Bioconcentration of inorganic and organic thallium by freshwater phytoplankton

Authors

  • Michael R. Twiss,

    Corresponding author
    1. Department of Chemistry, Biology and Chemical Engineering, Ryerson Polytechnic University, 350 Victoria Street, Toronto, Ontario, Canada, M5B 2K3
    • Department of Biology/Clarkson Center for the Environment, Clarkson University, Potsdam, NY 13699-5805, USA
    Search for more papers by this author
  • Benjamin S. Twining,

    1. Marine Sciences Research Center Stony Brook University Stony Brook New York USA 11794-5000
    Search for more papers by this author
  • Nicholas S. Fisher

    1. Marine Sciences Research Center Stony Brook University Stony Brook New York USA 11794-5000
    Search for more papers by this author

Abstract

Uptake of inorganic Tl(I) and dimethylthallium, (CH3)2Tl+, by Chlorella spp. (Chlorophyta) and the diatom Stephan-odiscus hantzschii (Heterokontophyta) were measured using radio-tracer techniques in water from Lakes Erie and Superior (North America). Uptake of both Tl(I) and dimethylthallium was bioactive. Uptake of [204Tl]-Tl(I) was greater in Lake Superior water than in Lake Erie water due to the greater K content in Lake Erie that inhibits Tl(I) uptake by phytoplankton but not that of [204Tl]-dimethylthallium. Volume-based bioconcentration factors for Tl(I) after 72 h of exposure were 5 × 104 and 1.1 × 104 for Chlorella sp. and S. hantzschii; for dimethylthallium they were 7.8 × 102 and 8.3 × 103. Both Tl(I) and Tl(III) were concentrated similarly by Chlorella spp. These results suggest that chlorophytes, but not diatoms, accumulate Tl(I) to a greater extent than dimethylthallium. Greater bioaccumulation factors of inorganic Tl are possible in waters containing low amounts of K+; water quality guidelines seeking to protect biota from deleterious effects of Tl should consider the role of K.

Ancillary