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BC&D Properties j <br /> Report, MW Installation and Monitoring <br /> Project No. 8.1.2 <br /> December 17, 1992 ; <br /> Page 4 <br /> L <br /> 3.3 Hydrogeology of Site <br /> tOn November 13, 1992, groundwater level measurements were made and <br /> groundwater was found to be approximately 13 feet below the surface. <br /> Groundwater gradient was calculated using the three point method and was <br /> determined to be 0.00287 ft/ft flowing south 25° west (Figure 1). MW-4 is in a <br /> relative down gradient position at a distance of approximately 70 feet from the <br /> center of the former tank excavation. <br /> l 3.4 Contamination Distribution <br /> L <br /> r <br /> +The analytical data for the project have been tabulated and is presented as Table 1 <br /> in Appendix A. The supporting laboratory data sheets for the samples collected <br /> 1 L €during this scope of work are attached as Appendix C. <br /> 3.4.1 Soil <br /> {, ,A soil sample from the capillary fringe was submitted to GeoAnalytical } <br /> f 'Laboratories (State Certified Laboratory #E757) to be analyzed for benzene, <br /> + .;toluene, ethylbenzene and xylene (BTEX), and total petroleum hydrocarbons as <br /> F ;gasoline (TPH-Gasoline) analyses. The detection limits for the EPA 8020 (BTEX) <br /> ;analysis is 5.0 gg/kg and 2.5 mg/kg for TPH-Gasoline analysis. <br /> As the analytical data indicate, no contamination by petroleum hydrocarbons <br /> +was detected in the soil sample collected while drilling MW-4. This is consistent <br /> ij 'with the field observations recorded in the boring log (Appendix B). <br /> 'Therefore the non-detect analyses are consistent with the findings of earlier <br /> :sample data that indicated the soil contamination to be limited to the immediate <br /> vicinity of the former UST excavation area. <br /> 3.4.2 Groundwater <br /> C <br /> On November 13, 1992, all monitoring wells were purged and sampled by <br /> GeoAnalytical Laboratory personnel. <br /> ' L <br /> As the attached analytical data indicate (Appendix C), this round of groundwater <br /> 'sampling revealed no detectable hydrocarbons or lead in the groundwater <br /> samples from MW-1, 3 and 4. Slight amounts of aromatic petroleum <br /> f ;hydrocarbons were detected in MW-2 (benzene 2.1 gg/l, toluene 0.3 mg/l, and <br /> 'xylene 27 µg/1). Groundwater sampling procedure was performed in accordance <br /> - .:with the groundwater sampling protocols established by GeoAnalytical <br /> JLaboratory. <br /> I <br /> E? <br /> d <br /> i <br />