Microplastic particles have become ubiquitous in aquatic environments and can be found in large numbers in riverine, estuarine, and marine settings at the surface of water, in suspension, and as particles deposited at the bed. The transport and settling behavior of small microplastic particles is likely very dependent on interactions with other suspended particles. Here we show from settling tube experiments conducted in the laboratory that fragments and threads of polyvinylchloride microplastic in the size range of 63–125 µm readily flocculated with fine-grained natural sediment under relative particle number concentrations that can be observed in nature in high-turbidity estuarine and coastal environments. The implication of this flocculation is that the microplastic particles are suspended and transported incorporated in aggregates that settle faster than the individual microplastic particles. This is causing a continuous sedimentation of microplastic particles in estuarine and marine settings, resulting in increased microplastic loading for benthic life in these environments.

中文翻译：

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在环境实际浓度下聚氯乙烯微塑料和细颗粒粘性沉积物的絮凝

微生物微粒已经在水生环境中普遍存在，并且可以在河流，河口和海洋环境中的水面，悬浮液中以及沉积在河床的微粒中大量发现。小塑料微粒的运输和沉降行为可能非常依赖于与其他悬浮颗粒的相互作用。在这里，我们从实验室进行的沉降管实验中可以看到，聚氯乙烯微塑料的碎片和细丝尺寸在63–125 µ之间在高浊度河口和沿海环境中自然界中可以观察到的相对颗粒数浓度下，m容易被细粒天然沉积物絮凝。这种絮凝的含义是，将微塑料颗粒悬浮并运输，并掺入比单个微塑料颗粒沉降更快的聚集体中。这会导致在河口和海洋环境中持续沉积微塑料颗粒，从而导致这些环境中底栖生物的微塑料负载增加。