Mapping the toxic threat: unveiling heavy and trace metal presence in marine plastic pellets

Plastic pellets represent a significant threat to marine environments: beyond being pollutants themselves, they can act as vectors for other contaminants by absorbing organic pollutants and metals. In this study, synchrotron-based micro–X-ray fluorescence (micro-XRF) mapping was applied to spatially resolve heavy and trace metal distributions in environmental polyethylene pellets collected along the Tyrrhenian coast. By analyzing pellets exhibiting different degrees of yellowing and biofouling, the study explores the relationship between environmental exposure parameters and metal accumulation. The results distinguish surface-associated metals related to adsorption and biofouling from metals penetrating the polymer interior, particularly in aged pellets. This spatially resolved approach provides new insight into metal accumulation mechanisms and the associated environmental impact and potential risk to human health linked to plastic pellets.