Unseen Hazards—Toxicological Effects and Human Health Impacts of Nanoplastics and Microplastics

Environmental pollution with microplastics (MPs) and nanoplastics (NPs) continues to increase. These pollutants have been found in the environment (water, soil, and air) as well as in human tissues and biological fluids. Oral, inhalation, and dermal pathways play key roles in human exposure to plastic particles. The primary sources of exposure are foods, beverages, air, and dust. Polymers can penetrate the skin primarily via endocytosis, exocytosis, passages through cell-to-cell junctions, and interaction with the extracellular matrix. However, the health effects of dermal exposure remain poorly understood. Microplastics and NPs have been detected in the gastrointestinal, respiratory, circulatory, urinary, reproductive, and nervous systems, causing detrimental effects in each. Such effects include oxidative stress, inflammation, cellular damage, and protein aggregation. Furthermore, their presence has been linked to cardiovascular and neurodegenerative diseases. However, standardized protocols for analyzing NPs and MPs in human organs and tissues have not yet been established or legally regulated. Further research is needed to fully determine exposure thresholds, but legislative and lifestyle changes can already be implemented.