Lu Na, Zhang Yaya, Mu Qinglin, Li Yijun, Li Yuanyuan, Yan Zhongyong, Wang You
Department of Marine Ecology, College of Marine Life Sciences, Ocean University of China, No.5 Yushan Road, Qingdao, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, No.1 Wenhai Road, Qingdao, China.
Zhejiang Marine Ecology and Environment Monitoring Center, No.20 Tiyu Road, Zhoushan, China.
Aquat Toxicol. 2024 Mar;268:106853. doi: 10.1016/j.aquatox.2024.106853. Epub 2024 Feb 4.
Hexabromocyclododecane (HBCD), third-generation brominated flame retardants (BRFs), has aroused worldwide concern because of its wide application and potentially negative impacts on marine ecosystems, but an information gap still exists regarding marine low-trophic organisms. Brachionus plicatilis, the model marine zooplankton, was used in the present study, and its reproductive responses were used as the endpoint to indicate HBCD-induced toxicity. HBCD was suggested to be extremely highly toxic compounds regarding the 96 h-LC of 0.58 mg L. The sublethal exposure of HBCD injured the reproduction of B. plicatilis: The total number of offspring per female and the key population index calculated from the life table, including the intrinsic rate of population increase (r) and net reproductive rate (R), were significantly influenced in a concentration-dependent manner. The reproductive process was also altered, as indicated by the first spawning time, first hatching time and oocyst development time. At the same time, individual survival and growth (body length) were also negatively affected by HBCD. Reactive oxygen species (ROS) were suggested to be responsible for reproductive toxicity mainly because the total ROS contents as well as the main components of •OH and HO greatly increased and resulted in the oxidative imbalance that presented as malondialdehyde (MDA) elevation. Simultaneous activation of the glutathione antioxidant system was accompanied by the apoptosis marker enzymes Caspase-3 and 9, as well as the correlation between ROS content, physiological alteration and cell apoptosis, providing further evidence for this. The integrated biomarker response (IBR) and adverse outcome pathway (AOP) showed that HBCD had a significant toxic effect on B. plicatilis near the concentration range of 96 h-LC. The establishment of this concentration range will provide a reliable reference for future environmental concentration warning of HBCD in marine.
六溴环十二烷（HBCD）作为第三代溴化阻燃剂（BRFs），因其广泛应用及其对海洋生态系统的潜在负面影响而引起了全球关注，但在海洋低营养级生物方面仍存在信息空白。本研究使用了典型的海洋浮游动物褶皱臂尾轮虫，并将其生殖反应作为指示HBCD诱导毒性的终点。就96小时半数致死浓度为0.58毫克/升而言，HBCD被认为是剧毒化合物。HBCD的亚致死暴露损害了褶皱臂尾轮虫的繁殖：每个雌性的后代总数以及根据生命表计算的关键种群指数，包括种群内禀增长率（r）和净生殖率（R），均受到显著的浓度依赖性影响。生殖过程也发生了改变，这体现在首次产卵时间、首次孵化时间和卵囊发育时间上。同时，个体存活和生长（体长）也受到HBCD的负面影响。活性氧（ROS）被认为是生殖毒性的主要原因，主要是因为总ROS含量以及•OH和HO的主要成分大幅增加，导致氧化失衡，表现为丙二醛（MDA）升高。谷胱甘肽抗氧化系统的同时激活伴随着凋亡标记酶半胱天冬酶-3和9，以及ROS含量、生理变化和细胞凋亡之间的相关性，为此提供了进一步的证据。综合生物标志物反应（IBR）和不良结局途径（AOP）表明，在96小时半数致死浓度附近的浓度范围内，HBCD对褶皱臂尾轮虫具有显著的毒性作用。该浓度范围的确定将为未来海洋中HBCD的环境浓度预警提供可靠参考。
