Y. Zhang, MC. Sauve, D. Vladisavljevic, K. Nguyen, M. Zein Aghaij, C. Lemieux
Keywords: manufactured nanomaterials, Domestic Substances List, regulatory risk sssessment, risk assessment framework
Summary:Health Canada and Environment and Climate Change Canada have undertaken an initiative to assess manufactured nanomaterials (MNMs) listed on the Domestic Substances List (DSL) that are in-commerce in Canada for risk to human health and the environment. This presentation will demonstrate results of a data gap analysis on the information relevant to human health assessment of DSL MNMs, as well as showcase a science-based approach for developing a regulatory risk assessment framework (RAF) for assessing risks of MNMs to human health and the environment. Previously, over 50 MNMs were identified in commerce in Canada based on the information of production/import volume and uses obtained from a mandatory survey under section 71 (s.71) of the Canadian Environment Protection Act (CEPA, 1999), as well as additional literature search on uses, hazard, and physical-chemical properties. These MNMs were subjected to further analysis using a matrix approach and were placed in four different bins corresponding to their exposure and hazard bands. This exercise amassed relevant existing information, and determined data gaps with respect to our knowledge of hazards and exposures for given MNMs. Available information for each MNM was mapped out and data needs for conducting a regulatory risk assessment were identified. Ongoing strategies for filling these data gaps via research and information gathering initiatives will be discussed. A science-based regulatory risk assessment framework (RAF) has been drafted to enable assessment and management of MNMs within the Canadian regulatory context. The RAF is established on the traditional risk assessment paradigm for chemicals, but incorporates the unique aspects of nanomaterials. It outlines important issues regarding different elements in a nano-specific risk assessment, including substance identity, exposure sources/exposure scenarios, life cycle, and environmental fate. It also provides potential options for addressing these issues and highlights strategies for read-across and/or use of alternative test methods in hazard identification. Other overarching issues, such as grouping of MNMs and associated uncertainties, are also discussed. As a next step, following RAF development, case studies using relatively data-rich metal oxide MNMs will be conducted. These case studies will allow application of the RAF using concrete examples, leading to refinement of the RAF as needed. A systematic evaluation of in-commerce MNMs will ensure that the risks of these nanomaterials will be appropriately managed in Canada.