Interaction of freshwater microplastics with biota and heavy metals: a review

The worldwide contamination of waters by microplastics is an emerging health and environmental issue. Despite being relatively inert, microplastics may adsorb and carry other aquatic pollutants such as heavy metals. Adsorption of heavy metals onto microplastics is a spontaneous process controlled by the microplastic surface. Marine microplastics have been well discussed, yet there are actually a few reviews on microplastics in freshwater. Here, we review microplastic contamination in freshwater systems with focus on adsorption of heavy metals. We present microplastic abundance, distribution, impact of microplastic size, affinity for heavy metals and combined toxic effects of the co-occurrence of microplastic and heavy metals. Remarkably, the concentration of metals on polystyrene and polyvinyl chloride was 800 times higher than in the surrounding environment. Combined toxic effects include endocrine disrupting and reduced predatory behavior of aquatic carnivores.