Bioaccumulation assessment of nanomaterials cannot be done using the equilibrium partitioning method commonly used for organic chemicals. Therefore, the current guidance on bioaccumulation assessment is not suitable for nanomaterials. To address this issue, the OECD has proposed a tiered approach designed specifically for nanomaterials. This approach is tailored for metallic and metal oxide particles but can likely be extended to other advanced (nano)materials as well.

Integrated approaches to testing and assessment (IATAs) can optimise testing strategies and minimise the use of test animals in chemical risk assessment. Recently, aquatic IATAs have been developed that efficiently integrate the limited information on the fate and effects of nanomaterials. This approach can significantly improve the risk assessment of nanomaterials. However, IATAs are not yet widely accepted or implemented in regulatory risk assessment.