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Groundwater samples were collected from the on-site wells by FMC personnel Prior to sample <br /> collection, at least three well volumes of groundwater were removed from each well by a <br /> portable submersible pump or bailer During the purging of groundwater, pH, conductivity, <br /> temperature and turbidity were monitored at selected intervals. This data is included in <br /> Appendix A along with the gauging data for the reporting period. All equipment was cleaned <br /> using a solution of Alconox and water followed by two tap water rinses The actual <br /> groundwater samples were collected with a teflon bailer equipped with a bottom emptying device <br /> before being transferred into the laboratory supplied 40ml VOA vials pending analyses. The <br /> chain-of-custody documentation is presented in Appendix B. <br /> ANALYTICAL DATA <br /> Each groundwater sample was transported on ice in a light proof chest to American Analytics <br /> Laboratory. The samples were analyzed for total hydrocarbons (TPHg) and volatile aromatic <br /> compounds(BTEX) by EPA methods 8015 and 8020, respectively. Table 1 presents a summary <br /> of the TPHg and BTEX data. The complete laboratory reports for the current samples are <br /> included in Appendix B <br /> The results indicate the presence of TPHg in all four wells on-site (ranging from 320 ug/L to <br /> 21,000 ug/L). Benzene concentrations ranged from 40 ug/L to 4,700 ug/L with the highest <br /> concentration noted in well MW-2 A benzene iso-con map is presented on Figure 3. An <br /> increase m the dissolved hydrocarbons concentrations was noted this quarter This increase <br /> could be a result of rise in groundwater beneath the site <br /> CLOSING <br /> Based on the resent site investigation and monitoring program, it appears that the shallow water <br /> zone found beneath the site exhibits the presence of dissolved hydrocarbons. The monitoring <br /> events accomplished to data suggest the flow direction of groundwater across the site is generally <br /> to the south and south east. Thrifty will continue to monitor the on-site wells on a quarterly <br /> basis If you have any questions, please contact me at (310) 923-9876 <br /> Very truly yours, <br /> //,-j <br /> C� '��G_Z'�b <br /> Peter D'Amico <br /> Manager <br /> Environmental Affairs <br />