Barium

Barium (Ba) is a metal that occurs naturally in the Earth's crust. Many of us are familiar with barium because it's used in medical procedures, most notably when X-rays are taken of the gastrointestinal tract. In that situation, it is carefully administered under medical supervision and no harm is done to the person taking it.

However, barium is toxic and if it is found in high levels in a water supply - which can happen in situations where industrial runoff has occurred - then it is dangerous. Barium is used in plastics manufacturing, in oil well drilling, in the manufacturing of brakes, acoustic foam, and root canal filling. Given the many good uses for barium and the many ways that it can also harm us, it's obvious that it's important to monitor the presence of barium in our surroundings.

Barium, when found in drinking water, is not associated with increased risk of cancer or birth defects, but it can cause breathing difficulties. Other medical problems associated with ingesting barium at abnormally high levels include high blood pressure, alterations in heart rhythm patterns, stomach problems, swelling of vital organs such as the brain and liver, and heart or kidney damage.

The EPA has set the Maximum Contaminant Level Goal (MCLG) at 2 parts per million (ppm). This number was used to create a standard which the EPA terms a Maximum Contaminant Level (MCL), also 2 ppm. Should barium be discovered in a water supply at greater levels than this, the local water supplier is obligated to notify the public, according to the EPA, via media including newspapers, radio, and TV.