Micro- and Nanoplastics in the Environment: Current State of Research, Sources of Origin, Health Risks, and Regulations—A Comprehensive Review

Small-particle-produced goods, such as those used in industry, medicine, cosmetics, paints, abrasives, and plastic pellets or powders, are the main sources of microplastics. It is also possible to mention tire recycling granules here. Larger components break down in the environment to generate secondary microplastics. Microplastics, or particles smaller than 5 mm, and nanoplastics, or particles smaller than 1 μm, are the products of degradation and, in particular, disintegration processes that occur in nature as a result of several physical, chemical, and biological variables. Polypropylene, polyethylene, polyvinyl chloride (PVC), polystyrene, polyurethane, and polyethylene terephthalate (PET) are among the chemicals included in this contamination in decreasing order of quantity. Micro- and nanoplastics have been detected in the air, water, and soil, confirming their ubiquitous presence in natural environments. Their widespread distribution poses significant threats to human health, including oxidative stress, inflammation, cellular damage, and potential carcinogenic effects. The aim of this article is to review the current literature on the occurrence of micro- and nanoplastics in various environmental compartments and to analyze the associated health consequences. The article also discusses existing legal regulations and highlights the urgent need for intensified research into the toxicological mechanisms of microplastics and the development of more effective strategies for their mitigation.