In the OECD Expert Meeting in Berlin 2013 (OECD, 2014a), it was identified that dissolution rate and dispersion stability in the environment are important parameters for nanomaterials, i.e. these parameters are main drivers in environmental fate of nanomaterials and nanomaterials (bio)availability, and as such important in environmental risk assessment of nanomaterials. It was concluded that Test Guidelines (TGs) should be developed for these parameters. As these parameters are often interlinked it was acknowledged that an overarching guidance document (GD) would be beneficial as well.
A Test Guideline (TG 318, OECD 2017) on dispersion stability of manufactured nanomaterials in simulated environmental media is already available since 2017.
A number of projects are being developed simultaneously at OECD to address different environmental parameters. For example, a TG on dissolution rate in environmental media which purpose
is to develop and adequately validate a robust method in standardised conditions for dissolution of nanomaterials. Meanwhile, also other relevant methods for dissolution rate testing in water and biological fluids as well as transformation in the environment will be included in upcoming TG and GD for nanomaterials. In view of the current lack of harmonised methods, this GD includes dissolution relevant content based on available information in scientific literature, and GD 29 (OECD 2001) also takes into account the current draft document on dissolution rate in environmental media. In doing so, the GD
provides interim guidance on experimental steps and procedures of batch and dynamic flow-through methods and decision support when to use them for nanomaterials (Chapter until new TGs and GDs become available. When these OECD projects are finalised and TGs available, an update of this GD might be needed…