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PHYSICAL, CHEMICAL AND BIOLOGICAL TOOLS FOR EVALUATING, MONITORED NATURAL RECOVERY OF PCB CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC
Citation:
Mills*, M A., J M. Lazorchak, J SchubauerBerigan, D M. Walters, P T. McCauley*, T. Lyons,T.M., P dePercin*, D L. Lattier, E Kleiner*, H. K. Howard*, Zeller*, V. S. Magar, J. E. Abbott, AND Foote. PHYSICAL, CHEMICAL AND BIOLOGICAL TOOLS FOR EVALUATING, MONITORED NATURAL RECOVERY OF PCB CONTAMINATED SEDIMENTS IN LAKE HARTWELL, CLEMSON, SC. Presented at Florida International University, Miami, FL, 11/25/03.
Description:
Management of contaminated sediments poses significant challenges due to varied contaminants and volumes of sediments to
manage. Dredging, capping, and monitored natural recovery (MNR) are the primary approaches for managing the contaminated sediment risks.
Understanding how effectively these approaches manage risk in different environments is critical for choosing appropriate remedies to predictably reduce risk to human and ecological receptors. MNR is a risk management option that relies on natural environmental processes to permanently reduce risk, and includes careful assessment, modeling, and monitoring to ensure success.
To investigate the physical, chemical, and biological processes associated with MNR of contaminated sediments, a site where MNR of contaminated sediments, a site where MNR was the remedy was chosen (Sangamo-Weston/Twelvemile Creek/Lake Hartwell Superfund Site, near Clemson, SC). A collaborative project, involving multiple USEPA ORD Laboratories, USEPA Region 4, and contractor support (Battelle Memorial Institute), was established to address multiple issues involved at Lake Hartwell.
To evaluate the physical, chemical, and biological processes and how these processes relate to the risk, a mechanistic understanding of these processes is needed. Empirical relationships are not sufficient to allow extrapolation to additional sites, contaminants, or remedial actions. To examine these processes, a mass balance approach was taken at Lake Hartwell. Site characterization and monitoring have been conducted at the site for three years to evaluate effective tools for characterizing the risk from the contaminants. As a synposis:
>- Year 2000 - Chemical (PCB) characterization and age dating of deep sediment cores in 5-cm increments at 10 stations along centerline of upper
Lake Hartwell and most of its northern tributaries.
>- Year 2001 - Chemical (PCB) characterization and age dating of deep sediment cores in 5-cm increments at three stations across Lake Hartwell
(bank to bank) plus chemical (PCB) characterization of overlying water column and atmosphere at air-water interface.
>- Year 2002 - Development and evaluation of biological and surrogate monitoring tools to assess recovery of entire Lake Hartwell ecosystem
including indigenous fish, clams, plankton, and macroinvertebrates; evaluation of physical chemical transport mechanisms for PCBs from the sediment to the water column' additional sediment, water, and air monitoring.
>- Year 2004 (Planned) - Extension of physical, chemical, and biological processes database on a seasonal sampling regime to provide more refined model inputs (Mechanistic and data): optimize monitoring and assessment tools for use at other contaminated sites.