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Response to Comments on Proposed Risk Management Approach for Polychlorinated Naphthalenes (PCNs)
The risk management approach for PCNs was posted on Environment Canada’s Website on July 2, 2011 for a 60-day public comment period.
Comments on the proposed risk management approach document for PCNs to be addressed as part of the Chemicals Management Plan were provided by an industry stakeholder.
A summary of comments and responses is included below, organized by topic.
- Substance Information
- Characterization of Risk
- Unintentional Production and Releases to the Environment
- Presence in the Canadian Environment
- Existing Risk Management
- Socio-economic Considerations
- Environmental Objective
- Risk Management Objective
- Proposed Risk Management
|The Government of Canada should clearly identify CAS number associated with PCNs. Not identifying CAS numbers could cause difficulties for government and/or the regulated community in the future.||PCNs are described as C10H8-nCln (where n>1) in the Order adding these substances to Schedule 1 of the Canadian Environmental Protection Act, 1999. This description correctly represents the substances determined to be harmful to the environment as per paragraph 64(a) of the Act. It may not be possible to list the CAS Registry Numbers in regulations for the following reasons: not all substances have a CAS number, it can be difficult to identify an exhaustive list of CAS numbers, and CAS numbers may change over time. For these reasons, the Government of Canada does not list CAS numbers in the regulations. For example the Polybrominated Diphenyl Ethers Regulations and Perfluorooctane Sulfonate and its Salts and Certain Other Compounds Regulations do not list CAS Registry Numbers. However, a non-exhaustive list of known CAS Registry Numbers is provided as part of the guidance materials.|
Characterization of Risk
|The Government of Canada should confirm if PCNs are present in the environment in sufficient quantities to cause exposure and in turn to create unacceptable risk before taking risk management actions.|
Conducted pursuant to CEPA 1999 section 74, the screening assessment concluded that di- to octa-CNs (i.e. PCNs with the molecular formulaC10H8-nCln (where n>1)) are toxic under CEPA 1999, i.e. that they are entering or may enter the environment in a quantity or concentration, or under conditions that have or may have immediate or long-term harmful effects on the environment or its biological diversity. 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, magnesium production, and the refining of metals such as aluminium. This is supported by several studies, referenced in the final SAR, that present monitoring data which confirm the presence of CNs in releases from a number of these facilities, including municipal waste incinerators.
Even though PCNs are no longer used in Canada, PCNs continue to be detected in a variety of environmental samples over wide areas of Canada because of their historical use and continued incidental releases.
Based on the above and other lines of evidence presented in the screening assessment, particularly the evidence for persistence, bioaccumulation and potential to cause both acute and chronic harm at low exposure values, it was concluded that PCNs have the potential to cause environmental harm in Canada.
Any available monitoring data will continue to be considered to determine if additional risk management measures are necessary.
Unintentional Production and Releases to the Environment
|The Government of Canada should publish and peer review any available information on unintentional releases of PCNs.||A study was undertaken to better characterize unintentional production of PCNs. The study has demonstrated that there is a correlation between releases of PCNs and dioxins and furans. As a result, control measures in place for dioxins and furans are expected to also control PCNs. As a consequence no additional control measures are proposed at this time for the control of the unintentional releases of PCNs.|
Furthermore, monitoring of PCNs is occurring under a comprehensive monitoring and surveillance strategy under the Chemicals Management Plan. This monitoring will be used to determine whether further action needs to be taken with respect to unintentional releases of PCNs in the future.
|Given the analogous nature of PCNs and dioxins and furans, the Government of Canada should give consideration to the actions already in place to control dioxins and furans when considering actions targeting unintentional production and release of PCNs.|
|PCNs will likely be produced from natural combustion similar to dioxins and furans. Furthermore, natural source of PCNs will likely outweigh any man made sources. Consequently, the Government of Canada should take into consideration natural sources in developing any risk management actions.|
Presence in the Canadian Environment
|The Government of Canada should confirm the sources of PCN releases before taking any risk management action to ensure the source generating unacceptable risk is being addressed and the concentrations in the environment are truly high.||PCNs are persistent and bioaccumulative substances, therefore there is a potential for an increase in their presence in the Canadian environment in the future, if they are not properly managed. As a consequence, the Government of Canada has proposed PCNs for addition to the Prohibition of Certain Toxic Substances Regulations, 2012. These regulations would prohibit the manufacture, use, sale, offer for sale or import of PCNs or any product containing PCNs.|
In addition, the monitoring data from the comprehensive monitoring and surveillance strategy under the Chemicals Management Plan will be used to determine whether further action needs to be taken with respect to PCNs.
Existing Risk Management
|It is surprising that there is a statement indicating over 90% compliance with the Pulp and Paper Mill Effluent Chlorinated Dioxins and Furans Regulations and the Pulp and Paper Defoamer and Wood Chip Regulations.||Compliance can be assessed by comparing the total number of inspections from 2008-09 to 2010-11 to the total number of enforcement measures taken in response to violations. During this period, 272 inspections were conducted under the Pulp and Paper Mill Effluent Chlorinated Dioxins and Furans Regulations and 137 inspections were conducted under Pulp and Paper Defoamer and Wood Chip Regulations. None required enforcement measures to be taken.|
For more information, please see CEPA Annual reports Archives.
|Citation or reference supporting the statement “reports indicate PCNs have been detected in cement kiln dust” should be provided.||More detailed information on PCNs detected in cement kiln dust is provided in the Final Risk Assessment for PCNs. This report includes a number of supporting references including:|
Helm PA, Bidleman TF. 2003. Current combustion-related sources contribute to polychlorinated naphthalene and dioxin-like polychlorinated biphenyl levels and profiles in air in Toronto, Canada. Environ Sci Technol 37:1075–1082.
|There are still chlor-alkali facilities operating in Canada in contrast of what was stated in section 6.1 of the Risk Management Approach.||There are still chlor-alkali plants in Canada but none of these are mercury cell chlor alkali. The unintentional releases of PCNs have only been associated with the use of graphite anodes in mercury cell chlor alkali plants. When mercury cell plants were operating in Canada, graphite anodes were used. The graphite anodes would "breakdown" in the cell and form several chlorinated organic compounds including PCN. The last mercury cell chlor alkali plant was shutdown in June 2008.|
|The Government of Canada should consider the socio-economic factors in the selection of the instruments. If so, the Government of Canada should disclose the details of risk management instrument analysis and selection.||Socio-economic factors were taken into consideration when recommending the addition of PCNs to the Prohibition of Certain Toxic Substances Regulations, 2012. Information on socio-economic considerations and options considered can be found in the Regulatory Impact Analysis Statement that was published along with the regulations in Canada Gazette Part II.|
|How the Government of Canada will consider the social and economic aspect of the proposed control measures for PCNs?|
|Since the ultimate environmental objective for PCNs is virtual elimination, the Government of Canada should develop the Level of Quantification in a fully transparent manner and should follow the requirements under CEPA 1999.||PCNs have been added to the Prohibition of Certain Toxic Substances Regulations, 2012. These regulations prohibit the manufacture, use, sale, offer for sale or import of PCNs or any product containing PCNs. Regarding unintentional production and release of PCNs, there are a number of existing measures that are believed to address expected these sources. Furthermore, monitoring of PCNs is occurring under a comprehensive monitoring and surveillance strategy under the Chemicals Management Plan. These actions work towards the goal of virtual elimination over time.|
Risk Management Objective
|The principle of action to prevent reintroduction of PCNs into Canada is supported. The concept of an instrument considering what is technically and economically feasible is also supported. Any action should be affordable and deliver real improvement in the environment or with human health.||PCNs were added to the Prohibition of Certain Toxic Substances Regulations, 2012. These regulations would prohibit the manufacture, use, sale, offer for sale or import of PCNs or any product containing PCNs. Given that PCNs have not been in commerce for more than 2 decades and substitutes are already in use, minimal costs are expected to be incurred as a result of the proposed regulatory requirements for PCNs.|
Proposed Risk Management
|The Government of Canada should not prematurely publish proposed regulations for PCNs before the completion of the consultation process for the Risk Management Approach and the addition of PCNs to Schedule 1 of CEPA 1999. However they noted that in principle they supported regulations prohibiting PCNs.||The Government of Canada published a Risk Management Scope for PCNs which stated that a prohibition was being considered. No comments were received regarding the proposal to prohibit these substances. In addition, stakeholders had an opportunity to provide comments on the proposed regulatory controls for PCNs when the proposed Prohibition of Certain Toxic Substances Regulations, 2012 were published in Canada Gazette on July 23, 2011 for a 75-day public comment period. Comments received on the proposed regulations suggested that stakeholders were supportive of the proposed regulatory measures for PCNs.|
|Section 9.1 of the Proposed Risk Management identifies the Prohibition of Certain Toxic Substances Regulation as a potential instrument for control action on PCNs. The Government of Canada should inform and allow the stakeholder community to review action items.|
|The Government of Canada should not disrupt the products already in use that contain PCNs, such as underground cables.||The Prohibition of Certain Toxic Substances Regulations, 2012 take into consideration any potential issues associated with existing products containing PCNs.|
|The supply of PCNs as standards for analytical purposes should be allow as it would benefit the industry and promote research.||The Prohibition of Certain Toxic Substances Regulations, 2012 take into consideration the use of PCNs as analytical standards.|
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