Bowen Island Municipality has detected elevated levels of disinfection by-products (DBPs) in the Hood Point water supply that are higher than the recommended Health Canada guidelines.
Chlorinated DBPs are formed when the chlorine that is used to disinfect drinking water reacts with naturally occurring organic matter. Disinfection is an essential component of public drinking water treatment and the risks associated with DBPs are far fewer than consuming water that has not been disinfected.
The most common DBPs are trihalomethane (THMs) and haloacetic acids (HAAs) and their levels within a single water supply will vary depending on season, water temperature, levels of organic matter in the water, pH amount in chlorine added, time in the distribution system, and other factors.
Drinking, bathing, and showering can expose you to chlorinated DBPs. Health Canada has conducted studies into the long-term health effects of THM and HAA exposure and consumption. While no direct links have been identified, it has been suggested that they could have associated reproductive effects, slightly elevated levels of bladder and colon cancer, as well as concerns surrounding the liver and kidneys.
Bowen Island Municipality has taken or will be taking the following actions:
- Increase DBP monitoring frequency to monthly, with additional sampling sites added.
- Inspect and clean the water intake in Honeymoon Lake.
- Clean the Hood Point water storage tank.
- Closely monitor and optimize chlorine residuals in the system to ensure adequate chlorination in the distribution is always maintained.
- Ensure efficient filter operation.
- Open sample taps to increase flow in the distribution system and decrease time water spends in the distribution system.
- Conduct additional raw water sampling to determine byproduct precursors and their concentrations, including tannins and total organic carbon.
- Seek additional advice from private water treatment providers.
Find more detailed information on the Question and Answer sheet.
For further information regarding the operation of the Hood Point Water System, please contact the Bowen Island Municipality, Public Works Department at 604-947-4255 ext 4 or email publicworks@bimbc.ca
For further information regarding health implications, please contact Vancouver Coastal Health Authority, Environmental Health at 604-983-6793.