SS4.03 Factors Controlling the Bioavailability and Bioaccumulation of Inorganic and Organic Chemicals into Aquatic Food Chains
Date: Friday, June 14, 2002
Time: 10:45:00 AM
Location: Carson B
 
MillerCL, Chesapeake Biological Laboratory, University of Maryland Center of Environmental Sciences, Solomons, USA, cmiller@cbl.umces.edu
Heyes, A, , Chesapeake Biological Laboratory, University of Maryland Center of Environmental Sciences, Solomons, USA, heyes@cbl.umces.edu
Mason, R, P, Chesapeake Biological Laboratory, University of Maryland Center of Environmental Sciences, Solomons, USA, mason@cbl.umces.edu
 
The Role of Tidal Resuspension on Mercury dynamics at the Sediment-Water Interface in the Lower Hudson River
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It has been suggested that tidal resuspension of sediment in estuaries is a means of transporting mercury (Hg) and methylmercury (MeHg) seaward, both within the particulate load and by desorption into the “dissolved” phase. We examined Hg and MeHg mobility in the lower portion of the Hudson River Estuary. Average sediment Hg and MeHg concentrations were 1 ug g-1 and 1.5 ng g-1, respectively. During tidal resuspension events, suspended solid concentrations 1.5m above the bottom peaked at 500 mg L-1. Particle Hg and MeHg concentrations ranged from 215 to 740 ng g-1 and 0.5 to 2.5 ng g-1, respectively. Sequential extractions revealed the reactive fraction (iron oxides and iron sulfides) dominated the Hg solid phase speciation on water column particles and the speciation did not change during a single tidal resuspension. However, changes in Hg partitioning within sedimentary particles occurred over months with Hg predominantly binding to the organic fraction in October 2001 and the reactive fraction in June 2001. We propose repartitioning of Hg on short time scales is not an important transport mechanism.