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ARCHIVED - Draft Screening Assessment of Hexabromocyclododecane (HBCD)

Introduction

This screening assessment was conducted pursuant to section 74 of the Canadian Environmental Protection Act,1999 (CEPA 1999) ( Canada 1999). This section of the Act requires that the Minister of the Environment and the Minister of Health conduct screening assessments of substances that satisfy the the categorization criteria set out in section 73 of the Act, in order to determine whether they meet or may meet the criteria set out in section 64 of the Act.

Based on the information obtained through the categorization process, the Ministers identified a number of substances as high priorities for action. These include substances that:

  • met all of the ecological categorization criteria, including persistence (P), bioaccumulation potential (B) and inherent toxicity to aquatic organisms (iT), and were believed to be in commerce; and/or
  • met the categorization criteria for greatest potential for exposure (GPE) or presented an intermediate potential for exposure (IPE) and had been identified as posing a high hazard to human health based on classifications by other national or international agencies for carcinogenicity, genotoxicity, developmental toxicity or reproductive toxicity.

The brominated flame retardant Cyclododecane, 1,2,5,6,9,10-hexabromo (hexabromocyclododecane; HBCD; CAS RN 3194-55-6) was identified in a pilot project list of 123 substances for screening assessment under CEPA 1999, based on chemical attributes which suggest it may be persistent, bioaccumulative and inherently toxic to non-human organisms. It was subsequently confirmed to meet these categorization criteria.

Although HBCD was determined to be a high priority for assessment with respect to the environment, it did not meet the criteria for GPE or IPE and high hazard to human health based on classifications by other national or international agencies for carcinogenicity, genotoxicity, developmental toxicity or reproductive toxicity. Therefore, this assessment focuses principally on information relevant to the evaluation of ecological risks. 

Screening assessments focus on information critical to determining whether a substance meets the criteria as set out in section 64 of CEPA 1999. Screening assessments examine scientific information and develop conclusions by incorporating a weight-of-evidence approach and precaution.

This draft screening assessment includes consideration of information on chemical properties, hazards, uses and exposure. Data relevant to the screening assessment of this substance were identified in original literature, review and assessment documents, stakeholder research reports and from recent literature searches.  For the ecological assessement, information obtained as of March 2009 was considered for inclusion in this document, and literature searches up to January 2010 were considered for the human health assessment. Key studies were critically evaluated; modelling results may have been used to reach conclusions.  In addition, an industry survey on HBCD was conducted in 2000 through a Canada Gazette notice issued under section 71 of CEPA 1999. This survey collected data on the Canadian manufacture, import, uses and releases of HBCD (Environment Canada 2001).

Evaluation of risk to human health involves consideration of data relevant to estimation of exposure (non-occupational) of the general population, as well as information on health hazards (based principally on the weight-of-evidence assessments of other agencies that were used for prioritizing the substance). Decisions for human health are based on the nature of the critical effect and/or margins between conservative effect levels and estimates of exposure, taking into account confidence in the completeness of the indentified databases on both exposure and effects, within a screening context. [1] The screening assessment does not represent an exhaustive or critical review of all available data. Rather, it presents a summary of the critical information upon which the conclusion is based.

This draft screening assessment was prepared by staff in the Existing Substances Programs at Health Canada and Environment Canada and incorporates input from other programs within these departments. The ecological component of this assessment has undergone external written scientific peer review/consultation, and comments received were considered in the production of this report. Comments on the technical portions relevant to human health were received from Toxicology, Excellence for Risk Assessment. Although external comments were taken into consideration, the content and conclusions of the screening risk assessment remain the responsibility of Health Canada and Environment Canada.

The critical information and considerations upon which this assessment is based are summarized below.


1A determination of whether one or more of the criteria of section 64 are met is based upon an assessment of potential risks to the environment and/or to human health associated with exposures in the general environment. For humans, this includes, but is not limited to, exposures from ambient and indoor air, drinking water, foodstuffs, and the use of consumer products. A conclusion under CEPA 1999 on the substances in the Chemicals Management Plan (CMP) is not relevant to, nor does it preclude, an assessment against the hazard criteria specified in the Controlled Products Regulations, which is part of the regulatory framework for the Workplace Hazardous Materials Information System (WHMIS) for products intended for workplace use.

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