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r Ile TPH-as-diesel and 4 ppm of TPH-as-gasoline The lateral extent of impacted soil is undefined to the north of Hamilton Alley Isoconcentration maps illustrating the distribution of TPH-as- diesel and TPH-as-gasoline in sod at a depth of 10 feet are included as Figures 3 and 4 Results of groundwater grab sample analyses indicate that significant concentrations of diesel and gasoline hydrocarbons exist in groundwater beneath the site and north of the site under Hamilton Alley The highest concentrations of diesel and gasoline hydrocarbons were detected to SB-3 immediately east of the former UST excavation Separate-phase hydrocarbons (i a free Product) were observed in SB-3 during the groundwater grab sampling operations The groundwater grab sample from SB-3 was analyzed in the laboratory by modified EPA Method 8015/8020 and found to contain 1,300,000 parts per billion (ppb) of TPH-as-diesel, 140,000 ppb of TPH-as-gasoline, 11,000 ppb of benzene, 18,000 ppb of toluene, 3,600 ppb of ethylbenzene, 18,000 ppb of xylenes and 400 ppb of MTBE All ten of the groundwater grab samples analyzed in the laboratory contained detectable concentrations of TPH-as-diesel and TPH-as-gasoline Laterally, the plume of impacted groundwater extends under Hamilton Alley to the north and the Meiring property to the east Isoconcentration maps for TPH-as-diesel in groundwater(Figure 5) and TPH-as-gasoline in groundwater (Figure 6) show that the plume has preferentially migrated to the northeast and that the plume boundaries are not defined 10