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C L EARWAX ER <br /> C R O L P, I N C <br /> 10 _. <br /> custody form, and placed on ice in a cooler for transport to the protect laboratory <br /> All groundwater samples were analyzed by Trace Analysis Laboratory, Inc for <br /> concentrations of TPHg, BTEX, and methyl tertiary-butyl ether (MTBE) according to <br /> EPA Method 8015/8020 (modified) <br /> 3.0 RESUL'T'S OF RECENT INVESTIGATION <br /> 3.1 Subsurface Sedimentology <br /> In general, subsurface soils encountered during drilling consisted of interbedded <br /> sandy silt and silty sand silt from the ground surface to a depth of approximately 25 <br /> feet below grade Individual beds of the coarser silty sands appear to be laterally <br /> discontinuous Below approximately 25 feet below grade, a silty sand was present to <br /> a depth of 30 feet below grade, the maximum depth explored Groundwater was <br /> present at a depth of approximately 16 feet below grade A geologic cross section <br /> 1 across the site is presented on Figure 3 Subsurface observations corresponding'the <br /> three wells reported here are presented on the boring logs, included in Appendix A <br /> 3.2 Soil Sample Analytical Results <br /> The soil sample collected from RW-1 at a depth 14 5 feet below grade contained <br /> detectable levels of TPHg and BTEX The TPHg and benzene concentrations were <br /> 450 parts per million (ppm) and 6 1 ppm, respectively Soil sample analytical results <br /> are summarized on Table 1 The certified analytical reports are presented with the <br /> chain of custody in Appendix B <br /> 3.3 Groundwater Gradient <br /> 3 3 1 4th Quarter 1995 <br /> On October 19, 1995, the depth to groundwater in each of the wells ranged from 13 71 <br /> (MW-3) to 15 21 (MW-7) feet below grade Depth to water measurements and <br /> previously surveyed wellhead elevation data were used to calculate the <br /> groundwater elevation contours shown on Figure 4 Groundwater flow beneath the <br /> site was toward the northwest at a general gradient of 0 0022 <br /> 3.3 2 1st Quarter 1996 <br /> I On January 5, 1996, the depth to groundwater in each of the wells ranged from 15 61 <br /> (MW-3) to 17 05 MW-7) feet below grade Depth to water measurements ancT' <br /> previously surveyed wellhead elevation data were used to calculate the <br /> groundwater elevation contours shown on Figure 5 Groundwater flow beneath the <br /> site was toward the northeast at a general gradient of 0 0015 Groundwater <br /> elevations are summarized with historical data on Table 2 <br />' D-107, PAR RAP <br /> / 5 February 21, 1996 <br /> I <br />