Interaction of Microplastics and Organic Pollutants: Quantification, Environmental Fates, and Ecological Consequences

Abstract

Microplastics which act as vectors for organic pollutant transport in environment have raised increasing concerns recently. This paper provides an overview on the interaction of plastic debris or microplastics with these organic chemicals and its effects on biological receptors. Plastic additives represented one of the most important organic pollutants associated with microplastics; the types, quantification, and migration from the plastic debris or microplastics are addressed here. In addition to the chemical additives, microplastics also adsorbed hydrophobic or hydrophilic organic pollutants from the environments due to their high surface areas and affinity for these pollutants. The mechanisms of microplastic adsorption for PAHs, PCBs, and pharmaceutics and the role of microplastic surface and solution chemistry were well discussed in the paper. The sorption affinity changed by the aging of microplastic surface was of concern in particular. The organic pollutants in the microplastics may cause toxic effects on biotas by releasing into the leachate or by contact exposure directly through microplastics ingestion. Here we reviewed the latest reports on the organic pollutant assay for the leachates from the environmental microplastics and their toxic effects on freshwater species Daphnia magna, brown mussel (Perna perna), barnacle, and microalgae using different endpoints. Bioaccumulation of organic pollutants and biological toxicology through the vector effects of microplastics were also reviewed in the paper. However, large uncertainties existed among the different studies with respect to the toxic effects of co-exposure with organic pollutants and microplastics. Therefore, further researches are recommended to be done regarding the combined effects of organic pollutants and microplastics under the different exposure scenarios.