M12 PM Remediation
Monday, 14 November 2005: 1:50 PM - 5:30 PM in 345-346

(CAL-1117-826480) Optimization of PCB Dechlorination by Palladized Magnesium in Marine Sediments: The role of solvents in dechlorination.

Calante, I¹, Gardner, K², Spear, J³, Hadnagy, E⁴, ¹ University of New Hampshire, Durham, NH, USA² University of New Hampshire, Durham, NH, USA³ University of New Hampshire, Durham, NH, USA⁴ University of New Hampshire, Durham, NH, USA

ABSTRACT- Currently, marine sediments contaminated with Polychlorinated Biphenyls (PCBs) are treated ex-situ through dredging followed by landfill. This form of treatment can be very costly, has high impacts on the marine environment, and can further disturb and disperse PCBs from the sediments. Capping and monitored natural recovery are two other viable options, both of which suffer from leaving contamination in place. This research focuses on the optimization of in-situ treatment of marine sediments contaminated with PCBs by dechlorination with palladized magnesium. Three sediments (New Bedford Harbor, MA, Housatonic River, MA, and Hudson River, NY) have been tested for dechlorination with palladized magnesium (4 mm magnesium particles coated with 0.1% by weight palladium). High PCB removals were observed for sandy sediments with low organic carbon content, whereas lower removals where seen for sediments with higher organic carbon content. Desorption experiments using Tenax beads were conducted to see whether PCB desorption from sediment was a rate limiting step for dechlorination. Sediment characteristics such as PCB concentration and organic carbon content are being used to optimize the percent addition of palladized magnesium to each sediment. In addition, biodegradable solvents are being used to extract PCBs from the sediment and make them available to react with the palladized magnesium. The results from these studies will be presented.

Key words: PCB, Magnesium palladium, dechlorination, solvents