PARENT SESSION

MA9 Emerging Contaminants/Receptors
Room 12A/B, Level 4
8:00 AM - 12:00 PM, Monday, 10 November 2003
Chair: Gaylor, Michael ,

(085) Biomagnification of - and -hexabromocyclododecane congeners in a Lake Ontario food web.

Tomy, G¹, Budakowski, W¹, Halldorson, T¹, Whittle, M², Keir, M², Alaee, M³, ¹ Department of Fisheries and Oceans, Winnipeg, Manitoba, Canada² Department of Fisheries and Oceans, Burlington, Ontario, Canada³ Environment Canada, Burlington, Ontario, Canada

ABSTRACT- Hexabromocyclododecane (HBCDD) belongs to the class of cycloaliphatic brominated flame retardants (BFRs) used primarily in the building industry as a thermal insulator additive in polystyrene foam. Secondary uses are in upholstery textiles. The HBCDD technical mixture contains three diastereoisomers (, , ) existing in proportions of approximately 6, 8 and 80%, respectively, together with other lower brominated impurities. This study examined the biomagnification of HBCDD congeners in a Lake Ontario food web. – and –HBCDD were detected in all trophic levels of the food web. The –isomer was below method detection limits. The remarkable feature of the ion chromatograms was that the –HBCDD, which is the dominant isomer in the technical mixture, is much less abundant in the samples than the –isomer. The ratio of the – to –isomer (based on their areas) in the technical standard is 13, whereas in the samples the – to –isomer ratio ranges from 0.12 for alewife to 0.47 for Diporeia. Whole body concentrations (ng/g, wet wt) of – and –HBCDD were highest in the lake trout ranging from 1.2–5.9 ng/g (wet wt) for the –isomer and 0.2–1.2 ng/g for the –isomer. For the forage fish, the trends in – and –HBCDD levels were slimy sculpin > smelt > alewife. No real differences in biomagnification factors (BMFs) were observed between the isomers. The highest BMF was observed between lake trout:alewife (–:8.9 and –:12.4).

Key words: biomagnification, Hexabromocyclododecane, transformation, food web