In a study designed to investigate the fate of engineered silver nanomaterials in complex natural systems, researchers have determined that these materials can move from soils to sediments, and remain bioavailable, suggesting that erosion and runoff is a potential pathway through which silver nanoparticles can enter waterways.
The study, Long-Term Transformation and Fate of Manufactured Ag Nanoparticles in a Simulated Large Scale Freshwater Emergent Wetland, conducted by researchers at Baylor University, Carnegie Mellon University, Duke University, and the Center for the Environmental Implications of NanoTechnology and published in Environmental Science & Techology, was carried out in a simulated emergent freshwater wetland to whose soils and water column silver nanoparticles were applied.
Eighteen months later, about 70% of the silver nanoparticles remained in the soils and sediments to which they were applied. But the movement of additional particles from soil to sediment suggest that this may be a route through which such nanomaterials can enter waterways. In addition, researchers measured the uptake of the silver nanoparticles in plants, fish, and insects in the engineered environment, leading to the conclusion that these compounds remained bioavailable after chemical transformation that occurred as they passed through the wetland system.