Chemicals Management Plan Challenge Advisory Panel Summary Report
August 26-27, 2010 Meeting
Panel members present: Dr. Ted Boadway (Chair), Dr. Conrad Brunk, Dr. Nicola Cherry, Dr. John Eyles, Dr. Scott Findlay, Mr. Geoff Granville, Dr. Steve Maguire, Dr. Peter Orris.
Regrets: Dr. Jack Bend, Ms. Linda Lusby, Dr. Gina Muckle, Dr. Dayna Scott.
The Challenge Advisory Panel meeting agenda for August 27, 2010, was structured around an overview of Draft Screening Assessment Reports for Batch 11 substances. Government officials presented and answered questions related to the Batch 11 assessments.
At the Panel's request, a half-day pre-meeting session was held during the afternoon of August 26, 2010. The purpose of this half-day session was a general discussion of topics of interest that had been identified by the Panel.
August 26, 2010
The purpose of the half-day session on August 26, 2010, was for Panel members to discuss perspectives on potential approaches for cancer human health risk assessment moving forward under the Chemicals Management Plan. This was followed by a general Panel discussion.
August 27, 2010
The meeting began with a scheduled in camera session for Panel members. Government officials were invited to attend following the in camera session.
Welcome and Introductory Comments:
The Chair welcomed all members and government staff. The meeting was opened with introductory remarks from the Chair and a report from the Panel's in camera session.
The Chair noted the mandate of the Panel would be coming to an end following release of the final Batch of screening assessments for substances included in the Chemicals Management Plan Challenge. The Panel reported that they would be interested in participating in a final meeting, to be held in February or March 2011. This would provide an opportunity for Panel members to retrospectively provide feedback to the Government following the end of their tenure. Government officials indicated they would look into setting up such a meeting.
The Panel further indicated that the discussion of sensitization, which had been identified by the Panel as a topic of interest for possible future discussions, should be scheduled for this final meeting. The meeting planned for December 2010 would focus exclusively on the assessment of substances in Batch 12 of the Challenge.
Following the Chair's report, senior government officials provided opening remarks. Government officials provided a report on the status of Notices of Objection filed under the Challenge. Pertaining to Notices of Objection, government officials indicated that responses to all Notices filed to date for substances in the Challenge substances had been posted to the CEPA Environmental Registry Website. Panel members were informed that, in response to one of the Notices of Objection, a Board of Review had been established by the Minister of the Environment to inquire into the nature and extent of the danger posed by siloxane D5, a substance in Batch 2 of the Challenge.
An update on assessment activity for substances in the Challenge was also provided to the Panel. Government officials noted that updated draft screening assessment reports for four substances in Batch 6 of the Challenge and one substance in Batch 8 would be published on October 2, 2010, at the same time as draft assessments for Batch 11. For these substances, information arising following publication of initial draft assessments for these substances has been incorporated into the updated assessments.
Panel Discussion on Batch 11 Draft Screening Assessment Reports:
Government staff presented an overview of Draft Screening Assessment Reports for Batch 11 substances.
Topics of discussion raised by Panel members included the following:
- One Panel member asked whether a substance could be proposed harmful to human health under the Challenge if only a small proportion of the general population were exposed to levels of concern. Government officials indicated that this could occur and provided some examples from the Challenge.
- For substances for which health effects information on analogues and outputs from quantitative structure-activity relationships (QSAR) modelling were used to inform human health risk characterization, Panel members suggested that justifications for choice of analogue could be strengthened in the draft screening assessment reports.
- One Panel member questioned whether it is possible to conclude that it remains uncertain whether or not a chemical substance is harmful to human health or the environment under the Canadian Environmental Protection Act, 1999 (CEPA 1999). Government officials noted that the option exists in CEPA 1999 to conduct further assessment through the Priority Substances List (PSL) process in such situations. For Challenge screening assessment reports, the uncertainties sections of the reports outline the key uncertainties and level of confidence in the risk characterization for the substance being assessed.
- For the substance PREPOD (CAS No. 68412-48-6), one Panel member suggested adding further information on uses of the substance and concentrations of the substance in certain products. It was further noted that the rationale behind the decision to use modelled toxicity data in the ecological assessment could be strengthened in the draft assessment.
- Panel members asked about the potential for the general population to be exposed to the substances BENPAT/BENTAX (CAS Nos. 68953-84-4 and 68478-45-5) through tire particles released from road wear and from the use of recycled or reused rubber products.
- The Panel suggested specific clarifications to the language within the human health risk characterization for the substance MHDnMH (CAS No. 70900-21-9).
- For the silicone MVTFS (CAS No. 68952-02-3), one Panel member noted that the ecological assessment was based almost entirely on modelled or analogue data, and commented that this must result in a high degree of uncertainty in the conclusion for MVTFS. This was discussed by Panel members and government officials. It was clarified that because the analogue substances were also silicones and the group tends to behave similarly, that in fact there was a high level of confidence in the ecological conclusion for MVTFS.
- For the substance DEHA (CAS No. 103-23-1), the Panel asked whether any of the cosmetics or personal care products containing DEHA were intended for use on children. Government officials indicated that no products were intended for use on children, and that this would be clarified within the screening assessment. One member of the Panel indicated that the discussion on chronic toxicity within the ecological assessment for this substance could be strengthened.
- The Panel asked how the Government determines whether margins of exposure are considered adequate. They further noted that specifying target margins of exposure would increase transparency. Government officials noted that the approach taken to determine whether margins are adequate is consistent with the approach used by Health Canada's Pest Management Regulatory Agency in the Science Policy Note: The Application of Uncertainty Factors and the Pest Control Products Act Factor in the Human Health Risk Assessment of Pesticides.
- There was a discussion by the Panel pertaining to the naturally-occurring presence of furfural (CAS No. 98-01-01) in foods. One Panel member noted that although the approach for exposure and risk characterization from naturally-occurring sources of substances has been consistent in the Challenge, he saw merit in presenting margins of exposure from naturally-occurring sources. This would facilitate an understanding of the relative contributions of exposure from naturally-occurring sources and incremental exposures from other sources
- For the substance ethyl acrylate (CAS No. 140-88-5), Panel members suggested clarifications of language within the human health risk characterization pertaining to the sensitization endpoint. With respect to that endpoint, one Panel member noted the use of this substance in personal wipes intended for use on infants. The Panel reiterated their interest in participating in a future discussion of how best to address the sensitization endpoint in screening assessments.
- For the substance ethanedial (CAS No. 107-22-2), Panel members suggested clarifying within the report whether dermal exposure estimates pertained to dermal deposition or systemic exposure. Government officials indicated this comment would be addressed in the screening assessment.
- One member of the Panel asked for clarification regarding the term
"conservative" in Challenge ecological assessments. Government officials clarified that in this context, the term
"conservative" was intended to mean protective of the environment, and that the potential ambiguity of this term would be kept in mind when drafting future assessments.
- During the course of the meeting, Panel members suggested a number of potential groupings of substances that could be considered for future group assessments under the Chemicals Management Plan.
Overall, the Panel considered that weight of evidence and precaution were applied appropriately in the Batch 11 draft screening assessment reports.