A radioactive isotope of the element iodine. During the 1950s and early 1960s, iodine-131 was considered a major health hazard to humans. Along with cesium-137 and strontium-90, it was one of the three most abundant isotopes found in the fallout from the atmospheric testing of nuclear weapons. These three isotopes settled to the earth's surface and were ingested by cows, ultimately affecting humans by way of dairy products. In the human body, iodine-131, like all forms of that element, tends to concentrate in the thyroid, where it may cause cancer and other health disorders. The Chernobyl nuclear reactor explosion is known to have released large quantities of iodine-131 into the atmosphere.

See Also

Radioactivity