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Chemicals and Minerals found in Drinking Water

What kind of chemicals can be found in drinking water?
Trihalomethanes (THM)
THM are chemical compounds that react to organic matter in surface water when chlorine is used for disinfecting the drinking water. Current evidence shows that THMs do not pose an immediate health risk. However, studies suggest that long term exposure (more than 35 years) may be linked to an increase in certain types of cancer. The potential risks associated with drinking water containing THMs are much lower than the risks of drinking water that has not been properly disinfected. The Ontario Drinking Water Quality Standard for THM in drinking water is 0.100 mg/L.
What kind of minerals can be found in drinking water?
Arsenic is a natural occurring element that is found in rocks. Arsenic can be found in the water from the breakdown of rocks or from deposits of mining tailings. The two most common exposures to arsenic is through food and water. Absorption through the skin is minimal so it is safe to use water containing arsenic for bathing, hand washing, and laundry.
Long term exposure may increase risk of certain types of cancers and changes to skin pigmentation. Short term exposure to very high levels of arsenic can lead to diarrhea, vomiting, skin rash, and numbness.
The Ontario Drinking Water Quality Standard for arsenic in drinking water is 0.025 mg/L.
Lead in drinking water is normally found in homes built before the mid-1950s as it was common practice to use lead pipes during construction.
If you suspect that you have lead pipes in your home, you should run the water for at least 5 minutes if the tap water has been sitting for longer than 6 hours. Lead is a health concern for children under the age of six and pregnant women. The Ontario Drinking Water Quality Standard for lead in drinking water is 0.010 mg/L.
Sodium is one of the most common naturally occurring elements in the earth. Sodium in drinking water is only a health risk to individuals that are required to be on a low sodium diet. If you have high levels of sodium in your drinking water and you are required to be on a low sodium diet, a different source of water is recommended.

Uranium is a naturally occurring element found in soil and rock formations. Levels of uranium in drinking water can vary depending on the type of rock formations. Showering and bathing in water with uranium is not a health hazard. Uranium in drinking water does not pose an immediate health effect, however, over time, kidney damage may occur. The Ontario Drinking Water Quality Standard for Uranium in drinking water is 0.020 mg/L. 

For more information please contact a Public Health Inspector during work hours at your local health unit office.

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