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What is it and where is it found?

Arsenic is a naturally occurring element found in the earth's crust. As water flows through certain rock formations, it can dissolve arsenic and carry it into underground aquifers, streams or rivers that are then used for drinking water sources. Arsenic is also a by-product of certain mining and agricultural practices, and is in treated wood used for specific construction purposes.

How do people come into contact with it?

Most people in Oregon come into contact with arsenic by drinking contaminated groundwater in areas where it is naturally occurring.

Arsenic is in certain pesticides and fertilizers. The agricultural run-off can then carry arsenic and other contaminants into underground aquifers, streams or rivers that are used for drinking water sources.

Touching, sawing, or burning arsenic-treated wood is another way people ingest arsenic. Treated wood has easily recognizable marks throughout the length of the boards. To be sure, check the label or ask the retailer where purchased.

Certain jobs can increase a person’s contact with arsenic, such as lead or copper smelting, wood treating, or pesticide application.

What are the health concerns?

Drinking water contaminated with arsenic above set guidelines puts your health at risk. The Environmental Protection Agency has set a drinking water standard of no more than 10 parts per billion of arsenic. This is roughly equal to ten drops of arsenic in an Olympic-sized swimming pool. 

Health effects can depend on how much arsenic is in the water, how long a person drinks the arsenic contaminated water, as well as a person’s individual susceptibility to arsenic.  Below are some basic health symptoms of arsenic poisoning:

Acute (sudden) arsenic poisoning may include symptoms of stomach pain, nausea, vomiting and diarrhea. This usually only happens when someone swallows a large amount at one time.

Chronic (long-term) symptoms can be the result of drinking low levels of arsenic over a long period of time (years), and can include:

  • Thickening and discoloration of the skin;
  • Numbness of the hands and feet;
  • Learning disabilities;
  • Lowered intelligence;
  • Certain types of neurobehavioral problems in children (having to do with the way the brain affects emotion, behavior and learning).
  • Heart, lung, or liver disorders and diabetes;
  • Immune system disorders (the body’s system that helps fight infection);
  • Reproductive system disorders (the body’s system concerned with sexual reproduction);
  • Cancer of the skin, bladder, lungs, liver, and prostate.

What can I do to protect myself, my family, or my employees?

Currently, the most heavily exposed people in the United States are in those industries that use arsenic, including:

  • Carpentry involving CCA pressure-treated lumber;
  • Copper or lead smelting;
  • Electronics manufacturing industry;
  • Pesticide application.

For people whose jobs require they work around arsenic, learn about the Occupational Safety & Health Administration (OSHA) guidelines.

If you use well water for drinking and cooking, have your water tested by a certified laboratory.  Water with arsenic levels above 10 parts per billion is not safe for drinking, cooking, or washing food.

If you have arsenic in your water, boiling will not remove it. In fact, boiling the water can further increase the level the arsenic. This is true for all heavy metals.

There are water filters designed to remove arsenic from water, however the type of filter you decide to use will depend on several factors:

  • The level of arsenic in your water;
  • Other factors about your water (pH level, amount of iron, etc.);
  • The level of proper maintenance.
  • If you are considering a filtration system to remove arsenic, make sure you buy one that is certified by NSF International.
  • When buying pressure-treated wood for construction projects, always wear gloves, a mask and protective clothing. Take off work clothes before entering the house so that you don’t contaminate your living area.
  • Do not use treated wood for children’s play structures, places where animals are raised for food, garden beds or compost bins.

What's being done to protect public health?

Federal regulations require that public drinking water systems have arsenic concentrations below 10 parts per billion.

As of 2009, Oregon law requires arsenic testing in addition to nitrates and bacteria when there is a real-estate transaction involving properties with domestic wells.

Where can I get more information?

Agency for Toxic Substances & Disease Registry, ToxFAQs™ for Arsenic

Environmental Protection Agency, Arsenic in Drinking Water

Occupational Health & Safety Administration, Arsenic

Oregon Health Authority's Drinking Water

Oregon State University, Well Water Program