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Preliminary investigation of processes that affect source term identification

Description: Solid Waste Storage Area (SWSA) 5 is known to be a significant source of contaminants, especially tritium ({sup 3}H), to the White Oak Creek (WOC) watershed. For example, Solomon et al. (1991) estimated the total {sup 3}H discharge in Melton Branch (most of which originates in SWSA 5) for the 1988 water year to be 1210 Ci. A critical issue for making decisions concerning remedial actions at SWSA 5 is knowing whether the annual contaminant discharge is increasing or decreasing. Because (1) the magnitude of the annual contaminant discharge is highly correlated to the amount of annual precipitation (Solomon et al., 1991) and (2) a significant lag may exist between the time of peak contaminant release from primary sources (i.e., waste trenches) and the time of peak discharge into streams, short-term stream monitoring by itself is not sufficient for predicting future contaminant discharges. In this study we use {sup 3}H to examine the link between contaminant release from primary waste sources and contaminant discharge into streams. By understanding and quantifying subsurface transport processes, realistic predictions of future contaminant discharge, along with an evaluation of the effectiveness of remedial action alternatives, will be possible. The objectives of this study are (1) to characterize the subsurface movement of contaminants (primarily {sup 3}H) with an emphasis on the effects of matrix diffusion; (2) to determine the relative strength of primary vs secondary sources; and (3) to establish a methodology capable of determining whether the {sup 3}H discharge from SWSA 5 to streams is increasing or decreasing.
Date: September 1, 1991
Creator: Wickliff, D.S.; Solomon, D.K. & Farrow, N.D.
Partner: UNT Libraries Government Documents Department

Investigation of groundwater flow zones and contaminant transport in Solid Waste Storage Area 5 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

Description: An understanding of subsurface transport processes is essential to produce realistic predictions of future contaminant discharge from Solid Waste Storage Areas (SWSAs) at Oak Ridge National Laboratory (ORNL). Locating groundwater flow zones (permeable pathways) and determining the relative contributions of primary vs secondary contaminant sources are critical to the proper selection and evaluation of remedial actions. Because groundwater discharge from SWSA 5 contributes significant amounts of [sup 3]H and [sup 90]Sr to the White Oak Creek watershed, an area on the southeastern edge of SWSA 5 was chosen for an investigation aimed at understanding and characterizing the subsurface movement of contaminants. Preliminary data collected in 1991 indicated that the vertical distribution of [sup 3]H (0.02 to 279 [mu]Ci/L) observed over the sampled interval (O to 10 ft deep) may be a result of upward diffusion from a hydraulically dominant fracture (or fractured zone) below the sampled interval. The investigation continued this year (1992) with the primary objective of defining where the most permeable zones exist in the subsurface and how they relate to the vertical extent of [sup 3]H. An open borehole was drilled on the southeastern edge of SWSA 5 through the upper zones of soil and saprolite and then through interbedded shales and limestones to a depth of about 26 ft. Two methods were used to determine permeable zones within the borehole. In addition, samples were collected monthly from a nearby well and seep (where tritiated groundwater discharges) to determine seasonal variability in the transport of [sup 3]H and [sup 90]Sr from the study area.
Date: September 1, 1992
Creator: Hicks, D.S.; Solomon, D.K. & Farrow, N.D.
Partner: UNT Libraries Government Documents Department

The new definitive map of White Oak Lake

Description: A map of White Oak Lake was drawn from points on the shoreline established with the use of an electronic distance-measuring theodolite and a hand-held reflecting prism. Average water depths were determined along six transects. A planimeter was used to estimate the area of each section. The volume of each section was determined by multiplying the surface area by the average depth. The total area and volume of White Oak Lake were estimated to be 6.88 ha (17.0 acres) and 43,893 m{sup 3}(1,546,330 ft{sup 3}), respectively. The lake's surface area has been reduced at an average rate of 0.7% per year, and its volume has been reduced at an average rate of 1.1% per year. The volume of the lake can be reliably estimated only from current depth measurements throughout the lake, not from stage heights at the dam. The lake should be remapped periodically, and an estimate of the sediment volume should be made. 6 refs., 3 figs., 1 tab.
Date: October 1, 1991
Creator: Cox, D.K.; Farrow, N.D.; Kyker, W.C.; Faulkner, M.A. & Stubbs, L.M.
Partner: UNT Libraries Government Documents Department

Factors Controlling In Situ Uranium and Technetium Bioreductionat the NABIR Field Research Center

Description: This research hypotheses is: (1) Indigenous microorganisms in the shallow aquifer at the FRC have the capability to reduce U(VI) and Tc(VII) but rates are limited by--Scarce electron donor, Low pH and potentially toxic metals, and High nitrate. (2) U(VI) and Tc(VII) reduction rates can be increased by--Successive donor additions, Raising pH to precipitate toxic metals, and Adding humics to complex toxic metals and serve as electron shuttles.
Date: March 17, 2004
Creator: Istok, J.; Jones, J.; Park, M.; Sapp, M.; Selko, E.; Laughman, R. et al.
Partner: UNT Libraries Government Documents Department