Management of Pcb-contaminated Sediments through Sediment Characterization and Evaluation of Active Capping Techniques

Polychlorinated biphenyls (PCBs) were heavily used for over fifty years in industrial applications, primarily inside capacitors and transformers. Over twenty years after their phase-out in the United States PCBs are still one of the most widespread contaminants in the environment. PCBs are stable compounds with low aqueous solubility and vapor pressure. These unique properties led to the extensive use of PCBs and are also responsible for their continued presence in the environment today. Due to their hydrophobic nature PCBs tend to accumulate in soils and sediments, and also bioaccumulate in the fatty tissues of aquatic organisms. At higher levels of the food chain, biomagnification produces elevated PCB concentrations in tissue due to the transfer of PCBs from smaller organisms consumed by the larger organisms. Several locations across the United States have fish consumption advisories in place due to PCB contamination. Currently used management techniques include monitored natural recovery, insitu capping, and dredging and dewatering. All of these methods have major drawbacks preventing their wide-scale use. Monitored natural recovery is subject to a large degree of uncertainty and is also viewed negatively by the public. In-situ capping is prone to disruption and caps are difficult to install at a controlled thickness. Dredging and dewatering is the most commonly used process because it physically removes