Analysis of proposed postclosure alternatives for the Bear Creek Burial Grounds at the Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

摘要

The Bear Creek Burial Grounds are located in Bear Creek Valley about 2 miles southwest of the Y-12 Plant on the United States Department of Energy (DOE) Oak Ridge Reservation. From 1955 until recently solid and liquid wastes from the Y-12 plant were deposited in Burial Grounds waste disposal areas. The principal types of wastes disposed of were solvents, oils, coolants, uranium, and other heavy metals. Methods of disposal included filling excavated trenches with solid wastes and pouring liquid wastes onto the filled trenches or into standpipes embedded in the trenches. Since 1982 the Y-12 Plant has sampled groundwater, surface water, soils, and sediments in Bear Creek Valley for contamination. At the Burial Grounds site, groundwater is the most seriously contaminated medium: very high levels of several volatile organic compounds (VOCs) occur near the eastern trenches. In addition, elevated levels of VOCS, metals, and polychlorinated biphenyls (PCBS) have been found in soils in the immediate vicinity of the waste trenches and the Oil Retention Ponds and in sediments. This report the risks to human health and the environment posed by the Bear Creek Burial Grounds under three remedial alternatives proposed under the CAPCA project: take noaction; place an impermeable cap over the Burial Grounds trenches, and construct subsurface drains to reduce leachate production; and in addition to capping the site, construct a network of recovery wells to extract contaminated groundwater for treatment in an air-stripping facility. Two recovery well options were evaluated: (a) recovery of contaminants in only the upper 200 ft of aquifer and (b) recovery of contaminants over 600 ft of aquifer.