Chemical name: Naphthalene, chloro derivatives

Final regulatory action has been taken for the category: Industrial

Final regulatory action: The chemical is Banned

Use or uses prohibited by the final regulatory action:

All manufacture, use, sale, offer for sale or import , or a product containing them, is prohibited unless the toxic substance is incidentally present.

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

A person must not manufacture, use, sell, offer for sale or import polychlorinated naphthalenes or a product containing them unless the toxic substance is incidentally present.

A person may use, sell, or offer for sale a product containing polychlorinated naphthalenes if the product is manufactured or imported before the day on which these Regulations come into force (March 14, 2013).

The prohibition on manufacture, use, sale, offer for sale or import of any toxic substances or products containing them does not apply if they are to be used in laboratory for analysis, in scientific research or as a laboratory analytical standard.

The reasons for the final regulatory action were relevant to: Environment

Summary of known hazards and risks to the environment:

The approach taken in the ecological screening assessment was to examine various pieces of scientific and technical information, and to develop conclusions based on a weight-of-evidence approach and using precaution as required under the Canadian Environmental Protection Act, 1999 (CEPA 1999). Since there are unique concerns about di- through octa-CNs, because they are persistent and bioaccumulative substances, the potential for these homologue groups to cause environmental harm has been evaluated separately from that of mono-CNs.

Based on the weight of evidence, including in particular measured log K_ow values for di- to octa-CNs, the measured Bioconcentration Factor (BCF) values for di-to penta-CNs in fish, and taking into account the supporting information on measured Biomagnification Factors (BMFs) for tetra- to hepta-CNs, the high dietary uptake efficiencies of hexa- to octa-CNs in northern pike, and the very slow elimination of hexa-CNs from the bodies of rats and humans, it is concluded that di- to octa-CNs are also bioaccumulative.

There are special concerns about persistent and bioaccumulative substances that are also potentially harmful to organisms at low concentrations in controlled toxicity tests.

Although current science is unable to accurately predict the ecological effects of these substances, they are generally acknowledged to be highly hazardous. Assessments of such substances may thus be performed using a more conservative (precautionary) approach.

Evidence that a substance is highly persistent and bioaccumulative, as defined in the Persistence and Bioaccumulation Regulations of the Canadian Environmental Protection Act, 1999 (CEPA 1999), when taken together with potential for environmental release or formation and potential for toxicity to organisms, provides a significant indication that it may be entering the environment under conditions that may have harmful long-term ecological effects. Substances that are persistent remain in the environment for a long time after being released, increasing the potential magnitude and duration of exposure. Substances that have long half-lives in mobile media (air and water) and partition into these media in significant proportions have the potential to cause widespread contamination. Releases of small amounts of bioaccumulative substances may lead to high internal concentrations in exposed organisms. Highly bioaccumulative and persistent substances are of special concern, since they may biomagnify in food webs, resulting in very high internal exposures, especially for top predators.

The available empirical and modelled aquatic toxicity data for CNs indicate that di-, tri-, tetra- and penta-CNs may be harmful to aquatic organisms at relatively low concentrations: less than 1 mg/L for acute exposures, and less than 0.1 mg/L for chronic exposures. Hexa-, hepta- and octa-CNs were found to cause harmful effects to mammals (particularly cattle) at relatively low doses of 2.4 mg/kg body weight per day and less.

Beginning around 1910, mono- to octa-CNs were produced commercially as Halowax mixtures for a variety of uses. Although CNs are not currently in commercial use in Canada, CNs may be produced unintentionally as a by-product of industrial processes involving heat and/or chlorine, such as waste incineration, cement and magnesium production, and the refining of metals such as aluminium.

Even though CNs are no longer used in Canada, because of their historical use and continued incidental releases, CNs continue to be detected in a variety of environmental samples over wide areas of Canada. For example, they have been detected in Arctic and urban air, in water from Lake Ontario, in fish and birds from the Great Lakes and environs, in seals and whales from the Canadian Arctic, and in Vancouver Island marmot. Their widespread presence in biota demonstrates that uptake and bioaccumulation are occurring and therefore there is the potential for adverse effects.

Finally, there is international consensus on the concerns posed by CNs and the need for coordinated international action due to their long-range transport in the atmosphere.

Based on the lines of evidence presented above, particularly the evidence for persistence, bioaccumulation and potential to cause both acute and chronic harm at low exposure values in controlled toxicity tests, and taking into account the limitations of existing quantitative risk estimation methods when applied to such substances, and recognizing that, although CNs are no longer in commercial use in Canada, they continue to enter the Canadian environment from unintentional production as well as transboundary movement of air, and have been identified as a concern by international consensus, it is concluded that di- through octa-CNs have the potential to cause environmental harm in Canada.

Expected effect of the final regulatory action in relation to the environment:

Prevention of potential risks of harm to the Canadian environment by prohibiting the manufacture, use, sale, offer for sale or import of PCNs as well as products containing these substances with a limited number of exemptions.

Date of entry into force of the final regulatory action: 14/03/2013