title: Uptake, distribution, depletion, and in ovo transfer of isomers of hexabromocyclododecane flame retardant in diet-exposed American kestrels (Falco sparverius).
abstract: Hexabromocyclododecane (HBCDD) is a flame retardant and a global contaminant, yet the toxicokinetics of HBCDD diastereoisomers remains unknown in wildlife species. The present study examined in captive American kestrels (Falco sparverius) (diastereo) isomer-specific HBCDD uptake, depletion, tissue distribution, and transfer to eggs in a dietary dosing study with an HBCDD technical mixture (HBCDD-TM). Adult tissue and plasma collections were from separate cohorts of unpaired individual males (n = 10) and females (n = 10) exposed for 21 d to 800 ng/g wet weight of HBCDD-TM (in safflower oil and injected into their cockerel [brain] diet), followed by a 25-d depuration period. A separate cohort of 12 males only was used for control adult tissue and plasma collections. For egg collections, separate cohorts of 11 control pairs (n = 22 birds) and 20 HBCDD-exposed pairs (n = 40 birds) were allowed to breed, and their eggs were collected (n = 19 exposed eggs and n = 10 control eggs). The sum (Σ) HBCDD concentrations were near or below detection (<0.01-0.1 ng/g wet wt) in all control samples but quantifiable in all samples from exposed birds (no differences [p > 0.05] between males and females). Arithmetic mean ΣHBCDD concentrations were highest in fat >> eggs > liver > plasma. The mean ΣHBCDD depletion rate in plasma between the uptake and depuration periods was estimated to be 0.22 ng/g/d with a half-life of approximately 15 d. The γ-HBCDD diastereoisomer was >60% of the ΣHBCDD in plasma after the uptake period and similar to the HBCDD-TM (∼80%). After the depuration period, α-HBCDD was >70% of the HBCDD in plasma, fat, liver, and eggs; and this α-HBCDD domination indicated isomer-specific accumulation as a result of selective metabolism, uptake, protein binding, and/or in ovo transport.
authors.affiliation: National Wildlife Research Centre, Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Science Directorate, Environment Canada, Carleton University, Ottawa, Ontario, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Mattioli
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Marteinson
authors.forename: David
authors.initials: D
authors.lastname: Bird
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Ritchie
authors.forename: Kim J
authors.initials: KJ
authors.lastname: Fernie
mesh_terms: D000818:Animals; D001835:Body Weight; D004032:Diet; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000378:metabolism; D046093:Falconiformes / Q000378:metabolism*; D005223:Fats / Q000737:chemistry / Q000378:metabolism; D005260:Female; D005411:Flame Retardants / Q000032:analysis / Q000378:metabolism*; D006207:Half-Life; D006842:Hydrocarbons, Brominated / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D007536:Isomerism; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D010063:Ovum / Q000737:chemistry* / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D004785:Environmental Pollutants; D005223:Fats; D005411:Flame Retardants; D006842:Hydrocarbons, Brominated; C089796:hexabromocyclododecane
keywords: American kestrel; Diet-exposed; Flame retardant; Hexabromocyclododecane diastereoisomer; Uptake and distribution