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July 23, 2015

Environment Canada Completes Risk Assessment for Selenium

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Health Canada and Environment Canada conducted a joint scientific assessment of Selenium and its compounds in Canada under section 68 or 74 of CEPA 1999, and under the Selenium-containing Substance Grouping of the CMP Substance Grouping Initiative. A notice summarizing the scientific considerations of the draft Screening Assessment (dSAR) for these substances was published in the Canada Gazette, Part I, on July 18, 2015.

The final recommendation of the screening was to add selenium and its compounds to the List of Toxic Substances.
The ecological risks of concern, identified in the dSAR, are primarily based on the release of selenium to water from metal and coal mining, base metals smelting and refining, power generation, agriculture, and publicly owned wastewater treatment. The potential human health risks of concern, identified in the dSAR, are based on the identification of subpopulations who have or potentially have elevated selenium exposure levels. A small percentage of Inuit who eat country foods have been identified as a subpopulation with elevated exposures. Subsistence fishers consuming fish with elevated selenium concentrations (e.g. fish caught around some mining operations) and individuals consuming multi-vitamin/mineral supplements providing high levels of selenium are two additional subpopulations in Canada with the potential for elevated selenium exposure. 

 The Proposed Risk Management document is available from the Environment Canada website. Several sectors will be required to reduce selenium emissions.
Of wastewater treatment facilities specifically the document proposes no further action, anticipating that the implementation of the Wastewater System Effluent Regulations and a national standard of secondary treatment along with reductions in selenium discharges from industry within the collection system will adequately reduce selenium discharges from the sector. The document says specifically:
The risk for the wastewater sector is low and limited to potentially very few facilities. In 2012, Environment Canada published the Wastewater Systems Effluent Regulations (WSER), which set standards for the quality of effluent discharged from wastewater treatment facilities that are achievable through secondary wastewater treatment. As these regulations come into effect, a reduction in selenium releases is anticipated over time. It is expected that the regulations may simultaneously address selenium released from various industries that send their effluent to a publicly owned wastewater treatment plant (WWTP) and from the consumer use of products containing selenium that are washed down the drain. Environment Canada will consider the effect of the regulations on selenium to determine if additional risk management is required. 


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