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I 'AWAWuAM /`A"VA Working to Restore Nature Residual gasoline hydrocarbons (quantified as total petroleum hydrocarbons as gasoline [TPHg]) were detected in soil samples at concentrations ranging from 12 parts per million (ppm) to 3,000 ppm Concentrations of TPHg are highest and more widespread near the I capillary fringe. Results of laboratory analyses are shown on Table 3, Hydrocarbon Concentrations in Soil Samples Collected From Soil Borings Results of soil samples collected from the tank cavity, product delivery lines, and dispenser islands are shown in I Table 4, Results of Soil Analyses of Former Tank Cavity and Product Line Trenches Sample locations are shown on Plate 8, Tank Excavation and Soil Sample Location. I 4.2 Extent of Hydrocarbons in Groundwater Results of subjective analyses of groundwater samples collected during the groundwater 1 monitoring events indicated floating product has not been present at the site since monitoring began (Table 1) Laboratory results indicate that dissolved gasoline hydrocarbons are present in groundwater in the five onsite wells (MW-1 through MW-5) and four offsite wells (MW-6, MW-7, MW-8, and MW-10) Concentrations of TPHg have 1 ranged from 55 parts per billion (ppb) to 18,000 ppb in the onsite wells and from below laboratory detection limits to 1,000 ppb in the offsite wells Concentrations of benzene have ranged from 15 ppb to 2,500 ppb in the onsite wells and were below laboratory detection 1 limits in the offsite wells The highest concentrations were detected in well MW-1, near the western property boundary Concentrations of TPHg and benzene for the November 29, 1993 monitoring event are shown on Plate 7, TPHg Concentrations in Groundwater (November 29, 1993) The analytical results are summarized in Table 5, Results of 1 Chemical Analyses of Groundwater Samples 1 30003-i3 7 1