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Drinking Water Safety

Is there arsenic in my drinking water?

​​​​​​​​​​​​​​​​​​​​​​​​​​​​What is arsenic?

Arsenic is an element found in nature. 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, rocks, and minerals. It is also found in some pesticides, fertilizers, and treated wood products.

How does arsenic get into my drinking water?

Arsenic gets into water directly through rocks, minerals, ores, industrial waste, and deposits from the air.

Arsenic can also get into water from run-off (water flowing across the surface of land) and leaching (water flowing through soil). Arsenic can leach into water from:

  • ​​compost and animal waste
  • soil that's been used to dispose of sewage sludge
  • pesticides with arsenic
  • industrial by-products like coal fly ash
  • ​soil that's been used to dispose of 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
  • recycled mulch from CCA-treated wood
  • CCA-treated wood dump sites

How does arsenic affect my health?

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

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

Arsenic might also cause respiratory disease, heart disease, nervous system problems, GI problems, and blood diseases.

​The risk to your health depends on:

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

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

You may also have some exposure to arsenic when you take a bath or shower using water with arsenic as it gets on your skin. You might also breathe in water droplets while bathing or showering.

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. Learn more about testing your drinking water in Alberta.

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

If you have a private water source, do a chemical and trace metals test to make sure it’s safe to drink. Make sure to have your water sample tested by an accredited lab.

What is the standard for levels of arsenic in drinking water?

Treatment processes for removing arsenic are limited, so Health Canada’s Guidelines for Canadian Drinking Water Quality have set the maximum acceptable concentration (MAC) of arsenic in drinking water at 0.01 mg/L (milligrams per litre) even though health risks are possible below this level.

Try to keep arsenic levels in drinking water as low as possible.

What should I do if I find arsenic in my drinking water?

If you are concerned about arsenic in your drinking water:

  • Use water from another safe source to drink, cook, and brush your teeth. Safe water sources include municipal water systems or bottled water.
  • Talk to a professional water specialist about how to treat your water to remove arsenic.

You can remove arsenic from drinking water with:

  • reverse osmosis (forcing water through a membrane that filters out elements including arsenic)
  • distillation (a system that boils water, catches the steam, and condenses it to liquid while leaving the arsenic out)
  • granules that absorb arsenic (activated alumina)
  • 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 your 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 the manufacturer’s instructions.

Where can I learn more?

If you have any questions about arsenic in drinking water, contact Alberta Health Services Environmental Public Health.

Current as of: April 26, 2022

Author: Environmental Public Health, Alberta Health Services