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Both wells were constructed with a filter pack of Monterey#3 graded and washed sand to three feet above the top of the screened intervals Overlying the sand pack in both wells, a layer of hydrated bentonite chips was installed approximately two feet thick A surface seal of neat cement grout was placed over the hydrated bentonite The tops of the wells were secured and locked with watertight caps Monitoring well MW-6 was completed with an 8-inch diameter, flush-mount traffic box and MW-7 was completed with a 5-foot stove-pipe monument casing Dunng drilling, the sod cuttings were logged according to the Unified Soil Classification System by a geologist and screened using an organic vapor monitor equipped with a photoionization detector(PID) Monitoring well logs are included as Appendix C 2 2 2 Soil Sampling and Analysis During the drilling of both sod borings, soil samples were collected using a modified California split-spoon sampler, lined with brass sleeves Since the sod borings were located outside of the defined plume of impacted soil, soil samples were only collected in each soil boring at 40 and 45 feet bgs To evaluate the condition of sod below the groundwater table, the soil samples collected from 45 feet bgs from each soil boring were submitted for laboratory analysis Both sod samples were labeled, packaged in an iced cooler, and transported under chain-of- custody documentation to American Environmental Network (AEN), a state of California certified hazardous waste testing laboratory (DOHS #1172) AEN analyzed each of the groundwater samples for TPH-as-Gasoline, benzene, toluene, ethylbenzene, xylenes (BTEX) and MTBE by modified EPA Method 8015/8020 and for the alcohol- and ether-based oxygenate compounds by EPA 8260 2 2 3 Well Development and Elevation Survey During well construction, immediately following the placement of the sand filter packs, each well was surged by the driller for approximately 20 minutes On May 1, 1998, after the groundwater monitoring wells were completed and the grout seal had set, the wells were pumped with an electric downhole (Grunfos) pump The wells were considered developed once the sediment in the discharged groundwater had cleared and after at least five well volumes had been pumped Approximately 25 gallons (approximately 8 well volumes) of groundwater were actually pumped from each well During groundwater pumping from both wells a stable draw down of approximately 2 feet was maintained at a sustained pumping rate of approximately 4 gallons per minute (gpm) The purged groundwater from each well was contained in separate 55-gallon 1 0 drums and stored on-site pending proper disposition 7