T9 AM Bioaccumulation and Biomagnification
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in 339-340
(HEL-1117-832130) Occurrence and biomagnification of polychlorinated naphthalenes and dioxin-like PCBs in a Lake Ontario food web.
Helm, P.1, Whittle, D.2, Tomy, G.3, Fisk, A.4, Marvin, C.5, 1 Ontario Ministry of the Environment, Toronto, Ontario, Canada2 Fisheries and Oceans Canada, Burlington, Ontario, Canada3 Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada4 University of Georgia, Athens, Georgia, United States5 Environment Canada, Burlington, Ontario, Canada
ABSTRACT- Fish and invertebrates collected in 2002/2003 and sediments collected in 1998 from Lake Ontario were analyzed for polychlorinated naphthalenes (PCNs) and dioxin-like polychlorinated biphenyls (DL-PCBs). The species analyzed included lake trout, alewife, rainbow smelt, slimy sculpin, Mysis relicta, Diporeia hori, and net plankton. Mean 
PCN concentrations (tri- to octaCN; wet weight [ww]) ranged from 14 +/- 9 pg/g in plankton to 3500 +/- 3200 pg/g in lake trout, which are about 10 times higher than in lake trout from Lake Superior. Biomagnification was examined as a function of trophic position, determined through stable nitrogen isotopes, and through predator-prey biomagnification factors (BMFs). A positive relationship was found between trophic level and lipid-adjusted concentrations (lw), demonstrating PCN biomagnification in this food web. Trophic magnification factors (TMFs) determined from this relationship ranged from 2.4 to 6.9 for the most bioaccumulative PCNs, and was 3.1 for PCN. A similar range in TMF values was found for the DL-PCBs. BMFs for lake trout/diet-weighted prey (90% alewife; 7% rainbow smelt; 2% slimy sculpin) were similar for the penta- & hexaCNs and DL-PCBs. PCNs contributed from 12-22% of dioxin toxic equivalents (TEQ) relative to DL-PCBs in lake trout. Sediment concentrations ranged from 21-38 ng/g dry weight (tri-octaCNs) with a homolog pattern resembling those found in sediments known to be contaminated from chlor-alkali production.
Key words: PCNs, TEQ, TMF, BMF