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raised to 100 ppb. A similar problem affected the samples from MW-3 and MW-8, where the detection limit was raised to 10 ppb. Therefore, only the plume in the vicinity of MW-1 could be mapped. This plume extends eastward onto the Kwikee site, where MTBE was detected in KF-3 at the same concentration as in MW-b, and at lower concentrations in KF-5 and KF-2. The center of this plume is somewhat difficult to resolve definitively with the existing well spacing. It appears to be located just east of MW-1, where concentrations exceeding 100 ppb may be present, and that interpretation is compatible with the historical record of the groundwater flow direction (Figure 4). The fact that MTBE extends slightly farther eastward than do the other hydrocarbons is also compatible with the fact that MTBE is more soluble in groundwater, and therefore travels more rapidly in the prevailing direction of groundwater flow. if the MTBE had originated at the Kwikee site, it would be difficult to explain the fact that the highest MTBE concentration was detected in MW-1 at the Chevron site. Further, the fact that the maximum MTBE concentration (100 ppb or ` less) is relatively low is consistent with the fact that the Chevron site was abandoned in the early 1990's, before MTBE became a major component of gasoline. If a release had occurred at Kwikee Foods, MTBE concentrations should be considerably higher there than at the Chevron site, since Kwikee Foods continued to sell unleaded gasoline into the late 1990's. 5.0 CONCLUSIONS ANIS RECOMMENDA71ONS The data collected during the first quarter of 2002 provide additional support to our previous interpretation that hydrocarbon concentrations in the groundwater below the Kwikee Foods site are declining rather steadily. Benzene concentrations are below the Maximum Contaminant Level in five of the seven wells at the site, and concentrations decreased this quarter in all wells except KF- 5. PHS/EHD has recently raised the question as to whether residual soil contamination upgradient of KF-3 might be present and continuing to leach downward to groundwater. This concern was based on the concentrations detected in November 2001, which were higher than they had been in the previous quarter. In its January 2002 review letter, PHS/EHD stated that "This pattern of increasing concentrations of MTBE and TPH-g in KF-3 samples as groundwater flows to the west doesn't support your consultant's conclusion that Chevron is responsible for all the groundwater contamination at Kwikee." This statement ignores the fact that KF-3 has experienced a 99% decrease in concentrations since monitoring began in 1994. This decline is real, and is due largely to natural attenuation, but has been supplemented recently by active remediation of the former Chevron site at 2103 Country Club Boulevard. The February data indicate that the November increase was merely a typical quarter-to-quarter fluctuation rather than a "pattern of increasing concentrations". Hence, the February data reaffirm our conclusion that soil contamination beneath Kwikee Foods is inconsequential. Further, if any of the groundwater contamination at Kwikee originated there, it is so minor as to be indistinguishable from the much more contaminated groundwater that has migrated eastward from the Chevron site.