . 081 of a clear t yellow floating product was again discovered in monitor well MW1. This well was purged until depletion of the product was noted; approximately 1 quart of gasoline was recovered and placed into PAGE 5