水生生态系统中的铀污染对生物构成了威胁。然而,铀沿水生食物链的代谢和毒性仍然未知。这里,我们建立了一个人工水生生态系统,以研究铀沿食物链的命运并揭示其潜在的毒性。结果表明,铀对藻类的毒性具有剂量和时间依赖性,导致细胞变形并阻碍细胞增殖。当接触铀的藻类被鱼摄取时,铀往往集中在鱼的肠道系统和骨骼中。相对而言,直接的水铀暴露导致了铀在头部的显着积累,皮肤,和鱼的肌肉,表明不同的毒性取决于不同的暴露途径。与直接接触水相比,高水平的铀污染(20mgL-1)通过食物摄入加剧了对鱼类的毒性。它还显示,在藻类和鱼类中积累期间,大约25%和20%的U(VI)被还原为低价形式,分别,和超过10%的U(IV,VI)最终转换为U(0),由于较低的溶解度和生物利用度,因此减轻了铀的毒性。总的来说,这项研究为铀在水生食物链中的命运提供了新的见解,并强调了与消费受铀污染的水产品相关的风险。
Uranium pollution in aquatic ecosystems poses a threat to organisms. However, the metabolism and toxicity of
uranium along aquatic food chains remain unknown. Here, we established an artificial aquatic ecosystem to investigate the fate of
uranium along the food chain and reveal its potential toxicity. The results displayed a dose- and time-dependent toxicity of uranium on algae, leading to cell deformation and impeding cell proliferation. When
uranium-exposed algae are ingested by fish,
uranium tends to concentrate in the intestinal system and bones of fish. Comparatively, direct water
uranium exposure resulted in a remarkable
uranium accumulation in the head, skin, and muscles of fish, suggesting different toxicity depending on distinct exposure pathways. High-level uranium pollution (20 mg L-1) intensifies the toxicity to fish through food intake compared to direct water exposure. It has also revealed that approximately 25 % and 20 % of U(VI) were reduced to lower valence forms during its accumulation in algae and fish, respectively, and over 10 % of U(IV, VI) converted to U(0) ultimately, through which uranium toxicity was mitigated due to the lower solubility and bioavailability. Overall, this study provides new insights into the fate of uranium during its delivery along the aquatic food chain and highlights the risks associated with consuming uranium-contaminated aquatic products.