Chemical name: 1,3,4-Metheno-1H-cyclobuta[cd]pentalene, 1,1a,2,2,3,3a,4,5,5,5a,5b,6-dodecachlorooctahydro- Final regulatory action has been taken for the category: Industrial Final regulatory action: The chemical is Severely Restricted Use or uses prohibited by the final regulatory action: The Regulations prohibit the manufacture, use, sale, offer for sale or import of mirex, with the exceptions listed below. Use or uses that remain allowed: The Regulations do not apply to the incidental presence of mirex, or for use in a laboratory for scientific research purposes or as a laboratory analytical standard. The final regulatory action was based on a risk or hazard evaluation: Yes Summary of the final regulatory action: The Prohibition of Certain Toxic Substances Regulations, 2005 prohibit the manufacture, use, sale, offer for sale and import of toxic substances listed in Schedules 1 and 2 to the Regulations. Mirex is found in Schedule 1, which lists prohibited toxic substances subject to total prohibition, with the exception of incidental presence. The reasons for the final regulatory action were relevant to: Human health and environment Summary of known hazards and risks to human health: Note: Mirex was assessed under the original Canadian Environmental Protection Act (CEPA). While the Act was updated in 1999, the conclusions of the assessment remain the same. This notification is based on the assessment and therefore references the original Act. Information provided here was current at the time of the original notification. Mirex is specified on the List of Toxic Substances in Schedule I to the Canadian Environmental Protection Act (CEPA). The assessment of substances to determine if they are "toxic" under the CEPA is a shared responsibility of Environment Canada and Health Canada. Environment Canada assesses the environmental risks, and Health Canada assesses the human health risks. An assessment was conducted to determine if a substance is likely to harm the environment or the health of humans, taking into account the likelihood and magnitude of releases at levels occurring in the Canadian environment. Thus "toxic" in the context of CEPA is a function of both the inherent properties of a substance and the amounts, concentrations, or nature of entry of the substance in the Canadian environment. The assessment process thus provides a framework for making science-based decisions on the effective management of toxic substances that are of concern. The determination of whether or not a substance is "toxic" must be based on sound, scientifically reliable data. Under CEPA, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that
The main sources of mirex in Canada were located in New York State (U.S.) in the Niagara River and the Oswego River where chemical manufacturing and fire retardant production plants were located. Canadian human exposure to mirex was generally minimal except in the group partially or wholly dependent on a diet of fish or fish-eating birds from Lake Ontario and the St. Lawrence River. A second, very small, group at risk were those hunters that occasionally ate meals of game birds. In humans, mirex is stored mainly in fat tissue, where it is not broken down. Mirex has been demonstrated to cause cancer in experimental animals and possibly carcinogenic to humans. International In response to the increasing international awareness concerning the environmental and human health risks associated with certain persistent organic pollutants (POPs) mirex was identified as one of the priority substances for consideration in the negotiation of a Protocol for POPs under the United Nations Economic Commission for Europe Convention on Long-range Transboundary Air Pollution. Due to increasing concern about the risks to human health and the environment posed by persistent organic pollutants, the United Nation Environment Program (UNEP) has initiated a process to evaluate the need to develop a global legally-binding instrument for managing these substances. At the invitation of the UNEP Governing Council the Intergovernmental Forum for Chemical Safety (IFCS) submitted a report to the Governing Council for consideration in 1997. The report concluded that there was sufficient scientific knowledge to warrant immediate international action to protect human health and the environment and to develop a global legally binding instrument to that effect.Mirex was one of the initial 12 substances to be considered under this initiative. Expected effect of the final regulatory action in relation to human health: Mirex was found to meet the criteria for Track 1 substance under Canada's Toxic Substance Management Policy and as such is to be virtually eliminated from the environment. The prohibition on manufacture, use, sale, offer for, sale, or import of mirex, will work towards the objective of virtual elimination. Summary of known hazards and risks to the environment: Note: Mirex was assessed under the original Canadian Environmental Protection Act (CEPA). While the Act was updated in 1999, the conclusions of the assessment remain the same. This notification is based on the assessment and therefore references the original Act. Information provided here was current at the time of the original notification. Mirex is specified on the List of Toxic Substances in Schedule I to the Canadian Environmental Protection Act (CEPA). The assessment of substances to determine if they are "toxic" under the CEPA is a shared responsibility of Environment Canada and Health Canada. Environment Canada assesses the environmental risks, and Health Canada assesses the human health risks. An assessment was conducted to determine if a substance is likely to harm the environment or the health of humans, taking into account the likelihood and magnitude of releases at levels occurring in the Canadian environment. Thus "toxic" in the context of CEPA is a function of both the inherent properties of a substance and the amounts, concentrations, or nature of entry of the substance in the Canadian environment. The assessment process thus provides a framework for making science-based decisions on the effective management of toxic substances that are of concern. The determination of whether or not a substance is "toxic" must be based on sound, scientifically reliable data. Under CEPA, a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that
The main sources of mirex in Canada were located in New York State (U.S.) in the Niagara River and the Oswego River where chemical manufacturing and fire retardant production plants were located. This transboundary movement of mirex into Canadian waters resulted in contamination of fish and fish-feeding birds with the results that mirex contaminated several ecosystems in Canada. Mirex is biologically active, accumulates in food chains, is extremely persistent and is dispersed in the environment. Sufficient data were not available to enable a meaningful calculation of either an acceptable or tolerable level of mirex in the Canadian environment with respect to wildlife and aquatic life. It should be noted that the U.S. EPA set the maximum concentration of mirex permissible in water for fresh water and marine aquatic life at 0.001 mg/L. This value was obtained through the use of an application factor of 0.01 times the lowest concentration at which effects have been noted in crayfish, the most sensitive species tested. Quantitative information describing the persistence of mirex was limited. However, the available information consistently indicated that the substance is persistent in the environment. For example, 12 years after its application to clay soil, 50% of the mirex originally applied was recovered as mirex and mirex-related compounds with mirex representing between 65-70% of the total residues. Mirex decomposition in the environment takes place chiefly by photolysis. Anaerobic decomposition by microorganisms can occur, but it is not extensive. Mirex is also recognized to be subject to long-range transport and has been demonstrated to persist in sediment. On the basis of the available information, it was concluded that mirex is persistent in the environment. Mirex can accumulate in living tissues. In experimental work with aquatic organisms, all species at all trophic levels have been found to accumulate this substance. Bioaccumulation factors of 15,000 and 51,000 have been observed in lake trout captured in Lake Ontario and fathead minnows. A comparison of concentrations of mirex in lake trout, a predator species, with those in smelt, a prey species, gives a ratio of 1.26, indicating that biomagnification is occurring. A biomagnification factor of 108 for mirex between its concentration in water of Lake Ontario and the St. Lawrence River and in beluga whale oil has been reported. In experimental studies with birds, mirex has been shown to accumulate, particularly in fatty tissues. A study showed that mirex fed to roosters accumulated to about 100 times the concentration in the feed in thirty-two weeks. When the roosters were given clean food the mirex residues slowly decreased. Similar studies were conducted on mammals with similar findings. On the basis of the available information, it was concluded that mirex is a bioaccumulative substance. Expected effect of the final regulatory action in relation to the environment: Mirex was found to meet the criteria for Track 1 substance under Canada's Toxic Substance Management Policy and as such is to be virtually eliminated from the environment. The prohibition on manufacture, use, sale, offer for, sale, or import of mirex, will work towards the objective of virtual elimination. Date of entry into force of the final regulatory action: 15/05/2005 |