SS4.03 Factors Controlling the Bioavailability and Bioaccumulation of Inorganic and Organic Chemicals into Aquatic Food Chains
Date: Friday, June 14, 2002
Time: 8:30:00 AM
Location: Carson B
 
TwiningBS, Marine Sciences Research Center, Stony Brook University, Stony Brook, NY, USA, btwining@ic.sunysb.edu
Twiss, M, R, Department of Chemistry, Biology, and Chemical Engineering, Ryerson Polytechnic University, Toronto, ON, Canada, m2twiss@acs.ryerson.ca
Fisher, N, S, Marine Sciences Research Center, Stony Brook University, Stony Brook, NY, USA, nfisher@notes.cc.sunysb.edu
 
BIOACCUMULATION, REDOX CYCLING, AND TROPHIC TRANSFER OF THALLIUM BY GREAT LAKES PLANKTON COMMUNITIES
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The redox metal thallium has been identified by the US EPA as a priority pollutant metal, yet little is known about its interaction with plankton communities in aquatic systems. We conducted lab and field experiments with Tl to investigate the bioaccumulation of both the inorganic and methylated (dimethyl thallium—DMT) forms of this metal by freshwater plankton in the Great Lakes. Tl(I) and DMT were only weakly scavenged (<5% accumulation onto particles) by plankton assemblages sampled from Lakes Erie and Ontario. Lab studies with phytoplankton revealed both Tl(I) and DMT uptake to be metabolically-controlled, and Tl(I)—but not DMT—uptake was also strongly influenced by K, suggesting that accumulation may be via a K uptake pathway. Additionally, plankton appear to mediate the redox cycling of Tl, as incubations with natural plankton (<210 um) resulted in conversion of Tl(I) to Tl(III) (74% after 2.5 days) while no conversion was observed in treatments with sterile-filtered lake water. We are also measuring the trophic transfer of Tl from algae and heterotrophic flagellates to crustacean zooplankton and will present these results.