International Journal of Science, Engineering and TechnologyAuthors: John Chimerenka Ifenkwe
Abstract: Microplastics are an emerging global contaminant with profound implications for human and environmental health. Defined as plastic particles 1 µm to 5 mm in size, and nanoplastics less than 1µm (<1000 nm), these particles originate from primary manufacturing and secondary degradation of larger plastics. Their ubiquity in air, water, soil, food, and biological tissues has raised significant toxicological concern because microplastics are not inert. They act as physical particulates, chemical vectors for plasticizers, flame retardants, heavy metals, and as carriers for microbial pathogens and persistent organic pollutants. Upon inhalation, ingestion, or dermal contact, microplastics can induce oxidative stress, chronic inflammation, endocrine disruption, immune dysregulation, gut microbiome alteration, and potential genotoxicity. Evidence from in vitro, animal, and emerging human biomonitoring studies suggests associations with respiratory dysfunction, reproductive toxicity, developmental effects, and cardiovascular risk. This review consolidates existing evidence on microplastic sources, human exposure routes, mechanisms of toxicity, and associated health outcomes, while underscoring the critical need for standardized detection protocols, systematic human biomonitoring, development of safer polymers, and effective environmental remediation.
