The Missing Exposure Variable: Why Microplastic and Nanoplastics Epidemiology Needs Scalable Human Biomonitoring

Microplastics and nanoplastics have been reported in human tissues and fluids, but their long-term health implications remain difficult to establish. Emerging human studies provide valuable evidence while relying on specialized laboratory workflows and heterogeneous measurements, including polymer mass and particle counts that are not directly interchangeable. Understanding exposure–disease relationships will require prospective investigations analogous to the Framingham Heart Study, combining large cohorts, repeated exposure measurements, and long-term clinical follow-up. Such research depends on accessible, reproducible, and quantitatively interpretable biomonitoring methods. This perspective examines the analytical and operational barriers to longitudinal population studies and outlines requirements for scalable measurement. Closing this gap would strengthen the connection between experimental mechanisms, human tissue findings, and population-level evidence relevant to public health.