Silent Amazon Project: bioaccumulation of poly and perfluoroalkyl substances (PFAS) in aquatic macrophytes from the Amazon River

Irene de Prado Ponga

Poly and perfluoroalkyl substances (PFAS) are highly persistent pollutants which produce harmful effects to marine and freshwater wildlife. Biodiversity in the Amazon River in Brazil and its river mouth could be threatened by the several PFAS sources alongside its basin, namely the pesticide sulfluramid, which use is permitted in the country. In this study, PFAS concentrations of three aquatic macrophyte species (Eichhornia crassipes, Eichhornia azurea and Pontederia rotundifolia) living in different habitats (open river and urban areas) through 1600 km of the Amazon River were analyzed in order to assess their contamination level, bioaccumulation capacity in different internal parts, and chemical profile regarding PFAS families and chain lengths. Moreover, results of this study were compared with results of similar studies from other countries. P. rotundifolia was the most suitable species for PFAS phytoremediation as they bioaccumulated more the most abundant more hydrophilic short-chain PFAS in aerial parts. Sulfluramid was probably not the main PFAS pollution source in the Amazon River, as Amazonian macrophytes presented lower concentrations than macrophytes in other countries. Anthropogenic pollution from urban areas seems to be the biggest contributor of PFAS bioaccumulation in macrophytes. These results should guide future PFAS phytoremediation directives in the Amazon River basin.