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. Chevron site but rarely migrated southward beyond the southern edge of Country Club <br /> Boulevard, a distance of 100 feet or less. <br /> ® Gasoline concentrations in groundwater peaked in the middle 1990's, and have been on the <br /> decline for several years. Since the installation of a groundwater remediation system at the <br /> Chevron site, decline rates have been in the range of 30-40% each quarter at both sites. Five <br /> of seven monitoring wells at the Kwikee site have ,been free of Total Petroleum <br /> Hydrocarbons for two years or more, and only the two wells on the west side of the site, <br /> nearest the Chevron site, continue to be impacted. <br /> o MTBE, although present, is a relatively minor component of the groundwater plume and <br /> concentrations are considerably less than those of benzene. A strongly elevated <br /> concentration (9,200 ppb) was detected when groundwater entered the Kwikee tank pit and <br /> contacted the backfill material during tank removal, but well samples have been impacted at <br /> concentrations that are only 1-2% of this concentration, implying that there has been no <br /> massive leaching of MTBE downward to groundwater. Being much more soluble than <br /> benzene, MTBE should be present at much higher concentrations if it had been present in <br /> significant quantity in the gasoline release. This favors an older release, prior to extensive <br /> MTBE use. <br /> o The site has been adequately assessed to meet State regulations regarding site <br /> characterization. The regulations require that the site be sufficiently assessed to determine <br /> what, if any, corrective action is appropriate. Contamination is primarily limited to the <br /> western portion of the Kwikee site, and is already undergoing corrective action through the <br /> operation of the remediation system at the Chevron site. Any attempt to initiate a separate <br /> icorrective action would only complicate the operation of the Chevron system, and could be <br /> counterproductive by causing local perturbations in groundwater flow. Hence, corrective <br /> action is neither warranted nor advisable. <br /> fl Monitor wells KF-1, 3, and 5 should remain open to allow continued monitoring of water <br /> depths and periodic sampling. These should be monitored quarterly through 2003 and <br /> sampled semi-annually to confirm that gasoline concentrations are continuing to decline. <br /> All other wells can be abandoned without jeopardizing the monitoring program or creating a <br /> risk to public health. <br /> 26 <br />