ARCHIVED REPORTS_XR0007887 - Laserfiche WebLink

Home Browse Search

Hydrocarbons in soils and Ground Wats In soils, TPH as gasoline or diesel and BTEX compounds have only been detected in borings MW- 1A, MW-2A (only very low concentrations of benzene, ethylbenzene, and xylenes were detected in boring MW-2A at a depth of 10 feet), MW- 3A, and B3-A No hydrocarbons and associated compounds were detected in soils from any other borings The highest concentrations of chemicals in soils is centered around boring MW-3A which is located a significant distance east of the former underground tank The source of the affected soil is unknown In addition, the geophysical survey found no evidence of any buried objects or debris in that vicinity The vertical occurrence is primarily limited to the 5-to-7 5-foot bgs depth interval The site cross sections in Figures 3-5 and 3-6 display the estimated vertical extent of hydrocarbons in the soil Figures 3-7 and 3- 8 display the estimated horizontal extent of hydrocarbons in the soil at depths of 5 and 7 feet bgs, respectively Figure 3-9 shows the estimated horizontal extent of hydrocarbons in the ground water TPH as gasoline was detected in only 4 of 21 soil samples TPH as diesel was only detected in soil samples collected from boring MW-1A The maximum concentration of TPH as diesel was measured as 180 mg/kg at a depth of 5 feet BTEX compounds were detected in 5 of 21 soil samples The occurrence of BTEX compounds was limited to the same samples which contained TPH as gasoline The occurrence in ground water of TPH as gasoline and diesel has been limited to wells MW-1A and MW-2A No TPH as gasoline or diesel or BTEX compounds have been detected in ground water samples collected from MW-3A, MW-4A, and MW-5A The concentrations of both constituents in well MW-1A have fluctuated over time Concentrations of TPH as gasoline in monitoring well MW-1A have fluctuated between 23 and 50 mg/l between April 1992 and April 1993, and the concentrations of TPH as diesel have varied between 2 0 and 7 1 mg/1 over the same period The concentrations of TPH as gasoline and diesel in well MW-2A have shown a steady decrease in 1992, and concentrations of both constituents have not been detected in MW-2A since December 1992 The occurrence of BTEX compounds in ground water has paralleled that of TPH Concentrations of BTEX compounds detected in MW-1A have fluctuated over time, while concentrations detected in MW-2A have steadily decreased over time and have been non-detect since December 1992 In April 1992, very low concentrations of BTEX (less than 0008 mg/1) were detected in MW-3A, but all concentrations have been non-detect since June 1992 The ground water data for Site #2 are shown in Table 3-2 3-6