Drinking water should be tested for arsenic to make certain that unsafe levels of this poisonous substance are not present.
What is arsenic?
Arsenic is a natural element, a mineral naturally present in soil and rock, and found in water and living things. The Wisconsin Department of Health Services “Arsenic” fact sheet describes it as a “silver-gray or white brittle metal,” with no odor and little taste (dhs.wisconsin.gov). Though it is perhaps best known as a poison, arsenic has many industrial uses including insecticides, electronics and lasers (“Arsenic,” ucc.ie).
In places where there is arsenic in the earth’s crust, it can be dissolved in surface water and underground aquifers, and it can therefore be present in drinking water.
Arsenic in well water
Arsenic is only a problem in well water in certain areas because the mineral is not evenly distributed geographically. In addition to natural sources, arsenic can enter the environment through industry or agriculture. Very low levels of arsenic are not a problem, but higher levels mean that the water should not be used for drinking, and very high levels make the water unusable for all domestic purposes.
The Wisconsin Department of Health defines allowable limits of arsenic in water:
- Less than ten parts per billion (.01 parts per million or 10µg/L) is safe for all uses.
- More than ten parts per billion but less than 500 parts per billion (.5 parts per million) is not safe to drink, but can be used for other things, including washing food and dishes.
- More than 500 parts per billion is unsafe for household use.
Although the definition of acceptable allowable limits may vary from place to place, the values given above are fairly standard and conform to WHO guidelines.
Arsenic symptoms
According to Health Canada (“Arsenic in Drinking Water,” hc-sc.gc.ca), the major health concern in people who have long term exposure to arsenic is cancer, however there are other symptoms of arsenic poisoning, both acute and chronic.
Short term exposure to very high levels of arsenic can cause:
- stomach flu-like symptoms
- numbness, tingling and/or pain in the extremities
- skin symptoms including flushing, rashes, and thickening of the skin on the palms and soles
- muscle pain
- weakness
- loss of movement and sensation
Over the long term, exposure to high levels of arsenic results in:
- stomach flu–like symptoms
- thickened and discoloured skin
- damage to blood vessels and heart rhythm irregularities
- numbness in the extremities
- low blood cell counts
Arsenic removal
When levels of arsenic are too high in well water, one must either avoid consuming the water, or install a system to remove the metal from the water. Home devices for arsenic removal that meet safety standards are certified by NSF International (NSF)/American National Standards Institute (ANSI).
Levels of arsenic in well water can fluctuate, so for wells in areas where this substance is detected or suspected, regular periodic testing is recommended.
Rosemary Drisdelle - Rosemary Drisdelle has been published many times as a nonfiction writer and several times as a poet. Her first book, Parasites: Tales of ...
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