Laserfiche WebLink
Binayak Acharya Project 2074-001.01 <br /> May 18, 1995 <br /> Page 5 <br /> Groundwater Monitoring <br /> In this alternative, semiannual groundwater monitoring would be performed on well MW-1 <br /> for one year. The samples would be analyzed for TPH by USEPA method 8015M and for <br /> VOCs by USEPA method 8240. <br /> The depth to first-encountered groundwater at the Site is approximately 72 feet <br /> (22 meters) BGS and the bottom of the petroleum-hydrocarbon-impacted soil is estimated <br /> at 14 feet (4 meters) BGS. This leaves approximately 59 feet (18 meters) of soil between <br /> the source and the water table. The stratigraphy underlying the Site consists of clayey, <br /> silty, and gravely sands. Based on the infiltration modeling presented in Appendix A, it will <br /> take more than 20,000 years for the source to impact the groundwater. Based on this, a <br /> groundwater monitoring program over the next year or even several years is not a realistic <br /> option. <br /> Soil Excavation <br /> In this alternative soil would be excavated and either treated or disposed of at an off-site <br /> facility. As a conservative estimate, the 10-square-meter (33 feet) value from the model is <br /> assumed for the lateral extent of the impacted soil. The vertical extent of the impacted soil <br /> is conservatively estimated between the depths of 3 and 4 meters (11 to 14 feet) BGS. <br /> With these assumptions, the total volume of soil to be excavated would be approximately <br /> 40 cubic meters or 52 cubic yards. Approximately 13 cubic yards of this would have to be <br /> treated or hauled off site for >sposal. The remaining 39 cubic yards of soil would be <br /> backfilled into the excavation along with some imported fill material. The cost of such an <br /> excavation and treatment or disposal would be prohibitively high. EMCON does not <br /> believe that moving the waste to another location for treatment or disposal is a better <br /> alternative than leaving the soil in place, on site. <br /> RECOMMENDATIONS <br /> Based on the results of the model and the discussion of other alternatives, EMCON <br /> recommends no further action for the Site. This recommendation is based on the fact that <br /> the soil excavation alternative would be prohibitively expensive and would only serve to <br /> move the impacted soil to another location (landfill). The groundwater monitoring <br /> alternative will not yield any conclusive results because of the extended length of time it <br /> would take for the source to reach the groundwater. Therefore, no action is the <br /> appropriate alternative for this site. <br /> J:1SECTNPJ2120740010.1 B R-95Ujt:2 <br />