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Project 113-26-04,05,Page 9 November 17, 1995 After each well was developed, the bailer, pump, and down hole wiring and tubing were washed and operated in buckets with a TSP solution and rinsed twice in tap water Washing water was added to the drums Well purging and sampling was performed on September 25, 1995 First the well caps were removed from the wells The depth to water was measured at each location using an electronic sounding device with 0.01 feet accuracy. The sounder probe was washed and rinsed between wells Purging of the wells was accomplished by the removal of about 4-5 well volumes of groundwater (about 8-12 gallons) from wells MW-1, 2, 3, 5, 6, and 7 via an electric submersible pump operating at about 1-15 gpm About 40 gallons was removed from MW-8 Free product thickness of 0.02' was measured at MW-4 so the well was not sampled. None of the wells was drawn down more than a few inches during pumping at that rate. Groundwater was pumped directly into two septum vials per well The vials were filled until no head space remained and a positive meniscus was apparent. The vials were sealed, labeled, and placed into a cooler with ice for transport to the state certified analytical lab Chain of custody documentation and procedures were initiated Groundwater grab samples were obtained from the soil borings with a bailer The borings had been advanced about one foot beyond first encountered groundwater with the hand auger The bailer was cleaned between borings Groundwater was poured from the bailer into vials and handled as described above. At the Iab, all groundwater samples were analyzed for TPH as gasoline and BTEX Well Surveying, Groundwater Flow Direction The marks/notches at the top of the well casings were surveyed in October 1995 by a State Licensed Land Surveyor (Benchmark Consultants) to the nearest 0.001 foot, rounded to the nearest 0 01 foot (Table 2 Well Elevation Data). Elevations were shot from an established vertical datum (city benchmark) From the well elevations and depth to groundwater measurements, the elevation of the potentiometric surface was established relative to mean sea level (MSL) The top of casing elevations for the eight monitor wells range from 27 06 at MW-4 up to 29.28 feet above MSL at MW-3 Groundwater elevations at the wells ranged from 21 00 feet MSL at MW-1 and MW-4, to 2121 feet at MW-3 (Figure 3. Groundwater Elevation Data) Parker Environmental Services, 190 East 7th Street, Pittsburg, CA 94565-2317 Phone (510) 439-1024 Fax (510) 439-2566