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Microplastic properties and their interaction with hydrophobic organic contaminants: a review

Environmental Science and Pollution Research 2022 169 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Archana Prajapati, Atul N. Vaidya, Asirvatham Ramesh Kumar

Summary

This review examines the physical and chemical properties of microplastics that determine how they interact with hydrophobic organic contaminants in the environment. Researchers found that factors like polymer type, particle size, weathering, and surface chemistry all influence how strongly microplastics bind to co-occurring pollutants. The findings suggest that microplastics can serve as carriers for harmful chemicals, potentially increasing exposure risks for organisms that ingest them.

Microplastics (MPs) have been defined as particles of size < 5 mm and are characterized by hydrophobicity and large surface areas. MPs interact with co-occurring hydrophobic organic contaminants (HOCs) via sorption-desorption processes in aquatic and terrestrial environments. Ingestion of MPs by living organisms may increase exposure to HOC levels. The key mechanisms for the sorption of HOCs onto MPs are hydrophobic interaction, electrostatic interaction, π-π interactions, hydrogen bonding, and Van der Waals forces (vdW). Polymer type, UV-light-induced surface modifications, and the formation of oxygen-containing functional groups have a greater influence on electrostatic and hydrogen bonding interactions. In contrast, the formation of oxygen-containing functional groups negatively influences hydrophobic interaction. MP characteristics such as crystallinity, weathering, and surface morphology affect sorption capacity. Matrix properties such as pH, ionic strength, and dissolved organic matter (DOM) also influence sorption capacity by exerting synergistic/antagonistic effects. We reviewed the mechanisms of HOC sorption onto MPs and the polymer and matrix properties that influence the HOC sorption. Knowledge gaps and future research directions are outlined.

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