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1 <br /> Geofagzca(Tecrinus Inc Page 4 <br /> Groundwater Monitonng Report <br /> Project No 724 2 <br /> October 3,2002 <br /> ' samples were checked for headspace bubbles, labeled, inserted into foam holders and placed <br /> into an ice chest cooled to 4°C for transport to the laboratory <br /> The sampling technician while collecting all samples, wore disposab1e gloves <br /> es <br /> ' A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from field to the laboratory, thereby providing a means to track <br />' their movement and ensure their integrity <br /> 1.3 Laboratory Analyses <br /> The groundwater samples collected on June 21, 2002, were delivered to Sherwood Labs of <br /> Hilmar, California (certification#1400) for analyses of \ <br />' • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX), MTBE by EPA method 8020 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 8015(M) <br /> The detection limits for the above analyses are listed in Table 4 of Appendix A, while the <br /> lab analytical results are presented in Appendix B <br /> 2.0 FINDINGS AND DISCUSSION <br />' The results of the groundwater sample analysis show the following <br /> • Wells MW-1, MW-5, MW-6 and MW-104 did not contain contaminant concentrations <br />' above the laboratory reporting limits <br /> • Well MW-2 has trace amounts to low concentrations of the BTEX and TPH-G <br /> • Wells MW-3 and MW-4 contain trace concentrations of BTEX <br />' • MW-7 contained low levels of MTBE <br /> * Intermediate wells MW-106 and MW-107 contained trace BTEX concentrations and <br />' low TPH-G and MTBE concentrations <br /> 0 TPH-G was not detected in any of the water table wells(MW-4 through MW-7) <br /> • TPH-G was detected in intermediate wells MW-2, MW-106 and MW-107 Figure 5 — <br />' Intermediate Well TPH-G Concentrations - illustrates the extent of the TPH-G plume <br /> The shallow groundwater plume is evident in well MW-4 and defined laterally to the east <br /> (down gradient) by MW-5, MW-6 and MW-7 This situation is illustrated in Figure 6 — <br /> Water Table Well Benzene Concentrations Figure 7 -- Intermediate Well Benzene <br /> Concentrations & Figure 8 — Intermediate Well MTBE Concentrations suggest that a <br /> significant plume does not exist below the water table The presence of TPH-G <br /> contamination in well MW-106 and MW-107 suggests that a submerged plume is being <br /> sourced by residual soil contamination beneath the present water table It is noted that the <br />