Laserfiche WebLink
1 <br /> ProjectNo 58100-06-IIB <br /> April 19, 1996 <br /> 6.0 DATA EVALUATION AND DISCUSSION <br /> 61 Petroleum Hydrocarbons In Soil <br /> ' The distribution of detected petroleum hydrocarbons in soil is primarily limited to vadose zone soil <br /> beneath the former USTs with the soil plume bounded by borings SB-1, SB-2, MW-1, MW-2, MW-3, <br /> ' and VW-I <br /> The vadose zone soil plume bounded by SB-1, SB-2, MW-1, MW-2, MW-3 and VW-1 has an <br /> t approximate volume of 1,500 cubic yards However, because the exact location of the central portion <br /> of the soil plume has not been identified, the maximum concentration of impacted soil and the exy�ting <br /> mass of TPHg cannot be estimated On the basis that the central portion of the vadose zone plume is <br /> located between borings VW-I and VW-2,the assumed plume boundaries are approximated on Figure <br /> 3, Cross Section A-A' <br /> 62 Dissolved Petroleum Hydrocarbons In Groundwater <br /> Evaluation of groundwater quality data collected from the onsite monitoring wells indicates that the <br /> former refueling operations has impacted the groundwater The highest TPHg and benzene <br /> concentrations were detected within and to the vicinity of the former UST excavation (VW-1 and <br /> VW-1) at maximum concentrations of 16,000 ug/L TPHg and 3,000 ug/L benzene The highest <br /> MTBE concentration of 170 ug/L was detected in the eastern most perimeter well MW-11, which is <br /> the farthest well from the source area <br /> ' Concentrations of TPHg decreased to below test method detection limits and are currently bounded to <br /> the north and south by perimeter wells MW-9, MW-10, and MW-12 TPHg, benzene, and MTBE <br /> were detected in the eastern most perimeter well MW-1 1, consequently, the lateral limits of TPHg, <br /> ' benzene,and MTBE beyond MW-11 has not been established <br /> 1 <br /> 11 <br />