Currently, there is an increasing body of research aimed at uptake and toxicity of nanomaterials in terrestrial ecological receptors; however, many studies fail to take into account biogeochemical transformations of nanomaterials that occur in natural and engineered environments such as in wastewater streams, during wastewater treatment, after introduction into natural soils and within organisms after their uptake or due to interactions with organisms. This presentation will discuss how surface coatings are transformed in the environment and how these transformations impact binding to solid phases in natural soils as well as their bioavailability. The first focus is on how charge of polymer coatings influences binding of Ag and ZnO nanoparticles to soils and how this subsequently influences mobility in soil. The second focus is on how charge of polymer coatings on CeO2 nanoparticles influences their bioavailability and how binding of natural organic matter to these surfaces influences bioavailability and toxicity in the nematode Caenorhabditis elegans. The results of these two studies demonstrated that while the charge and molar mass of Ag, CeO2 and ZnO nanoparticle coatings has a profound influence on their environmental behavior, bioavailability and toxicity, this influence is rapidly lost in complex environmental media as the coatings are degraded or transformed. The final focus is on how nanomaterial bioavailability changes as a result of trophic transfer, presumably due to acquisition of a protein corona within organisms occupying different trophic positions. Studies in this area focus on Au nanomaterials and demonstrate how bioavailability is increased when nanomaterials are taken up through trophic transfer. Taken as a whole, these studies indicate that biogeochemical transformations need to be considered when investigating interactions between nanoparticles and environmental, biological or engineered surfaces.

Influence of nanoparticle coatings on environmental behavior and bioavailability: The role of transformations

248th National Meeting (2014)

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