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. Groundwater Extraction Well Installation summary Report page 2 The Southland Corporation 455 Grant Line Road Tracy_California December 6 1996 Transportation (DOT)-approved 55-gallon drums and left on site to be pumped through the groundwater treatment system 3 1 Soil Sampling Soil samples collected from the groundwater extraction well borings were collected at 5-foot Intervals beginning at approximately 5 feet BGS Samples were collected using a 2 5-inch O D split-spoon sampler, lined with three 2-Inch-diameter by 6-i.ich-long brass sample tubes The sampler was driven 18 inches ahead of the augers at each sample point Soil samples were field screened for hydrocarbon vapors using a photo-Ionization detector (PID) Soil was logged using the Unified Soil Classification System by a Fluor Daniel GTI field geologist working under the supervision of a California registered geologist (Appendix B) One sample tube from each 5-foot Interval was sealed, labeled and placed on ice in an insulated container for transport under chain-of-custody manifest to Western Environmental Science & and Technology (WEST) In Davis, California for analysis A total of seven soil samples were submitted for laboratory analysis of benzene, toluene, ethylbenzene and total xylenes (BTEX), methyl-tert-butyl-ether(MTBE) and total petroleum hydrocarbons as gasoline (TPH-G), using U S Environmental Protection Agency (EPA) methods 8020/modified 8015 Field notes are Included as Appendix C 40 GROUNDWATER MONITORING WELL INSTALLATION On October 23, 1996, groundwater extraction wells were installed In the two soil borings GWE-2, located over the former UST pit, and GWE-3, located between MW-9 and MW-10 (Figure 2) The groundwater extraction wells were constructed of 6-inch-diameter, schedule 40 polyvinylchloride (PVC) casing with flush threads, and 0 020-tnch-slot well screen The well screen was Installed In each boring from 4 feet to 14 feet BGS with a 5-foot sump, constructed of blank schedule 40 PVC, Installed from 14 to 19 feet BGS Sand was placed In each well annulus from the bottom to approximately 6 Inches above the top of the well screen The well annulus was sealed with approximately two feet of bentonite on top of the sand pack Prior to sealing the well annulus the well was surged to assure settling of the sand pack The wellheads are protected at the surface by locking, expandable well caps and 3-foot-square by 3-foot-deep traffic-rated street vaults Well construction details for groundwater extraction wells GWE-2 and GWE-3 are shown on the drill logs in Appendix S Well construction details for the 15 groundwater monitoring wells and three groundwater extraction wells at the site are summarized in Table 1 41 Monitoring Well Development and Surveying The wells were developed using a 6-inch surge block and a PVC bailer to remove fine-grained sediment from the well and sand pack Prior to development activities depth to water was measured 0?.311NST RPT)Sthl 5 1) ►-00. FLUOR DANIEL GTI j