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In this report we have shown that almost no vadose-zone contamination has been detected at this site No contaminants have been detected shallower than about 20 feet, and concentrations have been very low Therefore,we believe that condition 1 above is met No separate phase product has ever been found at the site, and dissolved-phase concentrations have not been high enough to suggest that free product night be present Hence, condition 2 is satisfied As discussed in section 5 0, there are no surface water bodies or known wells that are in close proximity to the site in the downgradient direction Although some sewer lines are located close to the site, these are relatively shallow and are not a potential source of drinking water Hence,none of the potential receptors listed in condition 3 are threatened by pollutants remaining in the aquifer Whether the site meets Condition 4 is somewhat less certain at this time, because of conflicting results from different wells Changes in the concentrations of various contaminants have been documented, but the changes have not been predictable nor consistent and may reflect a complex interplay between changing groundwater levels, natural attenuation of hydrocarbons, and remedial activities For example, wells near the fringe of the plume (MW-1, MW-5) have shown a decrease in contaminant levels that suggests that the plume is shrinking and that there has been a net decrease in the total mass of contaminants remaining in the aquifer On the other hand, wells in the core of the plume (MW-2 and SW-1) have demonstrated no improvement in contaminant concentrations, even after remediation was performed Concentrations in MW-2 have been fairly stable since early 1996, but these concentrations are not significantly lower than those that existed at the beginning of the investigation in 1993 Given that MW-2 is located downgradient of the area of residual soil contamination, it is possible that concentration decreases resulting from natural attenuation and remediation are being offset by influx of contaminants from the soil,resulting in little or no net change in groundwater concentrations If this is the case, soil concentrations will decline over time and lead to a corresponding, though delayed, decrease in groundwater concentrations In view of the fact that all directives of San Joaquin County PHS/EHD that have been approved by the UST Cleanup Fund have been met and the evidence indicates that the site poses a low risk to the environment and to people, Upgradient Environmental recommends that PHS/EHD forward a No Further Action request to the Central Valley Board 10