Summary of public comments received on the risk management approach and proposed schedule 1 order for selenium and its compounds
Comments on the Risk Management Approach (RMA) and the Regulatory Impact Analysis Statement (RIAS) for the Proposed Order to add selenium and its compounds to Schedule 1 to the Canadian Environmental Protection Act, 1999 (CEPA) were provided by the NutriStart Vitamin Company, the Canadian Network for Human Health and the Environment, the Saskatchewan Environmental Society, Hallelujah Acres Diet, Real Organics & Naturals House, Cameco Corporation, the Mining Association of Canada, and the North American Metals Council.
A summary of comments and responses is included below, organized by topic:
1. New information and data
| Summarized Comment | Summarized Response |
|---|---|
| Health Canada should increase research on selenium, looking for signs of selenosis in populations with high selenium intake. | In the Risk Management Approach (RMA) elevated selenium exposures were not identified in the general Canadian population, including children, or in First Nations populations living on reserve, south of the 60th parallel (based on blood measurements). However, the Screening Assessment for Selenium and its Compounds states that further research to look for evidence of selenosis or neurotoxicity in highly exposed Canadian populations (Inuit and subsistence fishers) would reduce uncertainty in the human health assessment. Canada’s Northern Contaminants Program also continues to consider research needs for selenium. |
| There is some inconsistency in the summary with regard to data gaps for base metal smelters and refineries. | The Government of Canada requests available data on effluent at discharge points, including volumes and concentrations of total selenium in the effluent and in the environment. This includes data that is collected upstream and downstream from discharge points for base metal smelters and refineries that are not reporting to the Metal and Diamond Mining Effluent Regulations (MDMER) under the Fisheries Act. |
| The selenium fish tissue summary does not provide an accurate representation of metal mines because of the inclusion of data from decommissioned mines. | The screening assessment uses the most recent available data to characterize fish tissue concentrations related to the sector. It is therefore not exclusive to active facilities at a given point in time. |
| The public supports the addition of selenium to Schedule 1 to CEPA. However, the description of the adverse human health effects of selenosis in the RMA should be revised as it differs from the usual list of effects and from the information in the screening assessment report (SAR) for selenium and its compounds. | Additional information submitted was considered and the RMA was revised. |
| The fact that selenium is also essential to aquatic life and wildlife, and not only human health, should be included in the Regulatory Impact Analysis Statement (RIAS). | The Ecological Assessment section in the RIAS opens with the following statement: “Selenium is an essential micronutrient taken up by aquatic, soil- and sediment-dwelling organisms, through diet and direct contact with the environment.” |
| A reference to a guideline document is missing. | The RMA was revised to include the reference. |
| Selenium testing under the MDMER is not currently required. | Monitoring selenium is now required under the revised MDMER, which were published in the Canada Gazette, Part II, on May 30, 2018. |
| It is not clear whether amphibians are generally sensitive to selenium exposure. Massé AJ et al. (2015) observed developmental abnormalities in the African clawed frog, but not at the level of reproductive failure and not in field situations. | Massé AJ et al. (2016) document further studies into later stages of African clawed frog development. Additional literature on the effects of selenium on amphibians such as Janz D et al. 2014, Lockard L et al. 2013, and Metts BS et al. 2012 also suggest including amphibians in the list of egg-laying vertebrates sensitive to selenium. Massé AJ et al. (2017) further suggest that the African clawed frog is a resilient species and may not be representative of native North American amphibians. |
| Nutritional selenium should not be confused with selenium associated with heavy metals. | In the health assessment, exposure was assessed based on the whole blood selenium concentrations obtained from population level biomonitoring data. The assessment notes that all forms of selenium exposure contribute to the same pool of available selenium within the body. |
| Drinking water is an important source of selenium exposure for humans and should be highlighted in the RIAS. | Human exposure was assessed based on the whole blood selenium levels measured in population biomonitoring studies. Total selenium in whole blood provides a measure of exposure from all routes including oral, dermal, and inhalation and sources such as environmental media, diet, drinking water, and products. Although selenium exposure through drinking water was considered in the risk assessment, it was determined to be a minor source of selenium exposure. |
| Clarify whether elevated concentrations of selenium are from natural sources or a result of human activities. | The assessment considers the combined exposure to selenium and its compounds from natural and anthropogenic sources. The screening assessment and supporting documents compare concentrations from minimally impacted areas with those from areas impacted by human activities. |
| Is the selenium in some traditional foods eaten by Inuit (e.g. marine mammals) due to anthropogenic (human-made) sources? The mitigating effect of selenium on mercury was not taken into consideration in the assessment. The studies, such as Berry and Ralston 2008, should be included to address this point. | Although there are anthropogenic contributions that require further investigation, it is likely that selenium found in marine mammals is primarily from naturally occurring sources. The effects of selenium on heavy metal toxicity, including mercury toxicity, are considered in the RMA. |
2. Methodology
| Summarized Comment | Summarized Response |
|---|---|
| Include more analysis of the benefits of appropriate levels of selenium and not just the risks of excess selenium. | A full risk-benefit analysis is outside the scope of the RMA. However, the benefits of selenium are presented qualitatively in the RMA, the risk management documents, and all public communications. Additionally, Health Canada participated in the Institute of Medicine (IOM) evaluation of dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids (IOM 2000). These values are relevant for North American populations. |
| The human health objective should include the possibility that high selenium intake might protect against the adverse health effects of other substances, like mercury and arsenic. | Human health objectives are generally set to reduce the risks identified for a substance. For selenium and its compounds, the objective was to have the Canadian population below the upper tolerable intake levels for selenium. In its conclusion and proposed next steps, the RMA considers the benefits of the substance and jurisdictional considerations. For those consuming country foods that may be high in mercury and selenium, the RMA proposes continued research, communication, and sharing of expertise with local health authorities and other groups such as the Inuit Tapiriit Kanatami. |
| The Government of Canada should evaluate alternatives to selenium, if necessary. | There are no indications that selenium could be replaced with another substance because the areas identified for management either use selenium for a specific reason (e.g. vitamins) or note that selenium is present incidentally (e.g. elevated levels in fish due to mining releases) or naturally (e.g. selenium in certain food commodities). |
| The RMA should include the use of site-specific predicted no-effect concentrations (PNECs). Additionally, since some sensitive species only occur in select Canadian receiving waters, site-specific factors derived without the related endpoints should be reflected in the environmental and risk management objective. These objectives should also include economic factors. | The RMA is an informative document that outlines the actions planned by the Government of Canada to control selenium releases. The development of site-specific PNECs or factors is outside the scope of the RMA. The Risk Management Objective (RMO) does consider socio-economic factors. |
| The Government of Canada should have more oversight over monitoring pollutants in the environment. | Selenium and other toxic substances are monitored under the Chemicals Management Plan (CMP) Monitoring and Surveillance program. For metal mines and base metal smelters and refineries that share effluents with metal mines, monitoring of selenium and other substances is regulated by the MDMER under the Fisheries Act. |
| Highlight the criteria that were used to prioritize selenium under the CMP. | Substances in this grouping were prioritized for assessment as they met categorization criteria under Section 73(1) of CEPA or were included as a moiety-based assessment approach was taken. |
| Commercial and technological realities associated with selenium treatment and management have not been considered as they relate to the setting of effluent limits. | The RMA does not set effluent limits. The RMO considers socio-economic factors and Best Available Technology Economically Achievable. |
| Ecological risk assessment should prioritize field studies in Canada (or the lack thereof) confirming population effects over laboratory-based toxicity tests. | The ecological screening assessment considered Canadian field studies as a line of evidence when assessing the potential for selenium to cause ecological harm. Population-level effects observed in other jurisdictions and the results from reliable laboratory-based toxicity studies are also valid lines of evidence. |
| Subsistence fishers consuming fish from lakes downstream of mining operations should be compared to those consuming fish from lakes which are not downstream of mining operations. The analysis should be supported by robust statistical analysis. | Biomonitoring data for subsistence fishers were not available, therefore the risks of consuming fish caught downstream from mines were based on the comparison of measured concentrations of selenium in fish around mines and the health-based screening value for high fish consumption established by the British Columbia Ministry of Environment. |
| Reduce the frequency of the fish tissue selenium assessment in the Risk Management Approach for the coal and metal mining sectors and related regulations to six or more years between studies. | The MDMER was amended on May 30, 2018, to include the addition of a fish tissue study for selenium, as well as new substances to be monitored. Feedback from consultations will be considered as ECCC moves forward with the development of the proposed Coal Mining Effluent Regulations. |
| Align water quality guidelines for selenium with those of the U.S. EPA. | Environmental quality guidelines are based on protocols that are specifically developed and/or adopted by their jurisdiction. However, the toxicological data used in Canadian guidelines are often collected from the same studies that support thresholds and standards in guidelines for other jurisdictions. |
3. Exposure risks
| Summarized Comment | Summarized Response |
|---|---|
| Conduct research to determine whether the use of rubber containing selenium used in play areas is likely to result in excessive selenium intake by children, due to ingestion of dirt or dust. | Exposure was estimated based on biomonitoring data of whole blood concentrations measured in the Canadian population, including children. This includes data for selenium exposures from all sources, including selenium present in rubber materials and soil in playgrounds. There was no evidence of excessive selenium intake for children in Canada. |
| Concerns were raised related to the levels allowed in vitamins and mineral supplements. | These comments were considered while finalizing the RMA. |
4. Risk characterization
| Summarized Comment | Summarized Response |
|---|---|
| Selenium would not have an “immediate” effect on the environment or its biological diversity, as selenium has not been demonstrated to be acutely toxic. | Both acute and chronic impacts are considered in the assessment against the criteria for a toxic substance including “immediate or long-term harmful effect”. |
| The exceedance of blood selenium levels above the levels where selenosis has been reported does not indicate that there is a risk. | The health risk assessment has identified whole blood selenium levels in some Inuit populations that exceeds the levels where cases of selenosis have been reported. However, none of the available studies that monitored such levels in Inuit populations investigated the symptoms of selenosis. It is reasonable to assume that such highly exposed subpopulations may experience health risks. |
5. Conclusions
| Summarized Comment | Summarized Response |
|---|---|
| Statements used to describe the outcome of the assessment and the data used to reach conclusions need to be justified. | The statements form part of standard conclusion wording based on results of the screening assessment and language taken directly from CEPA. While the proposed order summarizes the outcome, it is the final screening assessment that presented specific scientific approaches, data used, and the lines of evidence that support the conclusion. |
| Provide proper justification for the statement that the Wastewater Systems Effluent Regulations will result in the removal of selenium to varying degrees. | While selenium is not directly targeted by the Wastewater Systems Effluent Regulations (WSER), additional treatment requirements at some wastewater treatment systems (WWTS) are expected to generate co-benefits for industrial sectors that send their effluent to a publicly-owned WWTS. This assumption is supported by concentrations of selenium measured in biological sludge and treated biosolids sampled at various WWTS through the CMP Monitoring and Surveillance Program. |
6. Risk management
| Summarized Comment | Summarized Response |
|---|---|
| The summary of international risk management activities needs to be clarified. | Additional information on Canadian and international risk management objectives for selenium and its compounds are available in the RMA and the summary of additional publications. |
| The Government of Canada should require industry to do testing and limit emissions, rather than rely on voluntary compliance. | Proposed risk management measures for selenium are on a regulatory basis and do not rely on voluntary compliance. |
| Blood tests may be appropriate for subsistence fishers who consume fish caught near or downstream from mines and other sites from which selenium is released to determine whether their selenium concentrations are at levels associated with toxicity. | Agreed. It would be advisable for those who consume fish caught in the vicinity of sites associated with the release of selenium, to consult a medical practitioner to confirm that levels of selenium in their serum and plasma are within a normal range. |
| Health Canada should ensure that at least three physicians or other health care practitioners in Canada are experts in recognizing signs of selenosis. | The signs of selenosis are well known and noted in the risk assessment and related documents. Although occurrences of selenosis in Canada are expected to be rare, several sub-populations were assessed as having higher exposures including Inuit in northern communities (high levels of selenium in blood); subsistence fishers near certain mines, and those consuming vitamin/mineral supplements that contain high levels of selenium. For those consuming country foods, the RMA proposes continued research, communication, and sharing of expertise with local health authorities and other organizations such as the Inuit Tapiriit Kanatami. |
| Putting up signs warning that fish from a particular lake should not be eaten does not work well enough. Public health authorities should work with communities located near waters containing contaminated fish to find ways to reduce consumption of contaminated fish. | The Government of Canada does not put up signs to warn about contaminated fish or foods hunted or gathered for consumption in a particular body of water or area. This type of risk management measure is done by local public health authorities, who may be informed by opinions on the potential risks posed by chemical substances in specific country foods or in the interpretation of biomonitoring results. For example, risk management measures such as issuing a consumption advisory order may be informed by CMP assessment results. |
| The substance should be added to the Priority Substances List instead of Schedule 1 to CEPA. Adding the substance to Schedule 1 to CEPA is costly for stakeholders and industry. | Schedule 1 to CEPA does not impose any regulatory or administrative burdens. The Government of Canada has the authority to introduce risk management or regulatory initiatives for substances listed on Schedule 1. Any such initiatives are subject to separate stakeholder consultation processes. |
| The Canadian Council of Ministers of the Environment (CCME) water quality guidelines regarding selenium are outdated. | Noted. CCME guidelines are not developed under the same authority as Canadian Federal Environmental Quality Guidelines. Rather, CCME guidelines are developed by collaborating environment ministers from the federal, provincial and territorial governments. |
References
Berry MJ, Ralston NVC. 2008. Mercury toxicity and the mitigating role of selenium. EcoHealth. 5:456-459.
[IOM] Institute of Medicine. 2000. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids: a report of the Panel on Dietary Antioxidants and Related Compounds, Subcommittees on Upper Reference Levels of Nutrients and of Interpretation and Use of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, Institute of Medicine. Washington (DC): National Academy Press.
Janz DM, Liber K, Pickering IJ, Wiramanaden CIE, Weech SA, Gallego-Gallegos M, Driessnack MK, Franz ED, Goertzen MM, Phibbs J, et al. 2014. Integrative assessment of selenium speciation, biogeochemistry, and distribution in a Northern coldwater ecosystem. Integ Environ Assess Manag. 10(4):543-554.
Lockard L, Rowe CL, Heyes A. 2013. Dietary selenomethionine exposure induces physical malformations and decreases growth and survival to metamorphosis in an amphibian (Hyla chrysoscelis). Arch Environ Contam Toxicol. 64:504-513.
Metts BS, Buhlmann KA, Scott DE, Tuberville TD, Hopkins WA. 2012. Interactive effects of maternal and environmental exposure to coal combustion wastes decrease survival of larval southern toads (Bufo terrestris). Environ Pollut. 164:211-218.
Massé AJ, Muscatello JR, Janz DM. 2015. Dose-dependent early life stage toxicities in Xenopus laevis exposed in ovo to selenium. Environ Sci Technol. 49:13658-13666.
Massé AJ, Muscatello JR, Janz DM. 2016. Effects of elevated in ovo selenium exposure on late stage development of Xenopus laevis tadpoles. Bull Environ Contam Toxicol. 97:463-468.
Massé AJ, Muscatello JR, Hogan NS, Janz DM. 2017. Tissue-specific selenium accumulation and toxicity in adule female Xenopus laevis chronically exposed to elevated dietary selenomethionine. Environ Toxicol Chem. 36(4): 1047-1055.
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