title: The flame retardant β-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane: fate, fertility, and reproductive success in American kestrels (Falco sparverius).
abstract: Captive American kestrels (Falco sparverius) were exposed via diet during reproduction to an environmentally relevant concentration of β-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (β-TBECH). The β-TBECH isomer was injected into the food source at a daily dosing concentration of 0.239 ng/g kestrel/day (22 pairs); control birds were exposed via diet to the safflower oil vehicle only (24 pairs). Eight pairs in each group were exposed for four weeks and sacrificed for tissue analysis; the remaining pairs completed their breeding cycle, with exposure ceasing at the end of incubation (82 days). α- and β-TBECH appeared to be rapidly metabolized and/or eliminated from fat, liver, and plasma; both isomers and potential hydroxylated metabolites of β-TBECH (plasma) were undetected. Notwithstanding, compared to controls, pairs exposed to β-TBECH laid fewer eggs (p = 0.019) and laid lighter eggs (successful eggs: p = 0.009). Exposed pairs also demonstrated poorer egg fertility (p = 0.035) although testis mass and histology were similar among males. Reductions in egg production and fertility resulted in decreased hatchling success (p = 0.023). The β-TBECH-exposed pairs also produced fewer males overall (p = 0.009), which occurred concurrently with increased estradiols maternally deposited in eggs (p = 0.039). These findings demonstrate that β-TBECH may be detrimental for breeding in wild birds receiving similar exposure levels.
authors: Ecotoxicology & Wildlife Health Division, Science & Technology Branch, Environment Canada, Burlington, Ontario, Canada.
authors: Sarah C
authors: SC
authors: Marteinson
authors: Robert J
authors: RJ
authors: Letcher
authors: Laura
authors: L
authors: Graham
authors: Sarah
authors: S
authors: Kimmins
authors: Gregg
authors: G
authors: Tomy
authors: Vince P
authors: VP
authors: Palace
authors: Ian J
authors: IJ
authors: Ritchie
authors: Lewis T
authors: LT
authors: Gauthier
authors: David M
authors: DM
authors: Bird
authors: Kim J
authors: KJ
authors: Fernie
mesh_terms: D000818:Animals; D003510:Cyclohexanes / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005411:Flame Retardants / Q000378:metabolism / Q000633:toxicity*; D008297:Male; D020304:Raptors / Q000378:metabolism / Q000502:physiology*; D012098:Reproduction / Q000187:drug effects*
chemical_list: D003510:Cyclohexanes; D005411:Flame Retardants; C517232:1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane