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On May 17, 1996, IT Corporation sampled the groundwater from the three monitoring wells This was the first recorded groundwater analytical data from these wells Groundwater samples ' from each of the wells contained concentrations of gasoline hydrocarbons including benzene The highest concentrations of TPH-gasoline (770 micrograms per liter(,ug/L)) and benzene (2 2 rug/L) were detected in MW-3 3,0 Groundwater Monitoring On September 27, 1996, groundwater from the three on-site wells was monitored and sampled ' A monitoring well construction summary for all of the wells installed at the site is presented in Table I and the well locations are illustrated in Figure 2 (Site Plan) Depth to groundwater ' measurements were taken in all three monitoring wells to evaluate groundwater flow and gradient characteristics The depth to groundwater at the site ranged from 31 90 to 37 64 feet bgs As such, the groundwater surface is above the screened interval of the three on-site wells ' On November 7, 1996, IT surveyed the three wellheads to a relative elevation of 100 feet Groundwater elevations beneath the site ranged from a high of 66 56 feet in MW-I and MW-2 to a low of 6149 feet in MW-3 On average, groundwater levels rose approximately 2 36 feet since the Iast monitoring event in May 1996 Groundwater flow was determined to be in a northerly direction at a gradient of 0 17 foot/foot The groundwater flow direction is consistent with the ' last monitoring event and the gradient increased 0 12 foot/foot A groundwater surface contour map is included as Figure 3 IT collected dissolved oxygen readings from each monitoring well using a downhole meter Dissolved oxygen concentrations ranged from 0 38 to 0 52 ppm A summary of groundwater monitoring data is provided in Table 2 4,0 Groundwater Sampling and Analyses ' All three on-site monitoring wells were sampled this quarter Monitoring wells MW-1, MW-2, and MW-3 were purged of at least three well volumes using a decontaminated electric ' downhole pump Groundwater Sampling Forms documenting well monitoring, purging, and sampling data are included in Appendix A 2