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RESUSPENSION OF CONTAMINATED FIELD AND FORMULATED REFERENCE SEDIMENTS PART 1: EVALUATION OF METAL RELEASE UNDER CONTROLLED LABORATORY CONDITIONS
Citation:
CANTWELL, M. G., R. M. BURGESS, AND J. KING. RESUSPENSION OF CONTAMINATED FIELD AND FORMULATED REFERENCE SEDIMENTS PART 1: EVALUATION OF METAL RELEASE UNDER CONTROLLED LABORATORY CONDITIONS. CHEMOSPHERE. Elsevier Science Ltd, New York, NY, 73(10):1824-1832, (2008).
Impact/Purpose:
Determine the potential for metals to be release from sediments during resuspension events such as dredging.
Description:
In aquatic systems where metal-contaminated sediments are present, the potential exists for metals to be released to the water column when sediment resuspension occurs. The release and partitioning behavior of sediment-bound, toxic heavy metals is not well understood during resuspension events. In this study, metal release from sediments during resuspension was evaluated using a series of formulated reference sediments with known physical and chemical properties which were amended with heavy metals (i.e., Cd, Cu, Hg, Ni, Pb, Zn). Sediment treatments with varying quantities of acid volatile sulfide (AVS), total organic carbon (TOC), and different grain size distributions were resuspended under controlled laboratory conditions to evaluate their respective effects on dissolved metal concentrations. Overall, AVS had the greatest effect on limiting release of dissolved metals, followed by grain size and TOC. Models were developed to predict dissolved concentrations of Cd, Ni, Pb and Zn based on the formulated sediment AVS:metal molar ratios. Predictions were evaluated by comparison to measured dissolved metal concentrations in contaminated field sediments resuspended under identical conditions. Dissolved metal concentrations released from the resuspended field sediments were low overall, in most cases lower than predicted values. Overall, results indicate that for sulfidic sediments, very low levels of the study metals are released to the dissolved phase during short-term resuspension.