Microplastics (PN6) as secondary pollutants: The desorption of radionuclides in simulated human digestive fluids

Abstract

Plastic pollution, particularly in the form of microplastics (MPs), poses a significant threat to both, the environment and human health. Despite extensive research, gaps still exist in understanding the behavior of MPs as carriers of toxic pollutants, including radionuclides. This study investigates the desorption of uranium (U-232) and americium (Am-241) from polyamide nylon 6 (PN6) MPs under various conditions, including acidic environments and simulated human digestive systems. Results demonstrate that PN6-MPs can absorb radionuclides from contaminated waters and extensively desorb them in simulated digestive systems. The desorption efficiency is higher for Am-241 compared to U-232 across different pH ranges, suggesting a nuanced interplay between pH and desorption efficiency. Specifically, PN6-MPs can desorb up to 80 % of bound radionuclides in simulated digestive systems within 24 h and almost quantitatively after 120 h. These findings highlight the potential of PN6-MPs to act as covert carriers of waterborne pollutants, underscoring the need for further research to mitigate the risks posed by plastic pollution to both, the environment and human health.