Laserfiche WebLink
. High MTBE and TBA concentrations are correlative with increased groundwater elevations <br /> beneath the site <br /> Seven cone penetrometer test (CPT) borings (CPT-1 through CPT-7) were advanced in <br /> September 2005, on behalf of Palisades and under the direction of Stratus personnel, to further <br /> characterize the geology beneath the site and the extent of petroleum hydrocarbon impact to soil <br /> Findings of this investigation suggest that subsurface MTBE and TBA impact extends to <br /> approximately 60 feet bgs in the eastern portion of the site The current monitoring well network <br /> does not allow for monitoring of dissolved petroleum hydrocarbon concentrations below <br /> approximately 27 feet bgs <br /> A 7-11 service station is situated at 2725 Country Club Boulevard, immediately west (generally <br /> upgradient) of the site (see Figure 3) Subsurface petroleum hydrocarbon impact has been <br /> reported in soil and groundwater beneath this property, and an environmental oversight case at <br /> this station is active Petroleum hydrocarbon impact observed at Exxon/Palisades well MW-7, <br /> and concentrations observed in samples collected from borings CPT-5 through CPT-7, appears to <br /> have originated from beneath the 7-11 property, given the historical groundwater flow direction <br /> in the site vicinity <br /> The purpose of this SCM is to integrate the hydrogeologic and chemical analytical data gathered <br /> to date to better understand the extent of petroleum hydrocarbon impact to soil and groundwater <br /> Pertinent information collected at other UST sites located in the site vicinity has also been <br /> incorporated into this model This SCM includes tables and figures that have been generated <br /> from previous site assessment activities, and the findings of recently completed site assessment <br /> activities The model identifies transport and exposure pathways, and data gaps that require <br /> further characterization, and provides a platform to communicate activity and progress <br /> Stratus recommends installation of additional monitoring wells to characterize the extent of <br /> petroleum hydrocarbon impact to shallow groundwater Stratus also recommends installation of <br /> monitoring wells to characterize the extent of impact in various permeable strata below shallow <br /> groundwater (first encountered water) <br /> K\USA GasolmeW835\Reportslusa835-scm assessment-report doc Page 2 5TRATU5 <br />