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Groundwater samples were collected from the on-site wells by EMC 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 baler equipped with a bottom emptying device <br /> before being transferred into the laboratory supplied 40m1 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 Smith-Emery <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 two of the four wells on-site. TPHg concentrations <br /> of 56,000 ug/L and 8,000 ug/L were noted in groundwater from wells MW-2 and MW-3, <br /> respectively. Detectable BTEX concentrations ranged from 150 ug/L to 14,000 ug/L with the <br /> highest cgncentrations noted in well MW-2 No detectable TPHg or BTEX were noted in <br /> samples from MW-1 and MW-4 A benzene iso-con map is presented on Figure 2. A decrease <br /> in the dissolved hydrocarbons concentrations was noted this quarter <br /> CLOSING <br /> Based on the site investigation and monitoring program, it appears that the shallow water zone <br /> found beneath the site exhibits the presence of dissolved hydrocarbons. The monitoring events <br /> accomplished to data suggest the flow direction of groundwater across the site is generally to the <br /> south and east-southeast. Thrifty will continue to monitor the on-site wells on a quarterly bass <br /> If you have any questions, please contact me at (310) 923-9876. <br /> Very truly yours, <br /> Peter D'Amico <br /> Manager <br /> Environmental Affairs <br /> cc CVRWQCB, Elizabeth Thayer <br />