PARENT SESSION
PW7 - Biotransformation / Metabolisms / Degradation
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P789) Dietary PBDE Exposure and Phenolic Metabolites in Juvenile Lake Trout (Salvelinus namaycush) .
Letcher, Robert*,1, Li, Juliana1, Halldorson, Thor2, Braekevelt, Eric2, Danell, Robert2, Palace, Vince2, Wautier, Kerry2, Fisk, Aaron3, Tomy, Gregg2, 1 Great Lakes Institute, University of Windsor, Windsor, Ontario, Canada2 Dept. of Fisheries and Oceans, Freshwater Institute, Winnipeg, Manitoba, Canada3 Warnell School of Forest Resources, University of Georgia, Athens, Georgia, U.S.A.
ABSTRACT- Polybrominated diphenyl ethers (PBDEs) are a significant class of contaminant in lake trout (Salvelinus namaycush) from the Laurentian Great Lakes, where total PBDE concentrations in whole fish homogenates have been reported to range from 117 to 434 part-per-billion (lipid weight). Hydroxylated PBDEs (OH-PBDEs) have been detected in free-ranging herring and salmon, and in pike exposed to a diet containing radiolabeled 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47). Metabolism of PBDEs in exposed fish is therefore a plausible toxicokinetic process affecting the fate and potential toxicity of this class of flame retardants. The present study investigated OH-PBDE metabolite formation and kinetics in vivo in juvenile lake trout exposed through the diet to 13 PBDE congeners (3-10 Br atoms), which included the major persistent PBDE congeners BDE-47, BDE-99 (2,2',4,4',5-pentabrominated diphenyl ether) and BDE-100 (2,2',4,4',6-pentabrominated diphenyl ether). Over a 56 uptake period, lake trout were fed a daily regime of PBDEs with each congener concentration at 25 ng/g (high), 2.5 ng/g (low) and 0 ng/g (control). At day 56, dietary PBDE exposure was terminated, and plasma samples were collected on days 7, 14, 28, 56 and 112 of the clearance phase. At each of these time points, the plasma was analyzed for PBDEs and OH-PBDEs to qualitatively and quantitatively assess PBDE elimination in relation to OH-PBDE formation and elimination. The exposed lake trout demonstrated OH-PBDE formation as well as PBDE elimination. The present study provides vital information on the role of metabolism in the toxicokinetics and fate of PBDEs in lake trout.
Key words: lake trout, polybrominated diphenyl ethers, metabolism, in vivo