Summary of public comments received on the draft assessment for the Titanium-containing Substances Group
Comments on the draft assessment for the Titanium-containing Substances Group, assessed under the Chemicals Management Plan (CMP), were submitted by the American Chemistry Council (Titanium Dioxide Stewardship Council), Canadian Consumer Specialty Products Association and an individual.
Summarized public comments and responses are provided below, organized by topic:
Conclusion
Comment summary 1: Stakeholders are supportive of the proposed conclusion and follow-up activities.
Response 1: Noted.
General comments
Comment summary 2: A member of the public is concerned about the lab-based animal studies referred to in the draft assessment. They urge the Government of Canada to consider alternative research methodologies.
Response 2: No toxicity studies were commissioned by the Government of Canada for the purposes of this assessment.
The Government of Canada is committed to advancing efforts to replace, reduce, or refine the use of vertebrate animals in toxicity testing where possible, including through recent amendments to the Canadian Environmental Protection Act, 1999 under the Strengthening Environmental Protection for a Healthier Canada Act. As part of the Plan of Priorities, Health Canada and Environment and Climate Change Canada (ECCC) have developed a strategy to guide a path to replace, reduce or refine the use of vertebrate animals for toxicity testing and to inform assessments under CEPA.
The best available and most relevant scientific information from Canada, other jurisdictions, and academic literature, are highlighted in the assessment. To the extent that it was available, information from alternatives to vertebrate animal testing, such as kinetic modeling, human biomonitoring data and in vitro data, was considered when assessing the potential human health and environmental harm of the 13 Titanium-containing substances.
Risk assessment
Comment summary 3: The draft assessment makes no reference to the natural background of titanium, which is occasionally measured in environmental samples and, when available, should be considered when deriving predicted environmental concentrations (PECs).
Response 3: This assessment uses the ecological risk characterization information from the Ecological Risk Classification of Inorganics (ERC-I) (ECCC 2020). Background concentrations were not used in predicted environmental concentration (PEC) modelling for ERC-I (Kilgour & Associates Ltd. 2016, Appendix B of ERC-I document (ECCC 2020)). However, titanium predicted no-effect concentrations derived for ERC-I were well above background concentrations (section 4.2.1). As such, risk quotients would have been minimally sensitive to the absence of background concentrations in PEC modelling. This explanation has been added to the assessment.
Comment summary 4: Stakeholders are supportive of the approach used to estimate human exposure to titanium dioxide via food and inhalation.
Response 4: Noted.
Comment summary 5: Stakeholders are supportive of the approach used to estimate intake of titanium from country foods. They agree that the consideration of potentially susceptible subpopulations is clear in approach and interpretation.
Response 5: Noted.
References
[ECCC] Environment and Climate Change Canada. 2018. Science Approach Document: Ecological Risk Classification of Inorganic Substances. Gatineau (QC): Government of Canada.