Nanoplastics and Cardiovascular Health: A Review of Environmental Exposure, Biological Mechanisms and GeoHealth Implications

Background: Plastic production and waste have expanded rapidly, and small plastic particles are now documented across environmental compartments and in several human tissues. Nanoplastics are of particular concern because their small size, large specific surface area and dynamic biomolecular corona may alter transport, cellular uptake and toxicity. Objective: This narrative review synthesises evidence on environmental exposure to micro- and nanoplastics, cardiovascular mechanisms, emerging human observations and the GeoHealth dimensions of risk, and it explicitly separates evidence of exposure from evidence of causation. Methods: The review was organised around four domains: (i) environmental sources and pathways; (ii) internal distribution and analytical measurement; (iii) vascular, inflammatory and thrombotic mechanisms; and (iv) population-level inequities and governance. A curated bibliography of 69 sources was screened for relevance, with emphasis on human tissue studies, mechanistic experiments, atmospheric transport, cardiovascular epidemiology and analytical methods. Evidence was graded by study type and by its position along an exposure-to-outcome chain. Results: Exposure may occur through inhalation, ingestion and dermal contact, with atmospheric transport, road–tyre wear, drinking water, food systems and waste streams producing geographically heterogeneous mixtures. Experimental evidence supports oxidative stress, endothelial barrier disruption, inflammation, cellular senescence, inflammasome activation and altered coagulation as plausible pathways. Human studies have reported plastic particles in blood, lung, placenta, vascular tissue, heart tissue and atheroma. One observational clinical study associated particles in carotid atheroma with higher subsequent cardiovascular event rates. Measurements nevertheless remain method-dependent, and observational evidence does not yet establish causality. Conclusion: Nanoplastics should be treated as an emerging environmental cardiovascular hazard within a One Health and GeoHealth framework. Progress requires harmonised detection, exposure reconstruction, longitudinal cohorts, mixture-aware toxicology, spatially resolved monitoring and prevention policies that address the full plastic life cycle.