Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
Environ Pollut. 2022 Oct 1;310:119860. doi: 10.1016/j.envpol.2022.119860. Epub 2022 Aug 7.
Aquatic natural colloids are closely related to the environmental behavior of pollutants, which may affect their bioavailability in aquatic organisms. This study explored the potential mechanisms of the natural colloids at environmentally relevant concentrations affecting the bioaccumulation process of benzophenone-3 (BP3) in zebrafish (Danio rerio). The results of kinetic model fitting showed that the natural colloids decreased the uptake and loss rate of BP3 by zebrafish but prolonged the time to reach the cumulative equilibrium, eventually resulting in a higher cumulative concentration in zebrafish. According to the tissue concentration at equilibrium and the results of toxicokinetic analysis, the presence of high molecular colloids could enhance the bioaccumulation of freely dissolved BP3 due to its high desorption rate with BP3 in the intestines of fish, increasing the freely dissolved BP3 concentrations to which zebrafish were exposed. Both natural colloids and BP3 could enhance the cell permeability of zebrafish, which allowed colloid-bound BP3 to directly enter the fish and accumulate in its muscle. Besides, although both natural colloids and BP3 could cause the metabolic disorders in adult zebrafish, they affected the physiological and biochemical activities of zebrafish through different pathways. The disturbance of glutathione metabolism in zebrafish induced by natural colloids may be the reason for the diminished ability of zebrafish to clear and transform BP3 in the mixture system. The carrier effect of natural colloids and reduced clearance ability of zebrafish eventually increased the bioaccumulation of BP3 in zebrafish. This study highlights the significance of natural colloids at environmentally relevant concentrations on the biological effects of emerging contaminants in actual waters, however, natural colloids are always ignored in most field investigation of pollutants, which would ultimately lead to an underestimation of the true ecological risk of pollutants.
水生天然胶体与污染物的环境行为密切相关，可能会影响其在水生生物中的生物有效性。本研究探讨了在环境相关浓度下天然胶体的潜在机制，这些机制可能会影响二苯甲酮-3（BP3）在斑马鱼（Danio rerio）中的生物积累过程。动力学模型拟合结果表明，天然胶体降低了 BP3 在斑马鱼体内的摄取和损失率，但延长了达到累积平衡的时间，最终导致斑马鱼体内的累积浓度更高。根据平衡时的组织浓度和毒代动力学分析结果，高分子胶体的存在可以通过其在鱼肠道中与 BP3 的高解吸率来增强自由溶解 BP3 的生物积累，增加斑马鱼暴露的自由溶解 BP3 浓度。天然胶体和 BP3 都可以增强斑马鱼的细胞通透性，使胶体结合的 BP3 能够直接进入鱼体内并在其肌肉中积累。此外，尽管天然胶体和 BP3 都可以导致成年斑马鱼的代谢紊乱，但它们通过不同的途径影响斑马鱼的生理和生化活性。天然胶体引起的斑马鱼谷胱甘肽代谢紊乱可能是混合体系中斑马鱼清除和转化 BP3 能力下降的原因。天然胶体的载体作用和斑马鱼清除能力的降低最终增加了 BP3 在斑马鱼体内的生物积累。本研究强调了在实际水体中，环境相关浓度下天然胶体对新兴污染物生物效应的重要性，然而，在大多数污染物的野外调查中，天然胶体往往被忽视，这最终会导致对污染物真实生态风险的低估。
