Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Environ Sci Technol. 2012 Oct 16;46(20):11040-6. doi: 10.1021/es302166p. Epub 2012 Sep 25.
In this study, zebrafish (Danio rerio) were exposed to two dietary concentrations of individual HBCD diastereoisomers (α-, β-, and γ-HBCD) for 42 days, followed by clean food for 21 days, to examine bioaccumulation, depuration, and enantiomer fractions (EFs) of HBCD diastereoisomers and to test the bioisomerization of HBCDs in fish. The depuration of α-, β-, and γ-HBCD in zebrafish followed the first-order process. Bioaccumulation parameters of the three diastereoisomers differed between low and high dose, suggesting that the bioaccumulation of them is concentration dependent. Calculated assimilation efficiencies (AEs), biomagnification factors (BMFs), and half-lives (t(1/2)) of α-HBCD were the highest among the three diastereoisomers. Furthermore, the study showed that zebrafish could biotransform γ-HBCD to α-HBCD. The highest AE, BMF, and t(1/2) of α-HBCD and bioisomerization of γ-HBCD to α-HBCD could explain why α-HBCD appears to be dominant in biota samples. The EFs for α- and γ-HBCD in zebrafish estimated at different times of bioaccumulation and depuration were all significantly greater than those in corresponding food (P < 0.05), indicating selective enrichment of (+) α-enantiomer and (+) γ-enantiomer relative to (-) α-enantiomer and (-) γ-enantiomer, respectively.
在这项研究中，斑马鱼（Danio rerio）被暴露于两种不同浓度的个体六溴环十二烷对映异构体（α-、β-和 γ-HBCD）中 42 天，随后用清洁食物喂养 21 天，以研究 HBCD 对映异构体的生物积累、消除和对映体分数（EFs），并测试鱼类中 HBCDs 的生物异构化。α-、β-和 γ-HBCD 在斑马鱼中的消除遵循一级过程。三种对映异构体在低剂量和高剂量之间的生物积累参数不同，表明它们的生物积累是浓度依赖性的。计算得到的三种对映异构体的同化效率（AEs）、生物放大因子（BMFs）和半衰期（t(1/2)）中，α-HBCD 的数值最高。此外，该研究表明，斑马鱼可以将 γ-HBCD 生物转化为 α-HBCD。α-HBCD 的最高 AE、BMF 和 t(1/2)以及 γ-HBCD 向 α-HBCD 的生物异构化，可以解释为什么在生物群样本中 α-HBCD 似乎占主导地位。在不同的生物积累和消除时间点估算的斑马鱼中 α-和 γ-HBCD 的 EFs 均显著高于相应食物中的 EFs（P<0.05），这表明相对于（-）α-对映体和（-）γ-对映体，分别对（+）α-对映体和（+）γ-对映体有选择性富集。
