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not detected. Analytical results are presented in Appendix A, Analytical Results of Soil Samples, From May 1989 through April 1992, twenty soil borings were drilled, eleven groundwater monitoring wells were installed, four nested vapor-extraction wells were installed, and a vapor extraction test performed (GTI, 1990 and GTI, 1992). Locations of soil borings, groundwater monitoring wells, and vapor extraction wells are shown on Figure 3. Analytical data indicated that soil samples collected from soil borings SB-1, SB-4, MW-2 through MW-5, and MW-7 through MW-11 did not contain concentrations of total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethylbenzene, and total xyIene isomers (BTEX) above the practical quantitation levels (PQL). Soil borings SB-2, SB-3, AB- 3, MW-1, and MW-6 contained detectable concentrations of TPHg and benzene (Appendix A). Soil samples were not analyzed from soil borings VEW-1 through VEW-4 because these borings were drilled adjacent to borings with previous analytical data. It is our understanding that groundwater monitoring wells MW-1 through MW-5 have been monitored from May 1989 through present and wells MW-6 through MW-11 have been monitored from May 1990 through present Well MW-1 has not been sampled because of the presence of free-phase hydrocarbons on groundwater. Free phase hydrocarbons have . periodically been removed from the well by balling Laboratory analyses from the samples collected from the groundwater monitoring wells have indicated that groundwater contains dissolved hydrocarbon concentrations. Analytical results are presented in Appendix B, Analytical Results of Groundwater Samples. The groundwater flow direction is mainly to east, northeast (GTI, 1993). In June 1992, GTI performed a vapor-extraction test (VET) utilizing the four nested vapor- extraction wells. According to GTI The results of the VET indicated that vapor extraction is feasible at the site. The radius of influence was approximately 25 feet at a flow rate of approximately 20 cubic feet per minute (cfm). The vapor concentrations of TPHg ranged from 3,300 to 30,000 milligrams per cubic meter (mg/m3). The laboratory results and monitoring data for the VET are presented in Appendix C, Vapor-Extraction Data. I 2.0 SITE CHARACTERISTICS The site surface is relatively flat and lies at an elevation approximately 10 feet above mean sea level. The geology and hydrogeology is based upon previous investigations in which soil borings were drilled and wells were installed by GTI 2.1 Subsurface Geology and Hydrogeology . Soil beneath the site from approximately 0 to 3 feet bsg consists of clayey sand, soil from 3 to 35 feet bsg soil consists predominantly of silty clay with layers of silt and sand, from r 35 to 43 feet bsg soil consists of clayey silt, and from 43 to 50 feet bsg soil consists of silty sand. The subsurface stratigraphy is shown on geologic cross-sections prepared by GTI and TEXSTOCK SRW SEAGOR2 X30001-006-01