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Groundwater samples were collected from the monitoring wells by EMC personnel on February <br /> 29, 1996 Prior to sample collection, at least three well volumes of groundwater were removed <br /> from each well by a portable submersible pump or bailer All equipment was cleaned using a <br /> solution of Alconox and water followed by two tap water rinses The actual groundwater <br /> samples were collected with a teflon bailer equipped with a bottom emptying device before being <br /> transferred into the laboratory supplied 40 ml VOA vials pending analyses The chain-of- <br /> 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 /> The samples were analyzed for total hydrocarbons (TPHg) and volatile aromatic compounds <br /> (BTEX) by EPA methods 8015 and 8020, respectively Table 1 presents a summary of the <br /> TPHg and BTEX data The complete laboratory reports for the current samples are included <br /> in Appendix B <br /> Results of analysis indicate wells only MW3 and MW5 had detectable levels of TPH and <br /> benzene, except for MW9 which had 0 49 ppb benzene The highest concentration of benzene <br /> was found in MW3 with 1,200 ppb A benzene iso-con map is presented on Figure 2 <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 date suggest the flow direction of groundwater across the site is generally to the <br /> east-southeast Thrifty will continue to monitor the on-site wells on a quarterly basis If you <br /> have any questions, please contact Raymond C Fnednchsen at (310) 923-9876 ext 376 <br /> Very truly yours, <br /> Peter D'Amico <br /> Manager Environmental Affairs <br /> cc CVRWQCB, Elizabeth Thayer <br />