Models for assessing engineered nanomaterial fate and behaviour in the aquatic environment

Engineered nanomaterials (ENMs, material containing particles with at least one dimension less than 100 nm) are present in a range of consumer products and could be released into the environment from these products during their production, use or end-of-life. The high surface to volume ratio of nanomaterials imparts a high reactivity, which is of interest for novel applications but may raise concern for the environment. In the absence of measurement methods, there is a need for modelling to assess likely concentrations and fate arising from current and future releases. To assess the capability that exists to do such modelling, progress in modelling ENM fate since 2011 is reviewed. ENM-specific processes represented in models are mainly limited to aggregation and, in some instances, dissolution. Transformation processes (e.g. sulphidation), the role of the manufactured coatings, particle size distribution and particle form and state are still usually excluded. Progress is also being made in modelling ENMs at larger scales. Currently, models can give a reasonable assessment of the fate of ENMs in the environment, but a full understanding will likely require fuller inclusion of these ENM-specific processes