Arsenic is a naturally occurring chemical element in soil. It can dissolve in groundwater and contaminate it. Water is not the only source of exposure to arsenic. Some foods, such as rice, chicken, seafood and mushrooms, also contain low concentrations of arsenic.
By Québec standards, the concentration of arsenic in drinking water should not exceed 0.010 mg/L. Considering that arsenic can have serious effects on health, its concentration in drinking water should always be as low as possible.
People exposed to arsenic over many years are at higher risk of suffering from:
- Blood circulation problems
- Skin cancer
- Lung cancer
- Bladder cancer
Persons most susceptible to the effects of arsenic include:
- Smokers; they are more susceptible to the carcinogenic effects of arsenic
- Pregnant women and bottle-fed babies are more susceptible given the possible effects on child development
Protection and prevention
Your water should be tested for arsenic at least once during the period of usage of the well, ideally in the spring or fall. If the concentration of arsenic in your well exceeds 0.010 mg/L, use another source, or bottled water, to:
- Prepare beverages
- Prepare feeding bottles and baby food
- Prepare food
- Cook food with water
You can use tap water to:
- Wash food
- Steam food
- Wash dishes and clothes
- Take a shower or bath
Boiling water is pointless because arsenic does not evaporate. In fact, doing so can increase the concentration of arsenic in the water.
You can install a residential water treatment system to reduce the concentration of arsenic in water to an acceptable level. Be sure to install a certified system that conforms to NSF/ANSI standards and follow the manufacturer’s maintenance recommendations. If you install a residential water treatment system to eliminate barium from your water, you must verify its effectiveness by testing your water every year.
Contaminants in Drinking Water
Fluoridation of Drinking Water
Information sheet - I’m getting my well water tested
Frequently asked questions about manganese in drinking water (in French only)
Institut national de santé publique du Québec