State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Center of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510530, PR China.
State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Center of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510530, PR China.
Environ Pollut. 2024 Mar 15;345:123460. doi: 10.1016/j.envpol.2024.123460. Epub 2024 Jan 28.
Despite the increasing production, use, and ubiquitous occurrence of novel brominated flame retardants (NBFRs), little information is available regarding their fate in aquatic organisms. In this study, the bioaccumulation and biotransformation of two typical NBFRs, i.e., 1,2-bis (2,4,6-tribromophenoxyethane) (BTBPE) and 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane (TBECH), were investigated in tissues of zebrafish (Danio rerio) being administrated a dose of target chemicals through their diet. Linear accumulation was observed for both BTBPE and TBECH in the muscle, liver, gonads, and brain of zebrafish, and the elimination of BTBPE and TBECH in all tissues followed pseudo-first-order kinetics, with the fastest depuration rate occurring in the liver. BTBPE and TBECH showed low bioaccumulation potential in zebrafish, with biomagnification factors (BMFs) < 1 in all tissues. Individual tissues' function and lipid content are vital factors affecting the distribution of BTBPE and TBECH. Stereoselective accumulation of TBECH enantiomers was observed in zebrafish tissues, with first-eluting enantiomers, i.e. E-α-TBECH and E-β-TBECH, preferentially accumulated. Additionally, the transformation products (TPs) in the zebrafish liver were comprehensively screened and identified using high-resolution mass spectrometry. Twelve TPs of BTBPE and eight TPs of TBECH were identified: biotransformation pathways involving ether cleavage, debromination, hydroxylation, and methoxylation reactions for BTBPE and hydroxylation, debromination, and oxidation processes for TBECH. Biotransformation is also a vital factor affecting the bioaccumulation potential of these two NBFRs, and the environmental impacts of NBFR TPs should be further investigated in future studies. The findings of this study provide a scientific basis for an accurate assessment of the ecological and environmental risks of BTBPE and TBECH.
尽管新型溴化阻燃剂（NBFRs）的产量、使用量和普遍存在不断增加，但关于它们在水生生物体内的命运的信息却很少。在这项研究中，通过饮食向斑马鱼（Danio rerio）投喂目标化学物质，研究了两种典型的 NBFRs，即 1,2-双（2,4,6-三溴苯氧基）乙烷（BTBPE）和 1,2-二溴-4-（1,2-二溴乙基）-环己烷（TBECH）在其组织中的生物积累和生物转化。在斑马鱼的肌肉、肝脏、性腺和大脑中，均观察到 BTBPE 和 TBECH 的线性积累，并且所有组织中 BTBPE 和 TBECH 的消除均遵循拟一级动力学，肝脏中的消除速度最快。BTBPE 和 TBECH 在斑马鱼中的生物积累潜力较低，所有组织中的生物放大因子（BMFs）均<1。个体组织的功能和脂质含量是影响 BTBPE 和 TBECH 分布的重要因素。在斑马鱼组织中观察到 TBECH 对映体的立体选择性积累，优先积累先洗脱的对映体，即 E-α-TBECH 和 E-β-TBECH。此外，还使用高分辨率质谱全面筛选和鉴定了斑马鱼肝脏中的转化产物（TPs）。鉴定出了 BTBPE 的 12 种 TPs 和 TBECH 的 8 种 TPs：BTBPE 的生物转化途径涉及醚裂解、脱溴、羟化和甲氧基化反应，而 TBECH 的生物转化途径涉及羟化、脱溴和氧化过程。生物转化也是影响这两种 NBFR 生物积累潜力的重要因素，未来的研究应进一步调查 NBFR TPs 的环境影响。本研究的结果为准确评估 BTBPE 和 TBECH 的生态和环境风险提供了科学依据。
