Canada Gazette, Part I, Volume 157, Number 39: GOVERNMENT NOTICES

September 30, 2023



Guidelines for Canadian Drinking Water Quality – Iron

Pursuant to subsection 55(3) of the Canadian Environmental Protection Act, 1999, the Minister of Health hereby gives notice of the Guidelines for Canadian Drinking Water Quality – Iron. The proposed technical document for these guidelines is available from September 29, 2023, to November 28, 2023, on the Health Canada consultation web page. Any person may file written comments on the proposed document with the Minister of Health within 60 days after its publication.

September 21, 2023

Greg Carreau
Director General
Safe Environments Directorate
On behalf of the Minister of Health


Proposed guideline

An aesthetic objective (AO) of ≤ 0.1 mg/L (100 µg/L) is proposed for total iron in drinking water.

Executive summary

This guideline technical document was prepared in collaboration with the Federal-Provincial-Territorial Committee on Drinking Water and assesses all available information on iron.


Iron is a ubiquitous metal that enters the environment from both natural sources and human activities. It occurs mostly in the form of organic and inorganic compounds and, to a lesser extent, in its metallic form. Iron is used mainly for steel production and industrial, commercial and consumer product applications, such as water mains, batteries, pesticides, fertilizers, cosmetics, food additives and multivitamin supplements.

People living in Canada are exposed to iron mainly through food and, to a lesser extent, through drinking water, principally because of corrosion in the distribution system. Exposure through drinking water contributes less than 10% of the total daily iron intake. In most Canadian sources of water, the median iron concentration is below 1 mg/L. Higher concentrations are typically found in groundwater. The iron content in treated water entering the distribution system is generally very low. Elevated iron concentrations are likely to result in an off-flavour (bitter or metallic taste), and discoloured water.

Health effects

Iron is an essential element for humans. However, oral exposure to very high levels may cause adverse health effects, with gastrointestinal distress being the most sensitive endpoint. The overall weight of scientific evidence indicates that iron is neither a reproductive toxicant nor a developmental toxicant nor a carcinogen.

Aesthetic considerations

Concerns about iron in drinking water are often related to consumer complaints regarding discoloured water. The proposed AO of  0.1 mg/L (100 µg/L) is intended to minimize the occurrence of discoloured water due to the presence of iron oxides and to improve consumer confidence in drinking water quality. It is important to note that when both iron and manganese (Mn) are present, the removal of iron generally improves the removal of Mn, thus reducing the health risk associated with this metal.

Analytical and treatment considerations

The development of a drinking water guideline takes into consideration the ability to measure the contaminant and to remove it from drinking water supplies. Several analytical methods are available for measuring iron in water at concentrations well below the proposed AO. Total iron, which includes both the dissolved and particulate forms of iron in a water sample, should be measured.

At the municipal level, treatment technologies that are available to effectively decrease iron concentrations in drinking water include aeration, chemical oxidation followed by filtration, coagulation, adsorption, membrane filtration, and coagulation followed by ultrafiltration. The performance of these technologies depends on factors such as iron species, pH, coagulant type, coagulant dose and type of adsorbent. Using appropriate process controls, these technologies can achieve treated water concentrations well below the proposed AO. Most well-operated and optimized treatment plants can achieve iron concentrations of 0.1 mg/L or less in the treated water. The proposed AO of  0.1 mg/L would minimize the occurrence of discoloured water and taste complaints, aid in the removal of co-occurring Mn, ensure that a disinfectant residual is maintained and improve consumer confidence in drinking water quality. Prior to full-scale implementation, bench- and/or pilot-scale studies should be conducted using source water to ensure sufficient iron removal and to optimize performance.

In cases where iron removal is desired at a small-system or household level, for example a private well, a residential drinking water treatment unit may be an option. Although there are no treatment units currently certified for the removal of iron from drinking water, technologies that are expected to be effective include ion exchange, oxidizing filters and reverse osmosis. When using a residential drinking water treatment unit, it is important to take samples of water entering and leaving the treatment unit and send them to an accredited laboratory for analysis, to ensure that adequate iron removal is achieved. Routine operation and maintenance of treatment units, including replacement of filter components, should be conducted according to manufacturer specifications.

Distribution system

It is recommended that water utilities develop a distribution system management plan to minimize the release of iron and the potential for co-occurring contaminants in the system. This includes minimizing the iron concentration entering the distribution system and distribution system maintenance (main cleaning). It is particularly important to maintain stable chemical and biological water quality conditions throughout the system and minimize physical and hydraulic disturbances that can release iron corrosion by-products.

Application of the guidelines

Note that specific guidance on implementing drinking water guidelines should be obtained from the appropriate drinking water authority.

All water utilities should implement a risk management approach, such as the source-to-tap or water safety plan approach, to ensure water safety. These approaches require a system assessment to characterize the source water, describe the treatment barriers that prevent or reduce contamination, identify the conditions that can result in contamination, and implement control measures. Operational monitoring is then established and operational and management protocols, such as standard operating procedures, corrective actions and incident responses, are instituted. Other protocols to validate the water safety plan, such as record keeping and consumer satisfaction, are also implemented. Operator training is also required to always ensure the effectiveness of the water safety plan.

Considering that iron levels can vary significantly in source water, within treatment plants, and especially in distribution systems, monitoring programs should be system specific to enable utilities to have a good understanding of iron levels from source to tap. Monitoring programs should be designed based on risk factors that contribute to the likelihood of finding elevated iron levels in the drinking water system. These factors may include historical infrastructure (for example presence of unlined cast-iron mains), lack of treatment, limited distribution system maintenance and variable source and distribution system water chemistry. The sampling locations, frequency and type of samples that should be collected will differ depending on the desired goal (such as identifying sources of iron, minimizing accumulation and removal of co-occurring Mn) and site-specific considerations. Suggested monitoring details for different points in a drinking water system are provided in section 5.2 of the technical document.

Total iron in drinking water should be monitored at the tap when discolouration (coloured water) events occur. Discolouration events may be accompanied by the release of accumulated contaminants, including arsenic (As), lead (Pb), Mn and radiological contaminants. Iron oxides can adsorb and accumulate these contaminants and release them into the bulk water and plumbing systems. Therefore, discoloured water events should not be considered only an aesthetic issue; they should trigger sampling for iron and other metals and possibly distribution system maintenance.



Proposed Residential Indoor Air Quality Guidelines for Benzene

Pursuant to subsection 55(3) of the Canadian Environmental Protection Act, 1999, the Minister of Health hereby gives notice of the proposed Residential Indoor Air Quality Guidelines for Benzene. The proposed Residential Indoor Air Quality Guidelines (RIAQG) are available from September 30, 2023, to November 29, 2023, on the Health Canada consultation web page. Any person may, within 60 days after publication of this notice, file with the Minister of Health written comments on the proposed RIAQG. Comments must be sent by email to

September 30, 2023

Greg Carreau
Director General
Safe Environments Directorate
On behalf of the Minister of Health


Benzene is a volatile organic compound with a high vapour pressure that quickly evaporates into the air when released into the environment. Indoor concentrations of benzene are generally higher than outdoor concentrations. Key sources of ambient (outdoor) benzene concentrations are vehicular emissions and industrial emissions. Additional important sources of benzene outdoors include releases from gasoline stations, wildfires, and residential wood burning.

In homes in Canada, indoor benzene concentrations are 1.3 to 7.9 times higher than outdoor concentrations, with the highest ratios of indoor-to-outdoor concentration observed in homes with people who smoke. The presence of an attached garage, people smoking indoors, the storage of gasoline, paints, and solvents in the garage and home, and the infiltration from outdoor air have all been associated with higher levels of benzene in the home. Increased ventilation is associated with lower indoor benzene.

The proposed long-term guideline value for benzene is 0.6 μg/m3.

Median residential indoor benzene levels measured from 2005 to 2019 by Health Canada ranged from 0.4 to 2.2 μg/m3 in multiple cities and two First Nations communities, and the 95th percentiles ranged from 2.4 to 18.6 μg/m3. The national average concentration of outdoor benzene in 2019 was 0.5 μg/m3. Levels of benzene in many homes in Canada may exceed the guideline value and may pose a health risk. It is therefore recommended to reduce exposure to benzene by ensuring adequate ventilation and controlling or eliminating indoor sources.

Health effects

Benzene is genotoxic and is classified as a human carcinogen by Health Canada, the International Agency for Research on Cancer, and the United States Environmental Protection Agency. Benzene causes acute myeloid leukemia and acute non-lymphocytic leukemia in adults. There is also growing evidence supporting a positive association between benzene exposure and leukemia in children.

Hematotoxicity, including decreased blood cell counts and effects on precursor cell populations in bone marrow, is a well-established non-cancer effect of benzene exposure that occurs in occupational settings and potentially at environmental concentrations. In addition, results from recently published studies indicate that benzene exposure at environmentally relevant concentrations may also be associated with respiratory, reproductive and developmental toxicity.

Several populations may be vulnerable to benzene exposure. In studies in Canada, higher levels of blood benzene or urinary metabolites were found in people who smoke, South Asian Canadians, and Indigenous women. Women are expected to be more susceptible to health effects related to benzene exposure than men in the same setting due to metabolic differences. However, men may have a higher exposure to benzene due to behavioural factors. Children are also expected to be more susceptible due to physiological and metabolic differences compared to adults. Genetic polymorphisms that affect benzene metabolism and increase susceptibility to adverse effects may be present in a significant proportion of the population.

Risk management recommendations

Strategies to reduce indoor exposure to benzene include improving ventilation and controlling indoor sources. This may be done by increasing natural ventilation by opening windows (taking into consideration ambient air quality) or by employing mechanical ventilation strategies (heating, ventilation, and air conditioning system). To prevent emissions of benzene within the home, it is best to avoid storing gasoline and other chemicals in the home or attached garage, and to seal containers well, if stored. The interface between an attached garage and the home should be properly sealed, and cars, snowblowers, lawn mowers, or any gas-powered equipment should not be left idling in the attached garage. Consider installing an exhaust fan in an attached garage. Do not smoke indoors. In addition, ensure that fireplaces and wood stoves are properly installed and maintained, and vent pollutants to the outdoors. When outdoor levels of benzene are high, occupants should take measures to protect their indoor air quality, such as limiting the infiltration of outdoor air.

About the guidelines

The RIAQG summarize the known health effects, pollutant sources, and exposure levels in homes in Canada and characterize the risks to health, based on the best scientific data available. Proposed exposure limits (also referred to as guideline values) for short- and/or long-term exposure to the pollutant are developed, representing indoor air concentrations below which health effects are unlikely to occur. The proposed exposure limits take into account the risk-specific concentration (RSC) for the pollutant and the feasibility of achieving such levels through control of indoor sources. The RIAQG also include evidence-based recommendations for controlling sources or other actions to reduce exposure to the pollutant.



Notice No. DGSO-007-23 — Decision on Conditions of Licence relating to the Provision of Service within the Toronto Transit Commission (TTC) Subway System

The intent of this notice is to announce the release of the document entitled DGSO-007-23, Decision on Conditions of Licence relating to the Provision of Service within the Toronto Transit Commission (TTC) Subway System, which sets out Innovation, Science and Economic Development Canada’s (ISED) conditions of licence with respect to providing commercial mobile services in the TTC subway system.

Obtaining copies

Copies of this notice and of documents referred to herein are available electronically on the ISED Spectrum Management and Telecommunications website.

Official versions of notices can be viewed on the Canada Gazette website.

September 26, 2023

Marc-André Rochon
Senior Director
Spectrum Management Operations Branch


Appointment opportunities

We know that our country is stronger — and our government more effective — when decision-makers reflect Canada’s diversity. The Government of Canada has implemented an appointment process that is transparent and merit-based, strives for gender parity, and ensures that Indigenous peoples and minority groups are properly represented in positions of leadership. We continue to search for Canadians who reflect the values that we all embrace: inclusion, honesty, fiscal prudence, and generosity of spirit. Together, we will build a government as diverse as Canada.

We are equally committed to providing a healthy workplace that supports one’s dignity, self-esteem and the ability to work to one’s full potential. With this in mind, all appointees will be expected to take steps to promote and maintain a healthy, respectful and harassment-free work environment.

The Government of Canada is currently seeking applications from diverse and talented Canadians from across the country who are interested in the following positions.

Current opportunities

The following opportunities for appointments to Governor in Council positions are currently open for applications. Every opportunity is open for a minimum of two weeks from the date of posting on the Governor in Council appointments website.

Governor in Council appointment opportunities
Position Organization Closing date
Director Asia-Pacific Foundation of Canada  
Director Bank of Canada  
Chairperson Business Development Bank of Canada  
Director Business Development Bank of Canada  
Director Canada Foundation for Innovation  
Director Canada Foundation for Sustainable Development Technology  
Chairperson Canada Mortgage and Housing Corporation  
Director Canada Mortgage and Housing Corporation  
Director Canada Revenue Agency  
Chairperson Canadian Accessibility Standards Development Organization  
Director Canadian Accessibility Standards Development Organization  
Director Canadian Centre on Substance Abuse  
Director Canadian Commercial Corporation  
Chief Executive Officer Canadian Energy Regulator  
Commissioner Canadian Energy Regulator  
Chief Commissioner Canadian Grain Commission  
Chief Commissioner Canadian Human Rights Commission  
Member Canadian Human Rights Tribunal  
Member Canadian Institutes of Health Research  
President Canadian Institutes of Health Research  
Member Canadian International Trade Tribunal  
Member Canadian Nuclear Safety Commission  
President Canadian Nuclear Safety Commission  
Member Canadian Radio-television and Telecommunications Commission  
Member Canadian Statistics Advisory Council  
Director Canadian Tourism Commission  
Chairperson Canadian Transportation Accident Investigation and Safety Board  
Member Canadian Transportation Accident Investigation and Safety Board  
Member Canadian Transportation Agency  
Member Copyright Board  
Director Export Development Canada  
Director First Nations Financial Management Board  
Commissioner First Nations Tax Commission  
Director (Federal) Halifax Port Authority  
Member Historic Sites and Monuments Board of Canada  
Clerk of the House of Commons House of Commons  
Law Clerk and Parliamentary Counsel House of Commons  
Dispute/Appellate Panellist Internal Trade Secretariat – Canadian Free Trade Agreement  
Commissioner International Commission on the Conservation of Atlantic Tunas  
Commissioner International Joint Commission  
Chairperson Military Grievances External Review Committee  
Vice-Chairperson Military Grievances External Review Committee  
Chairperson National Advisory Council on Poverty  
Member National Advisory Council on Poverty  
Member (Children’s Issues) National Advisory Council on Poverty  
Commissioner National Battlefields Commission  
Chairperson National Seniors Council  
Member National Seniors Council  
Canadian Representative North Atlantic Salmon Conservation Organization  
Canadian Representative North Pacific Anadromous Fish Commission  
Conflict of Interest and Ethics Commissioner Office of the Conflict of Interest and Ethics Commissioner  
Director of Public Prosecutions Office of the Director of Public Prosecutions  
Member Patented Medicine Prices Review Board  
Director Public Sector Pension Investment Board  
President Public Service Commission  
Principal Royal Military College of Canada  
Member Social Sciences and Humanity Research Council  
Member Standards Council of Canada  
Chairperson Telefilm Canada  
Member Telefilm Canada  
Director VIA Rail Canada Inc.