Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada.
Environmental Monitoring & Reporting Branch, Ontario Ministry of the Environment, Conservation and Parks, Toronto, Ontario M9P 3V6, Canada.
Environ Sci Technol. 2021 Sep 21;55(18):12372-12382. doi: 10.1021/acs.est.1c02922. Epub 2021 Sep 9.
The presence of microplastics within the gut of animals is well documented. Whether microplastics bioaccumulate in organisms and biomagnify in food webs remains unclear and relies on the ability of microplastics to translocate to other tissues. Here, we demonstrate the widespread presence of microplastics and other anthropogenic microparticles in the gastrointestinal tract, fillet, and livers of seven species of sportfish from Lake Simcoe, Ontario, Canada. Larger fish had a higher microplastic load compared to smaller fish, but the opposite trend was observed with translocated microplastics standardized by fish mass (i.e., smaller fish contained more translocated particles per gram wet weight than larger fish). Moreover, we observed no evidence of biomagnification as there was no significant relationship between the trophic level and total or translocated microplastics per individual. Overall, this suggests that microplastics are translocating, but that excretion of translocated particles or growth dilution may be occurring rather than bioaccumulation and biomagnification. Moreover, the assemblages of shapes and material types varied among tissues, suggesting that particle characteristics may predict biological fate. Our findings highlight the need for further work to understand the mechanisms of microplastic translocation and excretion and the implications for the dynamics of microplastics accumulation in food webs and human exposure.
动物肠道内存在微塑料已得到充分证实。微塑料是否在生物体内生物累积并在食物网中生物放大尚不清楚，这取决于微塑料向其他组织转移的能力。在这里，我们在安大略省西蒙湖的七种运动鱼类的胃肠道、鱼片和肝脏中广泛发现了微塑料和其他人为的微粒。与小鱼相比，大鱼的微塑料负荷更高，但在按鱼体质量标准化的转移微塑料方面则呈现出相反的趋势（即，每克湿重的小鱼体内所含的转移颗粒多于大鱼）。此外，我们没有观察到生物放大的证据，因为个体体内的总微塑料或转移微塑料与营养水平之间没有显著关系。总的来说，这表明微塑料正在转移，但可能发生的是转移颗粒的排泄或生长稀释，而不是生物累积和生物放大。此外，不同组织中形状和材料类型的组合存在差异，这表明颗粒特征可能预测生物命运。我们的研究结果强调了需要进一步研究以了解微塑料转移和排泄的机制，以及这些机制对食物网中微塑料积累和人类暴露动态的影响。
