Sorption of Pb and Cu on different types of microplastics

The studies on the effect of different plastic properties (e.g., types, shapes, presence of additivies) on the sorption of contaminants in the agricultural environment are limited. In this study, Cu and Pb, the commonly found heavy metals in the environment, were used to investigate the sorption capacities of microplastics (MPs). The Pb sorption capacity increased in the order of polystyrene (PS)<polyethylene (PE)<polyvinyl chloride (PVC). The estimated Cu sorption capacity was greater for the PE films than the PE fragments, while the sorption strength was greater for the PE fragments. This suggests that the shapes of MPs can affect the contaminant sorption capacities. With the PE fragments, the Pb sorption capacity was greater than the Cu sorption capacity by 10-12 times. Also, the Pb and Cu sorption capacities were greater for the PE fragments with additives than the PE fragment without additives. After the sorption of Pb or Cu on MPs, the toxic effects of the Pb or Cu solutions were decreased, suggesting that the toxic effects of contaminants can be affected by the co-presence of MPs in the environment. Overall, the results show that different types and shapes of MPs and the presence of additives can affect the heavy metal sorption capacities of MPs.