The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from zinc and its compounds.
Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
Zinc occurs naturally in zinc-enriched rocks and from human activities such as zinc metal production.
According to information gathered by the Government, zinc is primarily used for galvanizing iron and steel products to prevent corrosion and rust. Other activities and uses of zinc and its compounds in Canada include metal mining, as a component in metallic element and alloy processes, non-ferrous metal smelting and refining processes, fertilizers, hard material tools, paints and coatings, plastic, and rubber.
Zinc may be used in certain foods as a food additive or mineral nutrient.
Zinc may also be present in certain food packaging materials, as well as products available to consumers including drugs, cosmetics, natural health products (for example, multi-vitamin/mineral supplements), pesticides, sealants, cleaning products, automotive products, and plant fertilizers.
Human and ecological exposures
Food is the primary source of exposure of Canadians to zinc and its compounds. People may also be exposed to zinc and its compounds from environmental sources (for example, drinking water, soil, air, and house dust), and products available to consumers.
The assessment took into consideration the results of human biomonitoring studies. Measuring substances in blood, urine or breast milk is called biomonitoring and is done on an ongoing basis through health studies or surveys, such as the Canadian Health Measures Survey. Finding the substance in the body does not necessarily mean that it is causing harm. Harmful effects will depend on the levels and the properties of the substances. The information on measured levels in humans is important to estimating exposure to Canadians.
Zinc and its compounds have the potential to be released to the environment during industrial activities such as metal mining, base metals smelting (BMS) and refining, iron and steel manufacturing, and wastewater treatment systems.
Key health and ecological effects (hazard)
Although zinc is an essential element for human health, elevated intake may result in adverse health effects such as headaches, nausea, vomiting, loss of appetite, and abdominal cramps.
Zinc is also an essential element in plants and animals for a variety of biological functions but may be harmful at elevated concentrations. In excess, it may produce adverse effects on behavior, reproduction, and biochemical and physiochemical reactions.
The ecological hazard characterization for zinc took into account factors that affect toxicity such as hardness, pH and dissolved organic carbon.
Risk assessment outcomes
Based upon a comparison of levels of total zinc in urine of Canadians and levels associated with adverse health effects, it was determined that the risk to human health from zinc and its compounds is low.
Based upon the information presented in the screening assessment, it was determined that there is risk of harm to the environment from zinc and soluble zinc compounds. These substances may pose a risk to aquatic organisms through releases of zinc to water from metal mining effluent.
As a result of the assessment, the Government is proposing that zinc and its compounds are not harmful to human health at current levels of exposure.
However, the Government is proposing that zinc and soluble zinc compounds are entering the environment at levels that are harmful to the environment.
Preventive actions and reducing risk
The Government intends to add zinc and soluble zinc compounds to Schedule 1 of CEPA, 1999, also called the List of Toxic Substances.
The Government of Canada published the Risk Management Scope for Zinc and Soluble Zinc Compounds under the Zinc and its compounds grouping on June 29, 2019. The public are invited to comment on the scope during the 60-day public comment period ending on August 28, 2019. If the proposed conclusion is confirmed in the final screening assessment, the Government is considering the following actions to address ecological concerns:
Reducing release of zinc to water from metal mining activities by applying the updated zinc effluent limits in the Metal and Diamond Mining Effluent Regulations (MDMER).Information received from regulated mines in response to environmental effects monitoring requirements under these regulations will be reviewed to determine if additional regulatory or non-regulatory risk management is appropriate.
Reducing release of zinc to water from base metals smelting and refining by addressing facilities that are subject to the MDMER through the action proposed above for metal mining. Base metals smelting and refining facilities that are not subject to the MDMER are not proposed for risk management action.
Interested stakeholders are invited to provide information regarding dissolved concentrations of zinc in effluents, receiving environments, and reference areas for surface waters. Information on dissolved organic carbon, pH, and hardness related to these dissolved concentration of zinc in surface waters would be also be helpful.
Canadians are reminded to only take multi-vitamin/mineral supplements that have a Natural Product Number (NPN) on the label. Ingredient information can be found on the product label.
Zinc and its compounds may be found in products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
Canadians who may be exposed to zinc and its compounds in the workplace should consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
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