title: Dietary exposure of American kestrels (Falco sparverius) to decabromodiphenyl ether (BDE-209) flame retardant: uptake, distribution, debromination and cytochrome P450 enzyme induction.
abstract: Accumulation and evidence of debromination of the flame retardant 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) have been reported for biota, including raptorial birds, based on PBDE congener residues in tissues and eggs. However, in vivo studies with BDE-209-exposed birds are rare and unknown for a raptorial species. In the present study, males (n=22) of raptorial American kestrels (Falco sparverius) were exposed to 116,000ng of BDE-209 (high purity, >98%; in safflower oil) per day for 21days (~2,436,000ng total BDE-209 exposure over this uptake period), followed by a 25-day depuration period. Control males (n=11) received the safflower vehicle only. In the exposed birds, BDE-209 was quantifiable in all plasma (end of uptake and depuration period) as well as liver and fat (end of depuration only) samples. The mean (±SE) BDE-209 level in plasma was 1474±1145ng/g wet weight (ww) at the end of the uptake period, and was significantly (p<0.001) lower (88%) at 174±148ng/g ww after the 25day depuration period. This equates to a mean reduction rate of 52ng/g ww per day and a rough estimation of the BDE-209 half-life in plasma of approximately 14days. The mean (±SE) BDE-209 levels were 4668±6192ng/g ww in the fat, and 338±311ng/g ww in the liver, of exposed individuals, which were significantly (p≤0.001) greater than mean concentrations (25±20 in fat and 2.6±0.9ng/g ww in liver) in the control birds. In addition to BDE-209, lower brominated PBDE congeners, and mainly meta- and para-debromination products of BDE-209 were also quantified in plasma, liver and/or fat. We estimated based on the dose that at least 80% of the non-BDE-209 concentration in the kestrel tissues and plasma must be derived from BDE-209 debromination by the kestrels. Where quantifiable, lower brominated PBDE concentrations were significantly (0.023>p>0.001) higher in the exposed relative to the control bird samples (except for BDE-154 and -153 in fat). Additional PBDE congeners found in plasma included nona-BDEs (208, 207 and 206), followed by octa-BDEs (197, 196, 201 and 203), and in liver and/or fat, the hepta-BDEs 180 and 183 and BDE-153. Higher hepatic EROD activity (cytochrome P450 1A1 monooxygenase-mediation) in the exposed birds compared to control birds was strongly suggested to be PBDE-induced, and was consistent with BDE-209 and congener metabolism in the exposed kestrels. The mean EROD activity rate was 36.1pmol/min/mg protein relative to the (n=4) control birds whose activity was just above the detection limit (10.3pmol/min/mg protein). Overall, the results demonstrated that following diet exposure of kestrels to high purity BDE-209, uptake occurred as well as BDE-209 degradation via debromination to lower brominated PBDE congeners.
authors: Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, Ottawa, Ontario K1A 0H3, Canada. Electronic address: robert.letcher@ec.gc.ca.
authors: Robert J
authors: RJ
authors: Letcher
authors: Avian Science and Conservation Centre, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.
authors: Sarah C
authors: SC
authors: Marteinson
authors: Avian Science and Conservation Centre, Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada; Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment Canada, Burlington, Ontario, Canada.
authors: Kim J
authors: KJ
authors: Fernie
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004032:Diet; D004781:Environmental Exposure; D004790:Enzyme Induction; D046093:Falconiformes / Q000378:metabolism*; D005411:Flame Retardants / Q000378:metabolism*; D006207:Half-Life; D055768:Halogenated Diphenyl Ethers / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D011075:Polybrominated Biphenyls / Q000378:metabolism*; D014481:United States
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D011075:Polybrominated Biphenyls; C517828:hexabrominated diphenyl ether 153; D003577:Cytochrome P-450 Enzyme System; C533761:hexabromodiphenyl ether 154; C010902:decabromobiphenyl ether
keywords: Accumulation; American kestrel; Debromination; Decabromodiphenyl ether (BDE-209); Enzyme activity; Polybrominated diphenyl ether (PBDE)