Human Toxicity of Nano‐ and Microplastics

The toxicity of microplastics to human beings has raised global concern because of the ubiquity of these emergent pollutants in the environment and their entrance into trophic chains. This chapter reviews the advances and challenges in assessing toxicity in humans based on the analysis of basic concepts of toxicology and recent research results. The challenges and scope of applying animal studies, cell- and tissue-based toxicology assays, in silico or computational models, tissue engineering, organ-in-chip engineering, and human dosing studies are discussed. The analysis of the results of toxicity studies with nano- and microplastics, based on the revision of 85 research articles, showed that toxicity tests were mainly performed with mice and human cells, while polystyrene, polyethylene, polyethylene terephthalate, and polyvinyl chloride were the most common plastics tested. The main results regarding particle uptake, cell viability, stress response, cancer, genomic effects, and toxicity in the reproductive system are described. While the results show, in most cases, a negative effect associated with the presence of micro- and nanoplastics, differences in methodologies and research approaches make it difficult to establish clear cause–effect relationships.