Interactions Between Silver Nanoparticles and Dissolved Natural Organic Matter Under Estuarine Conditions

Silver engineered nanoparticles (AgNPs) are under rapid development for incorporation into consumer goods. Although their domestic and industrial uses increased in many countries, little is known about their fate and toxic action in aquatic and terrestrial environments. AgNPs could interact with natural organic matter (NOM) from different origins and could be transported into the ocean by this organic matter. It is important to understand the interactions developed between AgNPs and dissolved NOM. The aim of this study was to characterise the stability of AgNP colloids and their interactions with natural NOM from different sources. In nanopure water, the addition of NOM to an aqueous AgNP dispersion did not induce a large variation in the size spectra of AgNPs. However, in estuarine waters, the presence of salt and NOM changed significantly these size distribution spectra. The size of AgNPs in contact with dissolved NOM in freshwater is exacerbated as the salinity rises.