Abstract

Scientists evaluate the risks from exposure to chemical substances by testing the effects that chemicals have on humans and on other species, such as fish. However, testing substances for the full set of effects requires a lot of time, money and test animals. To minimize costs and animal use, the existing data for similar substances can be used to fill data gaps for a chemical substance via a process called read-across. This approach is also applied for nanomaterials. RIVM has commissioned the development of a strategy to evaluate the potential for read-across in cases of missing data for nanomaterials, with a focus on fulfilling data requirements in regulatory frameworks. To develop this strategy, a literature review was compiled on physicochemical parameters (such as the rate at which and amount to which a chemical dissolves) and their relevance for the behaviour, fate and toxicity of nanomaterials in organisms and the environment. This review was based on current knowledge on the behaviour and toxicity of nanomaterials. It resulted in a base set of physico-chemical parameters that are essential to characterise a nanomaterial and substantiate possibilities for read-across. The strategy provides a framework in which to evaluate each nanomaterial and decide on the applicability of readacross for nanomaterials. The strategy has proven useful in two hypothetical case studies (nanosilver and nanotitanium dioxide). Nevertheless, it was concluded that improvement is needed for the documentation of the information from the laboratory testing of nanomaterials to support read-across. Particularly relevant physico-chemical properties of the nanomaterials and test conditions need more detailed descriptions. Furthermore, the scientific community needs to continue developing test methods that can characterize certain behaviours of nanomaterials to support read-across.