Microplastics in Human Tissues: Sources, Distribution, Toxicological Effects, and Health Implications

Microplastics (MPs), plastic particles smaller than 5 mm, are ubiquitous environmental contaminants now detected in diverse human tissues, fluids, and food products.Common polymers include polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC).Exposure occurs via ingestion, inhalation, and dermal contact from sources like plastic packaging, air pollution, and contaminated food.MPs have been found in human milk, placenta, lung, blood, cartilage, and even myocardial tissue, with concentrations varying by age and exposure.Analytical methods such as FTIR, Raman spectroscopy, and pyrolysis-gas chromatography-mass spectrometry enable detection and identification, though challenges remain regarding size limits, contamination, and standardization.Toxicological studies reveal MPs can induce cellular apoptosis, oxidative stress, inflammation, and metabolic disruption, with implications for respiratory, cardiovascular, reproductive, and developmental health.Despite growing evidence, research gaps include mechanisms of biotranslocation, chronic health effects, and mitigation strategies.This review integrates current knowledge from environmental matrices to human health outcomes, emphasizing the need for interdisciplinary research and regulatory frameworks to reduce human MP exposure and address associated health risks.