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Drinking Water Safety

Is there Arsenic in My Drinking Water?

​​​​​What is arsenic?

Arsenic is an element found in soil, rocks, and minerals. It is used to harden copper and make things like:
  • glass
  • electronic devices
  • wood preservatives
  • chemicals for farming

Where is arsenic found?

Arsenic is found naturally in soil and minerals.

How does arsenic get into my water?

Arsenic gets into water through rocks, minerals, ores, industrial waste, and deposits from the air. Arsenic can also get into water from run-off and leaching. Arsenic can leach into water from:

  • compost and animal waste
  • from soil that's been used to dispose sewage sludge
  • pesticides with arsenic
  • industrial by-products (e.g., coal fly ash)
  • from soil that's been used to dispose recycled dirt and sediments collected from street-sweeping
  • dredged sediments when soil is reclaimed and enhanced
  • fertilizer and soil amendments
  • chromated copper arsenate (CCA)-treated wood
    (90% of outdoor wooden structures in the USA)
  • recycled mulch from CCA-treated wood
  • CCA-treated wood dump sites

How can arsenic affect my health?

People are exposed to arsenic when they drink water which contains arsenic.

Arsenic is classified as a human carcinogen. Being exposed to arsenic for many years may increase the risk of these types of cancer:

  • skin
  • bladder
  • kidney
  • liver
  • gastrointestinal (GI)
  • bone

Studies show that arsenic might cause respiratory disease, heart disease, nervous system problems, GI problems, and blood diseases.

Children might be exposed to more arsenic because they drink more water per kilogram than adults do.

The risk to your health depends on how:

  • much arsenic is in your water
  • much water you drink every day
  • sensitive you are to arsenic
  • long you've been drinking the water

You may have limited exposure to arsenic when you bath or shower using water with arsenic as it gets on your skin and you might breathe in water droplets.

What is the standard for arsenic in drinking water?

Treatment processes for removing arsenic are limited, so Health Canada has set the maximum acceptable concentration (MAC) of arsenic in drinking water at 0.010 milligrams per litre (mg/L). Since this guideline is higher than the level that’s considered no risk, try to keep arsenic levels in drinking water as low as possible.

How do I know if there is arsenic in my drinking water?

You can't see, taste, or smell arsenic. Your water can be tested to see how much arsenic is in it.

All public water supplies are checked for total arsenic. You can find out results from the supplier.

If you have a private water source, make sure to have a chemical test done to make sure it is safe to drink. Make sure to have your water sample tested by an accredited lab.

What if I find arsenic in my drinking water?

If there is a concern with arsenic in any public water supply, contact your municipal supplier or Alberta Environment and Parks.

If a consumer/well owner is concerned about arsenic in drinking water:

  • use water from another source that's safe (e.g., municipal system, bottled water) to drink, cook, and brush teeth
  • talk to a professional water specialist about how to treat water to remove arsenic.
You can remove arsenic from drinking water:
  • with reverse osmosis
  • by distilling it
  • using granules that absorb arsenic (activated alumina)
  • with other certified filtration units
Any treatment device must be certified to meet these standards:
  • NSF/ANSI standard 62 on drinking water distillation systems
  • NSF/ANSI standard 58 on reverse osmosis drinking water systems
  • NSF/ANSI standard 53 on drinking water treatment units (approved for arsenic removal)

After you have installed your system, have the treated water tested for total arsenic at a private accredited lab to make sure your system is working properly. Monitor and maintain your water treatment equipment according to manufacturer instructions.

If you have any questions about arsenic in water, call Environmental Public Health.

Current as of: March 13, 2018

Author: Environmental Public Health, Alberta Health Services