Plain language summary of the framework for the risk assessment of manufactured nanomaterials

Official title: Plain language summary of the Framework for the Risk Assessment of Manufactured Nanomaterials under the Canadian Environmental Protection Act, 1999

The full version of the Framework for the Risk Assessment of Manufactured Nanomaterials under the Canadian Environmental Protection Act, 1999 is available.

Introduction

Nanotechnology is the study and manipulation of matter at the nanoscale (about 1 to 100 nanometres^{Footnote 1}). It is a technology with enormous innovation potential and substances developed using this technology (manufactured nanomaterials) enter the Canadian market across a wide range of applications and industries. Under the Canadian Environmental Protection Act, 1999 (CEPA), a substance is considered a nanomaterial if it meets the criteria described in Health Canada's working definition for nanomaterials and particle size distribution threshold (number or mass-based), as stated in both this framework and the Guidance Document for the notification and testing of new substances: chemicals and polymers.

Substances manufactured at the nanoscale can be designed to exhibit unique characteristics that differ from bulk (non-nanoscale) substances. For example, some nanomaterials can reflect and scatter ultraviolet light while remaining transparent, while others may reinforce mechanical structures, providing strength and durability to materials. These characteristics come from manipulating the size, shape and/or surface chemistry of bulk substances at the nanoscale. These characteristics can also alter the hazardous effects and environmental behaviour of substances relative to their bulk form and may change their potential to harm human health and the environment. Because they can exhibit unique effects and behaviours, it is important to consider the unique characteristics of nanomaterials in risk assessments.

The Government of Canada has developed a framework for the risk assessment of nanomaterials. This document describes how the Government of Canada conducts risk assessments of nanomaterials under CEPA to account for the unique characteristics exhibited by these substances.

The assessment of substances, including nanomaterials, under CEPA

The assessment of nanomaterials follows the same general principles and approaches as for bulk substances. Under CEPA, Environment and Climate Change Canada (ECCC) and Health Canada (HC) assess existing substances that are in commerce in Canada (substances on the Domestic Substances List) and new substances for import into or manufacture in Canada (not on the Domestic Substances List) to determine whether these substances present or may present a risk to the environment or to human health. Weight of evidence and precaution are used to support a risk assessment conclusion (under section 64 of CEPA).

Purpose of this framework

The framework describes how ECCC and HC conduct risk assessments of nanomaterials. With this document, ECCC and HC can communicate to industry and the public the methods that we use to make decisions under CEPA.

Scope of the framework

This risk assessment framework outlines approaches and considerations for informing risk assessments of nanomaterials under CEPA, including both existing nanomaterials on the Domestic Substances List and new nanomaterials notified under the New Substances Notification Regulations (Chemicals and Polymers).

Nanomaterial-specific risk assessment approaches

Because nanomaterials can have different behaviours than bulk substances, the information and test data used to assess bulk substances may not be applicable to nanomaterials. This means that, in some cases, ECCC and HC cannot simply use this information to characterize the hazard or potential for exposure that determines environmental or human health risks for nanomaterials. This becomes more complicated because there can exist different forms of a nanomaterial for which the hazard properties and exposure scenarios could be different. For example, a substance manufactured to have a size between 1 and 10 nm may have a different behaviour or have a different use and thus a different exposure pathway than the same substance manufactured at a size between 50 and 70 nm. Physical chemical properties of the nanomaterial are used to identify and classify nanomaterials, and this in turn helps to select the appropriate data that may support a nanomaterial risk assessment.

Nanomaterial risk assessments rely on test data and currently available models to support risk assessments. Along with expert judgment, ECCC and HC apply conservative assumptions to account for uncertainties and data quality on each nanomaterial assessed. The framework discusses in detail the nanomaterial-specific considerations for risk assessment, such as:

• the key physical and chemical properties specific for nanomaterial identification and used for grouping or classifying nanomaterials for information gathering
• the data considerations used in a nanomaterial risk assessment such as test data or modelling
• the behaviour of nanomaterials throughout the lifecycle of the nanomaterial (from production to disposal) and characterizing those potential effects on human health and the environment

The framework also details the ecological and human health risk characterization of nanomaterials as summarized below:

Ecological risk characterization approach for nanomaterials

The ecological risk characterization of nanomaterials considers relevant ecological processes that may affect the potential exposure and hazardous effects of nanomaterials. This includes investigating how nanomaterials are transported in the environment and where in the environment nanomaterials may end up (environmental fate). In addition, ECCC investigates how biotic (living components of an ecosystem) and abiotic (non-living components such as sunlight, pH and temperature) components can influence the bioavailability, persistence or adverse effects of a nanomaterial. These investigations determine the hazard potential, as well as where and in what quantity a nanomaterial may be in the environment, to characterize its overall risk to ecological components.

Human health risk characterization approach for nanomaterials

Human health risks of nanomaterials are characterized based on nanomaterial-specific hazards and exposures for relevant routes of exposure. Characterization of the risks to people in Canada are based on, but not limited to, the use of products available to consumers, exposure via food, drinking water and environmental media, and with special consideration given to the potential risks to populations who may be disproportionately impacted (for example, children, pregnant people).

Conclusion

For a nanomaterial assessed under CEPA, the potential to cause harm to the environment or human health may differ from the bulk form of the same substance and may differ among different nanoscale forms of the same substance. ECCC and HC use a weight of evidence approach to combine the multiple lines of evidence and their uncertainties to conclude whether a nanomaterial is entering or may enter the environment in a quantity or concentration or under conditions that meet any of the criteria for toxicity as set out under CEPA.

More information on the assessment of Nanomaterials under the Canadian Environmental Protection Act, 1999 is available.

For more information, please contact substances@ec.gc.ca.