Microplastic and nanoplastic pollution and associated potential disease risks

Microplastics and nanoplastics (MNPs) are emerging pollutants widely dispersed in the environment, with humans primarily exposed through ingestion and inhalation. Although their biological effects are being increasingly studied, their potential effect on human health and disease risk remains uncertain. This Review summarises evidence on potential disease risks of human exposure to MNPs, while highlighting key limitations and research gaps. Evidence suggests that MNP exposure might elevate the risk of various diseases, including metabolic, respiratory, cardiovascular, neuroendocrine, hepatic, renal, and skin disorders, as well as infectious diseases, cancer, and ageing-related disorders. Despite extensive evidence of adverse effects in animal models and cell cultures, direct evidence linking MNP exposure to human disease risk remains scarce. A key challenge on research of MNPs lies in the scarcity of robust human exposure data and the narrow scope of existing studies on specific types of MNPs, leaving several environmentally prevalent plastic particles understudied. Addressing these gaps will require investigating the mechanisms of toxicity, relevant biomarkers, and disease pathways associated with MNP exposure. Such efforts will be essential to clarify human health risks and inform future regulatory and mitigation strategies.