Department of Ocean Science, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong; School of Environment and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
School of Environment and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
J Hazard Mater. 2018 Oct 15;360:420-427. doi: 10.1016/j.jhazmat.2018.07.085. Epub 2018 Aug 3.
Bioaccumulation and biotransformation are critical processes modifying toxicity of easily metabolizable chemicals to aquatic organisms. In this study, tissue-specific accumulation, biotransformation and elimination of a current-use pesticide fipronil in tilapia (Oreochromis niloticus) were quantified by combining in vivo measurements and a newly developed multi-compartmental toxicokinetic model. Waterborne fipronil was taken up via gills and metabolized rapidly and solely to fipronil sulfone. Significant decrease of fipronil residues in liver and intestine during exposure period strongly suggested the induction of metabolism in these two organs. Significant transport of fipronil and fipronil sulfone in the liver-bile-intestine system implied that hepatobiliary excretion and enterohepatic re-absorption played important roles in fipronil metabolism and system circulation of the parent compound and the metabolite. The multi-compartmental model quantitatively described the highly dynamic inter-compartmental transport and rapid branchial clearance of fipronil in fish. Modeling results also suggested that uptake and biotransformation were the stronger driving forces for the inter-compartmental transport of fipronil in fish than the inherent partitioning capacity. Overall, our findings highlight the importance of biotransformation on internal disposition of fipronil in fish, which helps to improve aquatic toxicity assessment of this pesticide.
生物积累和生物转化是改变易代谢化学物质对水生生物毒性的关键过程。在这项研究中，通过结合体内测定和新开发的多室毒代动力学模型，定量研究了当前使用的杀虫剂氟虫腈在罗非鱼（Oreochromis niloticus）中的组织特异性积累、生物转化和消除。氟虫腈通过鳃吸入水体，并迅速且仅转化为氟虫腈砜。暴露期间肝和肠中氟虫腈残留量的显著减少强烈表明这两个器官中代谢的诱导。氟虫腈和氟虫腈砜在肝-胆-肠系统中的显著转运表明，肝胆排泄和肠肝再吸收在氟虫腈代谢和母体化合物及代谢物的系统循环中发挥重要作用。多室模型定量描述了氟虫腈在鱼体内的高动态室间转运和快速鳃清除。模型结果还表明，与内在分配能力相比，摄取和生物转化是氟虫腈在鱼体内室间转运的更强驱动力。总的来说，我们的研究结果强调了生物转化对氟虫腈在鱼类体内分布的重要性，有助于提高该农药的水生毒性评估。
