The bioaccumulation of engineered nanomaterials in aquatic organisms: bioavailability, uptake mechanisms and a tiered approach to testing
Professor Richard D. Handy, University of Plymouth
Friday 13 March 2020
The environmental bioaccumulation hazard of engineered nanomaterials (ENMs) in aquatic organisms is poorly understood, especially the effects of aged nanomaterials. This presentation aims to describe the mechanisms of bioaccumulation of pristine and aged nanomaterials in fish, especially using data from the EU Nanofase project (http://nanofase.eu/). The bioavailability of ENMs in the gut lumen depends on the physico-chemical properties of the materials, the composition of the gut lumen fluids (ionic strength, pH, organic matter, etc.) and the location and specificity of the transport pathways in the gut epithelium. In vivo studies with Ag nanoparticles (NPs) and Ag2S NPs show that the bioavailability of ENMs in trout is a few percent of the dose, as expected. The target organs include the gastrointestinal tract and the liver. The organ pathologies from these types of exposures are being documented in fish and other wildlife. We have also proposed a change to the overall testing strategy to a tiered approach that considers animal welfare and alternatives to using vertebrate animals in vivo, including in silico modelling, read across from earthworm bioaccumulation tests, an in chemico digestibility assay to assess bioavailable fractions and ex-vivo measurements on gut sacs of fish.