Summary of public comments received on the draft framework for the risk assessment of manufactured nanomaterials
Official title: Summary of public comments received on the draft Framework for the Risk Assessment of Manufactured Nanomaterials under the Canadian Environmental Protection Act, 1999
Comments on the draft Framework for the Risk Assessment of Manufactured Nanomaterials (NMs) under the Canadian Environmental Protection Act, 1999 were submitted by Cancarb Ltd., Cabot Corp., Chemistry Industry Association of Canada (CIAC), International Carbon Black Association (ICBA), Food, Health & Consumer Products of Canada (FHCP), Magemi Mining Inc., Nickel Producers Environmental Research Association (NiPera), Synthetic Amorphous Silica and Silicate Industry Association (SASSI), and Food, Health & Consumer Products of Canada (FHCP).
Summarized public comments and responses are provided below, organized.
General comments
Comment summary 1: The European Food Safety Authority (EFSA) and the United States Food and Drug Administration (US FDA) approaches for risk assessment should be considered.
Response 1: The risk assessment of nanomaterials follows the approach for the assessment of substances in Canada under the Canadian Environmental Protection Act, 1999 (CEPA) (see section 2 of the framework and Risk assessment of chemical substances - Canada.ca). Approaches used by other jurisdictions such as the EFSA and Europe’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) were considered in the development of the draft Framework for the Risk Assessment of Manufactured Nanomaterials under the Canadian Environmental Protection Act, 1999 (the framework) and help to reinforce some of the specific considerations taken for assessment of nanomaterials under CEPA.
Additionally, information and outcomes from assessments of nanotechnology substances completed by other jurisdictions, including the EFSA and US FDA, may be considered as part of the weight of evidence approach for substances being assessed in Canada (section 2.2 and 2.3).
Comment summary 2: We support and recognize the challenges in characterizing nanomaterials, the limitation of using Chemical Abstracts Service Registry Numbers (CAS RNs), the use of proper dose metrics, as well as the use of new alternative methods for hazard prediction.
Response 2: Noted.
Comment summary 3: We support the use of Regulatory Cooperation Council (RCC) and Organisation for Economic Co-operation and Development (OECD) testing guidelines on nanomaterials, and alignments with industry on detection methods.
Response 3: Noted.
Comment summary 4: We support the case-by-case approach for environmental fate and a precaution and weight of evidence approach in risk characterization.
Response 4: Noted.
Comment summary 5: Alignment is needed with other Government of Canada programs on assessing nanomaterials in health products and foods. Use information from CEPA mandatory surveys should be shared with Government of Canada Food and Health Product programs.
Response 5: Standard practice for risk assessment under CEPA is to have regular communication, discussion and information sharing with other Government of Canada programs, including those assessing nanomaterials in food and health products, and to have Government of Canada partners review relevant assessments conducted under CEPA.
Comment summary 6: Consider alignment with international bodies on strategies for filling data gaps.
Response 6: Strategies for filling data gaps for the assessment of nanomaterials, such as the generation or the use of experimental data and/or use of predictive tools, are in line with strategies used for assessing other types of substances under the Chemicals Management Plan (CMP) in Canada, as described in Approaches for addressing data needs in risk assessment - Canada.ca. The framework includes using data from multiple sources, including international bodies, where appropriate for filling data gaps (section 2.2).
When needed, the use of grouping and read-across to fill in data gaps also aligns with what the OECD Working Party on Manufactured Nanomaterials (WPMN) is exploring (for example, WPMN No. 64, No. 76, case study on nano-TiO2), as well as with other jurisdictions, such as the European Chemical Agency (ECHA) guidance for chemical registration under REACH regulation of the European Union (EU).
Comment summary 7: The framework is consistent with the previous RCC discussion and international approaches in that the same general principles and approaches for assessment of traditional chemicals are being used for nanomaterials.
Response 7: Noted.
Comment summary 8: Moving forward, to ensure transparency and awareness, we would like to receive a formal pre-publication notice on any Government of Canada publications related to nanomaterial assessment initiatives. In addition, we would like to receive a red-line copy outlining the changes made in comparison to the pre-publication consultation version.
Response 8: Noted. For the assessment of substances which are found on the Plan of Priorities, documents are reviewed by independent peer reviewers prior to the publication of the draft. The draft documents are also published for 60-day public comment period. Providing documents in tracked changes or “red-line copies” is not a service that the program offers. The program distributes a quarterly publication plan as well as weekly summaries of CMP publications. Stakeholders may subscribe to these distribution lists by contacting substances@ec.gc.ca or subscribe for the latest news on the CMP.
Note that a strategy will be developed to address manufactured nanomaterials that are on the Domestic Substances List (DSL) and known to be in commerce in Canada, to determine which nanomaterials should be recommended as priorities for assessment under CEPA. The strategy will also identify which nanomaterials have knowledge gaps and needs for further research or data gathering.
Comment summary 9: The framework is comprehensive and generally aligned with current approaches and practices used for risk assessment of traditional bulk materials, while also including specific considerations to nanomaterials.
Response 9: Noted.
Comment summary 10: For bulk materials containing a small percentage of particles at the nanoscale (intentionally or incidentally), risk assessments on the bulk materials would cover the hazards and risks associated with the contained nanoparticles. This would reduce the unnecessary testing to support a nano-specific risk assessment.
Response 10: The Health Canada working definition of nanomaterials also includes particle size threshold. For example, a substance will be evaluated as a nanomaterial if it has at least 10% of its primary particle size distribution by number or at least 1% by mass of the particles in the nanoscale range (1-100 nm). These thresholds were chosen to capture intentionally manufactured nanomaterials and to exclude materials not intended to be manufactured at the nanoscale, or nanoscale particles which may be present as impurities.
Risk assessment of a non-nanoscale substance may be insufficient to cover the potential risks associated with substances of the same chemical composition at the nanoscale. This is the case where there is sufficient information of nanoscale-specific effects that change the hazard or exposure profile of a substance. For example, when compared to its bulk form, a nanoscale form of a substance could have a higher surface reactivity due to its larger surface area and could induce the formation of reactive oxidative species when exposed to ultraviolet light. The nanoscale form of a substance may be more dispersed or agglomerated, changing where in the environment it is likely to be found, and resulting in different exposure scenarios than those that would be considered for assessment of the bulk substance. Finally, due to their functional characteristics, nanoforms may have use patterns and applications that may be different than that of the bulk form.
Comment summary 11: Carbon-based nanomaterials, specifically graphene, graphene oxide and reduced graphene oxide, should be included in the list of existing nanomaterials that are in commerce in Canada.
Response 11: Any substance listed on the DSL is considered as existing in commerce in Canada. The specific terminology of ‘existing substance’ is reserved until a substance is included on the DSL. Until then, the substance is subject to the New Substances Notification Regulations (Chemicals and Polymers) (NSNR (C&P)) prior to import or manufacture in Canada. Some carbon-based nanomaterials, including certain forms of graphene, graphene-related substances, and carbon nanotubes, have been notified and assessed under the NSNR (C&P), some of which meet the criteria for addition to the DSL and are now listed there.
Comment summary 12: Currently, it seems there is no mandate to quantify the amount of a nanomaterial that exists in products. Nanomaterial concentrations (value, range, or threshold) in products should be quantified by accredited academic laboratories, research and development or commercial facilities, following established nanomaterial standards, including those for graphene-related substances, by different organizations (for example, International Organization for Standardization (ISO) Technical committee 229, ASTM International Committee E56).
Response 12: The Government of Canada’s draft framework on the risk assessment of nanomaterials reflects the guidance and policies which may be applied for the risk assessment of nanomaterials under CEPA.
Quantifying nanomaterials in products available on the Canadian market is outside the scope of this framework. Under CEPA, the concentration of nanomaterials in products is a key factor considered in risk assessment and this information is currently collected via mandatory (for example, CEPA section 71) surveys, non-mandatory follow-up, and in open literature searches. We work closely with other government programs that regulate products under different Acts and Regulations (for example, the Canada Consumer Product Safety Act, Food and Drugs Act) to validate the use or presence of nanomaterials where necessary.
Additionally, Government of Canada officials are active participants in various projects (for example, the ISO Technical Committee 229 (Nanotechnology), the OECD WPMN) and closely monitor standards and test guideline developments in nanotechnology.
Comment summary 13: The framework can establish a list of preferred Canadian-based testing facilities to carry out qualitative and quantitative nano-research.
Response 13: The framework aims to provide guidance and key considerations for the assessment of nanomaterials under CEPA. Establishing a list of testing facilities is beyond the scope of the framework and risk assessments conducted under CEPA.
Comment summary 14: The framework should be clear on how nanomaterial quantities are calculated, corroborated, and verified.
Response 14: While outside the scope of this framework, the mechanisms and approaches by which information is gathered to inform the assessment of existing and new nanomaterials under CEPA are described in section 2. In order to be considered as a nanomaterial in a CEPA risk assessment, quantities in Canada must also meet the Health Canada definition of a nanomaterial, see section 3.1.
Comment summary 15: The framework should include guidance regarding recycling and encourage manufacturers to consider recycling and to document the process of separating nanomaterials from the waste system for the purposes of recycling.
Response 15: Wherever possible, the Government of Canada takes into consideration the impact of recycling and disposal activities resulting in potential releases to the Canadian environment as part of its risk assessments of nanomaterials under CEPA. As indicated in the framework, nanomaterials in waste and their potential impacts to the environment and human health are considered as part of the exposure analysis. However, the provision of guidance on management of nanomaterial-containing waste is beyond the scope of this framework. In Canada, the responsibility for managing and reducing waste is shared among federal, provincial, territorial, and municipal governments. For more information, see Municipal solid waste: a shared responsibility - Canada.ca
Comment summary 16: In alignment with EU cosmetic regulations, the framework should include labelling of products containing nanomaterials and/or safety data sheets of nanocomposite products to better inform users.
Response 16: Labelling products containing nanomaterials and/or inclusion of this information in safety data sheets is beyond the scope of the framework.
Comment summary 17: Workplace safety recommendations on carbon nanotubes and graphene can be incorporated in the risk assessment framework, or into the Hazardous Products Regulations to guide occupational nanomaterial safety protocols.
Response 17: Assessments conducted under CEPA focus on risks of exposure of the general population, including populations who may be disproportionately impacted. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS).
The Government of Canada recognizes that it is the responsibility of the federal, provincial and territorial occupational health and safety organizations to coordinate legislation for the safe use of chemicals in the workplace. We are working to support this role by integrating the information, tools, and/or technical expertise of the CMP and Health Canada’s Workplace Hazardous Products Program.
Comment summary 18: Nanomedicine use, as one of the commercial uses, should undergo more rigorous qualitative and quantitative testing and documentation, including their environmental effects after use, upon disposal and during production.
Response 18: At Health Canada, the safety and efficacy of nanomedicines are regulated and subject to existing legislative and regulatory frameworks. Health Canada applies the Food and Drug Regulations, the Natural Health Products Regulations, and the Medical Devices Regulations under the authority of the Food and Drugs Act so that drugs, including natural health products, and medical devices that are on the Canadian market are safe and effective. Through the CMP under CEPA, the Government of Canada also assesses and manages risks to human health and the environment posed by chemical substances that can be found in food and food products, consumer products, cosmetics, drugs, drinking water and industrial releases.
Comment summary 19: A nanomaterials knowledge base should be developed to facilitate a smooth adoption of the framework and the sharing of information, including relevant standards such as testing facilities, quantifying, and characterization techniques. In parallel to the framework, nanomaterials accreditation and certification should be developed, allowing for academic research in collaboration with industry to meet nanomaterial reporting requirements.
Response 19: We recognize the importance of characterization and measurement technique development, as well as standards for informing robust scientific evaluation of nanomaterials. Regulators from Health Canada and Environment and Climate Change Canada actively participate in various projects within ISO Technical Committee 229 (Nanotechnology) and the OECD on standard and testing guideline development related to nanomaterials. However, accreditation and certification are beyond the regulatory regime of Environment and Climate Change Canada and Health Canada under CEPA.
Comment summary 20: To keep alignment between regulators and industry, clarification is needed for the role of the end-users, specific data requirements for risk assessments, and how the framework can be used by industry (for example, develop industry-specific guidelines).
Response 20: Data consideration is described in section 3.3 of the framework.
Anyone manufacturing or importing nanomaterials in or into Canada may be subject to information gathering initiatives under CEPA (for nanomaterials listed on the DSL), or data requirements under the NSNR (C&P) (for new nanomaterials). More information on data requirements for new nanomaterials can be found in the Guidance document for the New Substances Notification Regulations (Chemicals and Polymers).
The framework aims to provide regulators with guidance on the assessment of nanomaterials under CEPA and serves to inform stakeholders about the principles, approaches and key considerations used in assessing nanomaterials under CEPA. This framework is not meant to create industry-specific guidelines. Furthermore, other assessment approaches may be considered on a case-by-case basis.
Comment summary 21: Lack of specificity in the draft may result in misaligned interpretation of accountabilities, data gathering and evaluation.
Response 21: The framework reflects the guidance and policies used for the risk assessment of nanomaterials under CEPA. It provides guidance on how most risk assessments of nanomaterials are conducted under CEPA. Other assessment approaches not outlined in the framework may be considered on a case-by-case basis.
Comment summary 22: Support a unified approach for covering various exposures (for example, dermal, inhalation) and under which both human and environmental risks are considered.
Response 22: Noted.
Comment summary 23: Clarification is needed on how this framework would be enforced.
Response 23: The framework reflects the guidance and policies used by Health Canada and Environment and Climate Change Canada for the risk assessment of nanomaterials under CEPA. It provides guidance on how most risk assessments of nanomaterials are conducted under CEPA. The framework does not specify any data requirements or other obligations for stakeholders involved with nanomaterials, including enforcement. More information on data requirements for new nanomaterials can be found in the Guidance document for the New Substances Notification Regulations (Chemicals and Polymers).
Executive summary
Comment summary 24: The language regarding nanotechnology as “an emerging technology with enormous innovation potential” and “rapidly entering the Canadian market” should be changed to reflect older established nanomaterials/technologies. For instance, synthetic amorphous silica and carbon black are nano substances that have been around for decades.
Response 24: Noted. The words “emerging” and “rapidly” have been removed.
Human health effects
Comment summary 25: We support Health Canada/Environment and Climate Change Canada’s assessment in regard to considering lung overload when interpreting inhalation toxicity studies. Additional references were provided.
Response 25: Noted.
Comment summary 26: This framework should provide references for specific in vitro studies, and how these studies can be used in a regulatory context.
Response 26: Noted. Additional text has been inserted into section 3.5.2.1, providing references for specific in vitro studies that may be applicable to nanomaterials testing.
Comment summary 27: The wording regarding lung overload considerations should be revised to reflect that lung overload is an important consideration that is not unique to only nanomaterials, but also non-nanosized particle matter, particularly those with low density.
Response 27: Noted. Additional text has been added to section 3.5.2 of the framework.
Ecological effects
Comment summary 28: Regarding the statement “It is possible that more hazardous forms or more bioavailable forms of the NM are generated during manufacture, or at other stages of the life cycle of NMs”, it would be difficult for a manufacturer to foresee physical or chemical transformation undertaken by a downstream user. Modelling environmental bioavailability throughout the life cycle is challenging too.
Response 28: The framework aims to provide guidance and key considerations for the assessment of nanomaterials under CEPA, including the possibility of increased potential of risk due to nanomaterials’ transformations throughout their life cycle.
Read-across
Comment summary 29: Specific examples (for example, surface area range, particle size distributions) should be provided for the read-across approach as to what is considered “similar” in grouping nanomaterials.
Response 29: Currently there are no standard thresholds for determining similarity in read-across approaches for nanomaterials and, consequently, these are performed on a case-by-case basis for each substance. This is largely because read-across approaches for nanomaterials are based on the data availability for hazard, environmental fate, and other physical-chemical properties for another nanoform of the same chemical composition for comparison. As mentioned in section 3.3.3 of the framework, similarities in physico-chemical properties, (eco)toxicokinetics, fate and toxicological behaviour are used to establish a robust justification for any read-across approach under consideration.
When identifying a grouping strategy for substances with different nanoforms, read-across is dependent on many factors, including the size and quality of the dataset, consistency in characterization methods and media. Although clear thresholds have not been developed for determining the similarity of different nanoforms of a substance, some guidance is available, such as in section 3.3 of the ECHA (2019) guidance, which provides specific examples of how read-across may be applied in risk assessments.
Comment summary 30: Regarding the statement “read-across from the bulk material to the nanoscale form…”, it should be noted that some nanomaterials only have a nanoscale form (for example, carbon nanotubes), while other nanomaterials exist mainly as secondary forms that are outside the nanoscale.
Response 30: Noted. As stated in section 1.3 of the framework, read-across is performed on a case-by-case basis.
Comment summary 31: Similarities in physical-chemical properties is important for read-across and case-by-case material-based models should be considered.
Response 31: Noted. Also, see previous responses on the topic of “Read-across”.
Nanomaterial and/or nanoform definition
Comment summary 32: Health Canada’s working definition of nanomaterials should be updated to align with other jurisdictions. This may include providing more guidance or collaboration with industry. The 10% primary particle cut-off for the Health Canada working definition of nanomaterials should be aligned with other internationally accepted definitions, such as from the OECD, the World Health Organization and ISO (by removing the 10% primary particle cut-off), or aligned with the 50% primary particle cut-off from the EU definition.
Scientific basis of the 10% threshold also needs to be clarified, and measurement methods should be specified.
Response 32: Updating the Health Canada working definition of nanomaterials is beyond the scope of the framework.
The current Health Canada working definition of nanomaterials provides size thresholds for a particle to be considered a nanomaterial; it does not refer to thresholds for the number of nanoscale particles needed to meet the definition.
Under CEPA, a substance is evaluated as a nanomaterial if it meets the Health Canada working definition (GoC 2011) and 10% or more by number of its primary particles have at least one dimension at the nanoscale, or if at least 1% by mass of the primary particles have at least one dimension at the nanoscale. These particle size thresholds are indicated in the framework and specified in the Guidance document for the New Substances Notification Regulations (Chemicals and Polymers). These particle number thresholds are consistent with other jurisdictions and were chosen to capture intentionally manufactured nanomaterials while at the same time excluding materials not intended to be manufactured at the nanoscale, or the nanoscale particles which may be present as impurities. The 10% by number threshold aligns with the Government of Canada’s reporting requirements used in a 2015 information gathering survey for nanomaterials.
In the international context, Canada’s 1% by mass threshold is in line with the United States Environmental Protection Agency’s final rule for Toxic Substances Control Act (TSCA) reporting and recordkeeping requirements for nanoscale materials. The EU defines nanomaterials under REACH with a threshold of 50% or more by number of nanoscale particles (in contrast with Canada’s 10% threshold) and has significant data reporting requirements prescribed in annexes VI, I, III, VII-XI and XII of REACH when their threshold is met.
The Government of Canada is aware of the differences of nanomaterials definitions and is an active participant in international forums where issues such as this are being discussed, such as the OECD WPMN.
As stated in the updated Guidance document for the New Substances Notification Regulations (Chemicals and Polymers), a combination of measurement methods to determine the overall particle size distribution is recommended. The guidance on measurement methods for particle size and size distribution are further outlined in the OECD test guideline No. 125: Nanomaterial Particle Size and Size Distribution of Nanomaterials, also referenced in section 3.2 of the framework.
Comment summary 33: The language and wording regarding “nanoscale properties/phenomena” should be more cautious, as it is a hypothesis only and most nanomaterials in commerce exist as aggregated/agglomerated materials, and are very similar, if not identical, to their bulk form.
The United States Environmental Protection Agency’s wording of “unique and novel properties” is a preferable alternative as it is less ambiguous and subjective.
Response 33: Noted. Updating Health Canada’s working definition of nanomaterials is beyond the scope of the framework.
However, it is worth noting that section 4.2 of the Policy Statement on Health Canada’s working definition further elaborates by stating:
Evidence suggests that nanoscale properties/phenomena are more likely observable at the scale of 1-100 nanometres and that it is possible for nanoscale properties/phenomena to be exhibited outside this size range. Internal or surface structures at the nanoscale can include nanomaterials that are aggregated or agglomerated to form a larger group. While the break-up of aggregates is less likely, a larger group could be broken down into component nanomaterials in the human body or in the environment. It is also noted that some regulatory programs may request information above the 100 nm size range to an upper limit of 1000 nm in order maintain flexibility to assess potential nanomaterials, including suspected nanoscale properties/phenomena.
Health Canada’s working definition of nanomaterials is based on objective and measurable properties, which accommodate substances with internal or surface structures at the nanoscale (for example, aggregates/agglomerates) and nanoscale properties/phenomena and allows for reproducible interpretation by regulators or stakeholders.
Whether a nanomaterial demonstrates unique and novel properties from its bulk form may be considered for prioritizing which nanomaterials on the DSL should be identified as priorities for assessment under CEPA.
Comment summary 34: A request to update the nanomaterials definition, including possible harmonization with the United States on the definition and risk assessment approaches, was submitted to the Treasury Board Secretariat during the Regulatory Cooperation consultation period in 2022.
Response 34: Noted. Updating Health Canada’s working definition of nanomaterials is beyond the scope of the framework.
Comment summary 35: “Nanoform” should be defined, including distinguishing the differences between types of nanoform and the differences between “old” (for example, silica and carbon black) and “new” nanoforms.
Response 35: The framework elaborates on “nanoform” (sections 3.2 and 3.3), such as variations in size, shape and/or surface modifications for a given nanomaterial, which is in line with the ECHA guidance on registration of nanomaterials under REACH.
Comment summary 36: The working definition of nanomaterials should be clarified as to whether it is applicable to manufactured nanomaterials or if includes all materials including impurities and incidental particles at the nanoscale, and how this links to the percent by particle number criteria.
Response 36: Updating Health Canada’s working definition of nanomaterials is beyond the scope of the framework.
The Health Canada working definition specifies the term “manufactured” as including engineering processes and the control of matter that leads to the synthesis, generation, fabrication, or isolation of nanomaterials. The definition also indicates that information on “deliberately or incidentally” manufactured nanomaterials may be requested to inform risk assessment.
Aggregates/agglomerates
Comment summary 37: Since most nanomaterials exist as aggregate/agglomerated forms (secondary forms), they do not break down to primary particles and may not have greater ability to translocate compared to their bulk form, as supported by a study showing carbon black particles tend to be in large agglomerates in lung fluid.
Response 37: The stability of aggregates/agglomerates depends on environmental or biological conditions. The exposure to a nanomaterial may be in a deagglomerated form as a nanoscale particle. The state of the nanomaterial relies on the pattern of use and conditions (for example, pH, ionic strength) of the specific environmental or biological media.
Under CEPA, risk assessments of existing and new nanomaterials are typically conducted on a substance-by-substance basis. In the absence of data on substance characteristics (for example, aggregation/agglomeration state) under exposure or use conditions, weight of evidence and precaution approaches are used, as outlined in section 2.3 of the framework.
Data gap analysis
Comment summary 38: The sponsored literature reviews on ecotoxicity and human health indicate that nanoparticles of a particular DSL substance do not appear to be more toxic than dissolved/bulk forms of the same substance, and no new nano-specific effects were noted. This is supported by the sponsored acute oral (OECD 425) and inhalation (OECD 403) toxicity studies.
Response 38: Noted. This will be considered as part of the weight of evidence in the risk assessment of the identified DSL substance at the nanoscale.