Summary of Public Comments received on the draft screening assessment for rapid screening of substances identified during Phase Two of the Domestic Substances List Inventory Update.
A summary of comments and responses is included below organized by topic:
| Topic | Comment | Response |
|---|---|---|
| Methodology | Not all substances inherently have characteristics that lend themselves to down-the-drain applications. A mechanical screen, using professional judgement, should be implemented to establish whether it is reasonable that the substance could be used in a down-the-drain application. | The down-the-drain scenario is used as a worst-case scenario. During rapid screening exposure scenarios are consistently applied. The detailed substance-specific evaluation being proposed would be suitable for the screening assessment stage. |
| Methodology | The addition of a hazard screen similar to that used in polymer rapid screening could be beneficial because the human health component is only based on exposure potential. Specifically, it identifies if the substance is present in a product used by Canadians and if it can leach or migrate out of the final product. If the substance does not overtly represent an unacceptable hazard, there is a minimal risk and the substance could be identified as requiring no further action. | An approach for defining low hazard as part of a Rapid Screening Initiative has not been developed at this time for the non-polymeric substances. Substances determined to require further assessment through this rapid screening approach will have their hazard potential evaluated in future assessments. |
| Methodology | Appendix A provides a listing of the mechanical filters used to identify if a substance has hazardous properties or an elevated exposure potential. It should be noted that not all of these filters were constructed for this purpose and that some require caution in their use. | The context and type of information in all sources listed in appendix A have been evaluated. Substances identified by the mechanical filters may be further evaluated manually within rapid screening in order to account for the nature and purpose of the information source. |
| Information and data gaps | The acute toxicity from categorization (iT pivotal value) should be disclosed in the assessment, possibly in an appendix. | Results of categorization, including pivotal iT values, are available on Environment Canada’s website. Reference to this source has been included in the ecological approach section of the Screening Assessment Report. |
| Information and data gaps | Describe or identify "other resources" used for determining the potential for direct exposure for the human health component in the Approach discussion on page 17. | For each substance, general literature searches, including a web-based search, were conducted on publically available information. |
| Information and data gaps | The discussion in Assessment results/Assessment of potential to cause harm to human health is sparse and should be revised to parallel that for ecological assessment. Add to this discussion a figure (similar to figure 5) that outlines the number of substances and the decisions at each human health point because it would help build understanding and assist in addressing various questions. | All steps involved in determining the potential for human exposure were considered as shown in the related flow chart. Information similar to that in figure 5 is not available, but this will be considered in future assessments. |
| Risk characterization | Clarify the phrase “in commerce” in the approach section under Ecological component (possible outcomes from Step1), because it is not apparent if “any quantity” constitutes being in commerce or if “zero” is the only value for not in commerce. | The assessment was revised to identify “in commerce” as including those above the Domestic Substance List Inventory Update (DSLIU) reporting threshold of 100 kg, as well as other substances for which quantities below 100 kg were reported. |
| Exposure potential | The protocol for migration in the human health exposure approach assumes that migration occurs even though data are not known, and advances the substance for further consideration. This assumption is overly conservative because there are very few credible public data and information to support it. | Screening assessments adhere to a precautionary approach to be conservative in the event of uncertainties. The rapid screening approach applies screening criteria to identify substances that could be harmful to human or environmental health to determine if further assessment is required. To be conservative, if information on migration was not readily available it is assumed that a potential may exist for the substance to migrate as part of these uses. A more in-depth evaluation of migration potential is outside the scope of this assessment; but will be considered for those substances where the rapid screening approach determines that further assessment is required. |
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