Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, Pacific Wildlife Research Centre, Delta, British Columbia, Canada.
U. S. Geological Survey, Patuxent Wildlife Research Center, Beltsville, MD, USA.
Ecotoxicol Environ Saf. 2019 Sep 15;179:151-159. doi: 10.1016/j.ecoenv.2019.04.047. Epub 2019 Apr 28.
Tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTPBE) are both brominated flame retardants (BFRs) that have been detected in birds; however, their potential biological effects are largely unknown. We assessed the effects of embryonic exposure to TBBPA-BDBPE and BTBPE in a model avian predator, the American kestrel (Falco sparverius). Fertile eggs from a captive population of kestrels were injected on embryonic day 5 (ED5) with a vehicle control or one of three doses within the range of concentrations that have been detected in biota (nominal concentrations of 0, 10, 50 or 100 ng/g egg; measured concentrations 0, 3.0, 13.7 or 33.5 ng TBBPA-BDBPE/g egg and 0, 5.3, 26.8 or 58.1 ng BTBPE/g egg). Eggs were artificially incubated until hatching (ED28), at which point blood and tissues were collected to measure morphological and physiological endpoints, including organ somatic indices, circulating and glandular thyroid hormone concentrations, thyroid gland histology, hepatic deiodinase activity, and markers of oxidative stress. Neither compound had any effects on embryo survival through 90% of the incubation period or on hatching success, body mass, organ size, or oxidative stress of hatchlings. There was evidence of sex-specific effects in the thyroid system responses to the BTBPE exposures, with type 2 deiodinase (D2) activity decreasing at higher doses in female, but not in male hatchlings, suggesting that females may be more sensitive to BTBPE. However, there were no effects of TBBPA-BDBPE on the thyroid system in kestrels. For the BTPBE study, a subset of high-dose eggs was collected throughout the incubation period to measure changes in BTBPE concentrations. There was no decrease in BTBPE over the incubation period, suggesting that BTBPE is slowly metabolized by kestrel embryos throughout their ∼28-d development. These two compounds, therefore, do not appear to be particularly toxic to embryos of the American kestrel.
四溴双酚 A 双（2,3-二溴丙基醚）（TBBPA-BDBPE）和 1,2-双（2,4,6-三溴苯氧基）乙烷（BTPBE）均为已在鸟类体内检测到的溴化阻燃剂（BFRs），但其潜在的生物学效应在很大程度上仍是未知的。我们评估了胚胎暴露于 TBBPA-BDBPE 和 BTPBE 对一种鸟类捕食者模型——红隼（Falco sparverius）的影响。从红隼的圈养种群中获取可育的卵，并在胚胎期第 5 天（ED5）向卵内注射对照溶剂或三种浓度范围内的受试物之一（名义浓度分别为 0、10、50 或 100ng/g 卵；实测浓度分别为 0、3.0、13.7 或 33.5ng TBBPA-BDBPE/g 卵和 0、5.3、26.8 或 58.1ng BTPBE/g 卵）。这些卵被人工孵化至孵化（ED28），此时收集血液和组织，以测量形态和生理终点，包括器官体指数、循环和腺甲状腺激素浓度、甲状腺组织学、肝脱碘酶活性以及氧化应激标志物。在孵化期的 90%时间内，两种化合物均未对胚胎存活率或孵化成功率、幼体体重、器官大小或氧化应激产生影响。在 BTPBE 暴露对甲状腺系统的反应中存在性别特异性效应的证据，较高剂量下雌性而非雄性幼体的 2 型脱碘酶（D2）活性降低，这表明雌性可能对 BTPBE 更为敏感。然而，TBBPA-BDBPE 对红隼的甲状腺系统没有影响。在 BTPBE 研究中，收集了整个孵化期的高剂量卵的一部分，以测量 BTPBE 浓度的变化。在孵化期间，BTPBE 浓度没有降低，这表明 BTPBE 在其约 28 天的发育过程中被红隼胚胎缓慢代谢。因此，这两种化合物似乎对红隼胚胎的毒性并不特别大。
