Canada Gazette, Part I, Volume 159, Number 2: GOVERNMENT NOTICES

January 11, 2025

DEPARTMENT OF HEALTH

CANADIAN ENVIRONMENTAL PROTECTION ACT, 1999

Guidelines for Canadian drinking water quality — Trihalomethanes

Pursuant to subsection 55(3) of the Canadian Environmental Protection Act, 1999, the Minister of Health hereby gives notice of the draft Guidelines for Canadian drinking water quality — Trihalomethanes. The proposed guideline document is available from January 10 to April 4, 2025, and can be found on Health Canada’s Environment and workplace health consultations web page. Any person may file written comments on the proposed document with the Minister of Health within 60 days after publication of this notice. Comments must be sent by email to water-consultations-eau@hc-sc.gc.ca.

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

ANNEX

Proposed guideline

The proposed maximum acceptable concentration (MAC) for trihalomethanes (THMs) in drinking water is 0.100 mg/L (100 µg/L) based on a locational running annual average of a minimum of quarterly samples taken at the points in the distribution system with the highest potential for THM levels. Total THMs is the sum of the four THM species: chloroform, BDCM, DBCM, and bromoform. Utilities should make every effort to maintain concentrations as low as reasonably achievable without compromising the effectiveness of disinfection.

Executive summary

This guideline technical document was prepared in collaboration with the Federal-Provincial-Territorial Committee on Drinking Water and assesses all relevant information on THMs. An assessment of the current information on iodinated THMs (I-THMs), which are contaminants of emerging concern, was also conducted. However, no guideline value was derived for these substances.

Exposure

THMs are a group of disinfection by-products that are formed primarily when the chlorine used to disinfect drinking water reacts with organic matter found naturally in raw water supplies. The main sources of Canadians’ exposure to THMs are the ingestion of THMs in drinking water and the inhalation and dermal absorption of THMs from water-related activities (for example bathing and showering).

Chloroform is the THM found most often and at the highest concentration in drinking water. BDCM, DBCM and bromoform may be present, typically at lower concentrations than chloroform. Total THMs is the sum of the four THM species: chloroform, BDCM, DBCM, and bromoform. Higher concentrations of THMs are typically found in drinking water in summer and fall and in distribution system locations with the highest water age. I-THMs, if present, are generally at low concentrations.

Health effects

Studies in humans have found associations between exposure to THMs in drinking water and bladder cancer; and a potential association between exposure to THMs in drinking water and reproductive/developmental effects (in particular, small for gestational age). Given the potentially hundreds of disinfection by-products in drinking water, it is a challenge to identify the chemicals responsible for health effects.

Studies in animals show that exposure to THMs primarily affects the liver and the kidney. Depending on the THM, effects are also observed in the colon, in the thyroid and in nasal tissues. A health-based value (HBV) of 1.4 mg/L was determined for chloroform based on effects observed in the kidney in rats. An HBV of 0.100 mg/L for BDCM was determined based on intestinal tumours in rats. The HBVs take into account all exposures from drinking water (whether by ingestion, inhalation or dermal absorption). Insufficient data were available to derive HBVs for DBCM and bromoform.

Toxicological data have consistently shown that brominated disinfection by-products such as BDCM, DBCM and bromoform are more potent than chlorinated disinfection by-products such as chloroform. For this reason, the proposed MAC of 0.100 mg/L for the total concentration of chloroform, BDCM, DBCM and bromoform is based on the lowest HBV calculated for BDCM and is considered to be protective of the health effects of all four THMs.

Very limited toxicity data exist for I-THMs, so it is not possible to derive an HBV for these substances.

Analytical and treatment considerations

The development of a drinking water guideline takes into consideration the ability to both measure the contaminant and reduce its concentration in drinking water. Several analytical methods are available for measuring THMs in water concentrations well below the proposed MAC. Measurements in a water sample should be for total THMs, including chloroform, BDCM, DBCM and bromoform.

The approach to reducing exposure to THMs is generally focused on reducing the formation of chlorinated disinfection by-products. Concentrations of THMs and other chlorinated disinfection by-products in drinking water can be reduced at the treatment plant by removing the natural organic matter from the water before chlorine is added, optimizing the disinfection process, using an alternative disinfection strategy or using a different water source. It is critical that any method used to control THM levels not compromise the effectiveness of disinfection. The consumption of untreated or inadequately treated water should be avoided.

Distribution system

THMs continue to form within the distribution system. For this reason, it is recommended that water utilities develop a distribution system management plan to minimize the formation of THMs. Strategies to reduce THM formation within the distribution system, which may include optimizing distribution system chlorination, switching to chloramines, system flushing, and decreasing water age, can be implemented. Well-developed, well-calibrated and well-maintained distribution system models may provide another option to assess water age and simulate chlorine decay and THM formation. Aeration may be able to reduce already formed THMs. As with control methods, it is critical that control strategies not compromise the effectiveness of disinfection.

DEPARTMENT OF INDUSTRY

OFFICE OF THE REGISTRAR GENERAL

Appointment

Instrument of Advice dated December 16, 2024

December 16, 2024

Rachida Lagmiri
Official Documents Registrar

DEPARTMENT OF INDUSTRY

OFFICE OF THE REGISTRAR GENERAL

Appointments

January 3, 2025

Rachida Lagmiri
Official Documents Registrar

DEPARTMENT OF INDUSTRY

OFFICE OF THE REGISTRAR GENERAL

Senators called

Her Excellency the Governor General has been pleased to summon to the Senate of Canada, by letters patent under the Great Seal of Canada bearing the date of December 19, 2024:

December 19, 2024

Rachida Lagmiri
Official Documents Registrar

DEPARTMENT OF INDUSTRY

INVESTMENT CANADA ACT

Amounts for the year 2025

Limits for trade agreement investors

Pursuant to subsections 14.11(1), (2) and (3) of the Investment Canada Act, I hereby determine that the amount for the year 2025, equal to or above which an investment is reviewable, is 2.079 billion dollars.

Limits for World Trade Organization investors

Pursuant to subsections 14.1(1) and (2) of the Investment Canada Act, I hereby determine that the amount for the year 2025, equal to or above which an investment is reviewable, is 1.386 billion dollars.

Limits for World Trade Organization investors that are state-owned enterprises

Pursuant to subsections 14.1(1.1) and (2) of the Investment Canada Act, I hereby determine that the amount for the year 2025, equal to or above which an investment is reviewable, is 551 million dollars.

François-Philippe Champagne
Minister of Industry

PRIVY COUNCIL OFFICE

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 Bank of Canada  
Chairperson Canada Deposit Insurance Corporation  
Chairperson Canada Industrial Relations Board  
Vice-Chairperson Canada Industrial Relations Board  
Chairperson Canada Infrastructure Bank  
Director Canada Lands Company Limited  
President Canada Water Agency  
Chief Executive Officer Canadian Accessibility Standards Development Organization  
Assistant Chief Commissioner Canadian Grain Commission  
President Canadian High Arctic Research Station  
Chief Commissioner Canadian Human Rights Commission  
Permanent Member Canadian Nuclear Safety Commission  
Director Canadian Tourism Commission  
President Canadian Tourism Commission  
Chairperson Civilian Review and Complaints Commission for the Royal Canadian Mounted Police  
Vice-Chairperson Civilian Review and Complaints Commission for the Royal Canadian Mounted Police  
Director Defence Construction (1951) Limited  
Reviewer Department of Citizenship and Immigration  
Member Employment Insurance Board of Appeal February 3, 2025
Vice-Chairperson Federal Public Sector Labour Relations and Employment Board  
Chairperson First Nations Infrastructure Institute  
Director First Nations Infrastructure Institute  
Director (Federal) Halifax Port Authority  
Member Historic Sites and Monuments Board of Canada  
Member National Seniors Council  
Member Natural Sciences and Engineering Research Council  
Commissioner of Official Languages Office of the Commissioner of Official Languages  
Deputy Director of Public Prosecutions Office of the Director of Public Prosecutions  
Ombudsperson for the Department of National Defence and the Canadian Forces Office of the Ombudsperson for the Department of National Defence and the Canadian Forces  
Member Payments in Lieu of Taxes Dispute Advisory Panel  
Chief Public Health Officer Public Health Agency of Canada  
Principal Royal Military College of Canada  
Director Sept-Îles Port Authority  
Administrator Ship-source Oil Pollution Fund and Fund for Railway Accidents Involving Designated Goods  
Co-chair Sustainable Jobs Partnership Council  
Member Sustainable Jobs Partnership Council  
Chairperson The Jacques-Cartier and Champlain Bridges Inc.  
Secretary The National Battlefields Commission
Member Transportation Appeal Tribunal of Canada  
Chairperson VIA Rail Canada Inc.  
Chairperson Windsor-Detroit Bridge Authority