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�k <br /> i <br /> Evaluation Report (PIER) prepared by RESNA (RESNA, June 25, 1992, Report 30004-4) <br /> Site Geology <br /> Based on previous soil characterization sediments underlying the site appear to consist primanly <br /> of silt with some clay and silt with fine- to medium-grained sand The interpreted subsurface <br /> conditions are shown on geologic cross-section A-A' and section B-B' (figures 3 and 4, <br /> respectively) The trace of the geologic cross-sections is included on Plate 2 <br /> Vapor Extraction Test <br /> On March 3,1992, the previous consultant conducted a soil vapor extraction test (S VET) to <br /> evaluate the feasibility of using soil vapor extraction to remediate vadose-zone soil at the site <br /> Appendix A contains a copy of the previous consultant's SUET report <br /> The previous consultant utilized the vacuum and distance measurements obtained during the <br /> SVET to estimate an effective radius of influence for the site The previous consultant estimate <br /> that a wellhead flowrate of 80 cfm will result in an effective radius of influence of approximately <br /> 30 feet for one vapor-extraction well <br /> PRELIMINARY EVALUATICON OF REMEDIAL ALTERNATIVES <br /> Based on the size of the site, the extent and concentrations of the hydrocarbons in soil, the <br /> minima impact to groundwater, and the type of soil present at the site, in-situ bioremediation, <br /> chemical neutralization, and slung wall containment are not technically or economically feasible <br /> remedial options The following feasible options are presented <br /> Soil Remediation <br /> 1. Excavation <br /> Vadose soil with residual hydrocarbons occurs in the vicinity of the UST's and extends toward <br /> the southern dispenser island Capillary fringe soil is affected Excavation as a remedial <br /> alternative will require removal of the UST's. if this alternative is selected, soil removed by <br /> excavation can not be treated onsite due to lack of available space and site constraints, therefore, <br /> the soil must be hauled to an appropriate landfill for treatment and disposal Additionally, <br /> because petroleum hydrocarbons were detected in soil samples collected to groundwater <br /> (approximately 40 feet below surface grade) near the UST's, it is not feasible to excavate all <br /> petroleum hydrocarbons impacted due to excavation equipment limitations PP911YEO <br /> AUGG 0 9 1994 <br /> ENVIRONMENTAL HEALTH <br /> PERMIUSERVICES <br />