Summary of Public Comments received on the Challenge substance Quartz and Cristobalite Draft Screening Assessment Report and Risk Management Scope Document for Batch 12

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Comments on the draft screening assessment report for Quartz and Cristobalite to be addressed as part of the Chemicals Management Plan Challenge were provided by Industrial Minerals Association-North America, Organisation for Economic Co-operation and Development (OECD) High Production Volume (HPV) Chemicals Programme, Target Products Ltd, a Concerned Citizen, Omya Inc and the Cement Association of Canada.

A summary of comments and responses is included below, organized by topic:

Precautionary PrincipleConsistent with the precepts of the precautionary principle, Environment Canada and Health Canada followed an approach to assessing concentrations of respirable quartz and cristobalite in the ambient air that was even more conservative than the agencies may fully appreciate.The application of precautionary principle is consistent with the approach taken throughout the Ministerial Challenge.

Inherent Toxicity


The assessment does not adequately describe the occupational risk of quartz and cristobalite.Information developed through the Chemicals Management Plan process may be used to inform decisions regarding additional actions to minimize exposure to workers.
The draft screening assessment lists a variety of effects other than silicosis/fibrosis/cancer that can be associated with quartz and cristabolite (e.g., bronchitis, renal).  However, these effects are not discussed.A statement has been added in the Screening assessment to explain that the limitations from the data do not allow further quantification of the risk. Also, consistent with other screening assessment, the discussion was limited to the most critical effect.
UsesAdditional information on the proportion of quartz and cristobalite in fly ash used in concrete and a definition of ball and tube mills should be provided.Fly-ash may contain 4-14% quartz and 0.5-1% cristobalite. Ball and tube mills are types of pulverizers.  This information has been added to the Screening Assessment.
Risk Assessment ConclusionThe assessment was conducted (sources, exposure, threshold approach for the toxicity data) in a satisfactory way and the conclusion is justified.Thank you for your comment. The Government of Canada takes pride in ensuring the best science is applied to the benefit of the population.

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