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i Petroleum hydrocarbons as gasoline and/or diesel and toluene, ethylbenzene, and xylene were detected in laboratory analyses of ' all four samples from 81.7 (Table 3) . No benzene was detected in any of these samples. All contaminants reach maximum concentrations between 20 and 30 feet. Sample B17-43 (collected at a true depth of ' 37 feet from boring B17) emitted an unusual odor and was also analyzed for volatile halocarbons, but none were detected (Appendix B) . ' Gasoline and diesel concentrations in samples from B18 were much lower than those in B17 , and no hydrocarbons were detected in the deepest sample (40 feet) . The chromatograms were skewed slightly 1 toward the heavy end of the gasoline range, prompting the laboratory to interpret the results as indicative of older, degraded gasoline. Previous laboratories may have reported these or ' similar compounds as "kerosene" . No halocarbons were present, and volatile hydrocarbons were detected only in sample B18-35, at very low concentrations. ' Sample MW5-40, from a depth of 40 feet, was analyzed for total petroleum hydrocarbons and BTE&X. No contamination was detected. Figure 3 is a revised version of Figure 4 of WHF Environmental 's Monitoring Well Installation Report (Nov. 1992) . The revision incorporates the new data from B17 and B18 and corrects several ' errors in sample location in the original WHF figure. These corrections are discussed in Appendix C. Figure 3 shows that TPH-g and BTE&X concentrations increase to the north, and the highest concentrations detected to date occur beneath Harding Way in boring ' B17 . 4 . 3 Groundwater Sample Analysis ' The results of the groundwater sample analysis are shown in Figure 4 and Table 4 . Petroleum hydrocarbons in the diesel range were detected in the groundwater sample from MW-5, and hydrocarbons in both the diesel and gasoline ranges were detected in the water sample from MW--4 . , Tbluene was also detected in MW-4 . No other aromatic compounds were detected in any of the water samples. ' Toluene, ethylbenzene, and xylene were detected at concentrations near 1 ppb in the grab sample collected from the 55-gallon drum of purge water (D-9-11) . ' 4 . 4 Groundwater Elevation and Gradient The groundwater gradient and flow direction were calculated from the elevation data shown in Table 1 . These data agree well with those obtained in March and July 1993 , and confirm that groundwater flows to the northeast (Figure 4) . The present gradient is 0. 002 -ft/ft- 10