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benzene concentration is now only 0.3% of its value three years ago (July 2000) and the TPH-g • concentration is 2.5% of its July 2000 value. This represents a decline of more than 97%. The MTBE concentration is still about 17% of its value in 2000, an indication of the persistence of this compound in groundwater. The laboratory did not detect 1,2-DCA in any of the samples. Of the 25 samples that have been analyzed for this compound at the Kwikee site, only 3 contained the hydrocarbon above the detection limit. The highest concentration (2.6 ppb) was detected in KF-3 in May of 2002, during the period when the Chevron remediation system was inoperative. Gettler-Ryan provided laboratory data for the adjacent Chevron site. Gasoline concentrations in Chevron wells MW-1, MW-2, MW-6, MW-7, and MW-8 declined slightly, while concentrations in MW-3 and MW-4 increased. These results do not match with predictions based on the groundwater elevation data, a circumstance that we cannot explain. Overall, the changes did not significantly affect the shape of the dissolved-phase plume, and the gasoline distribution is basically unchanged from the past few quarters (Figures 5 and 6). The core of the main plume is centered near the eastern boundary of the Chevron site. In this area, the benzene/TPH-g ratio has normally ranged from about 10% in MW-1 to as much as 45% in MW-6 in the past several quarters. This ratio decreases away from the core of the plume to between 1 and 5% in most of the other Chevron wells and in KF-3 and KF-5. A second plume is probably present bordering the western side of the Chevron site, as indicated by the elevated concentrations in MW-4. No 1,2-DCA was detected in any of the Chevron wells, and it appears that this is not a contaminant of concern at either site. The remediation-induced groundwater sink is no longer present beneath the former Chevron site. and has been replaced by a narrow, linear mound in the water table that trends northeastward from the south-central part of the Chevron site to the northeastern corner of the Kwikee site. Groundwater flow is parallel to this ridge, as well as transverse to it (perpendicular to groundwater elevation contour Iines). The ridge is centered above the UST cavity at the Chevron site, near the core of a plume of gasoline-contaminated groundwater. Diffusion of gasoline constituents along groundwater flow lines probably accounts for the appearance of MTBE in KFA and slight increases in the concentrations of various hydrocarbons in KF-3, although the flow pattern should have produced analogous increases in MW-6 and MW-7 but did not. According to San Joaquin County EHD, data from one or more sites to the west of Kwikee Foods indicate that deeper aquifers have been impacted 6y gasoline at those sites. Borings drilled at those sites encountered extensive contamination in the unsaturated zone, and the presence of hydrocarbons in deeper aquifers implies that one or more vertical migration pathways are present. These conditions do not exist at Kwikee; almost no contamination has been detected in soil samples from the unsaturated zone outside of the UST tank pit or from the saturated zone (including those from beneath and near the tank pit). Hence, there is no evidence of a source of contaminants that 5