Iodine and radiation

The Royal Society of Chemistry is warning against panic buying of potassium iodide tablets as a protective agent against exposure to radioactive iodine. It also cautioning cautioned against scaremongering regarding the potential effect of explosions at the Fukushima nuclear plant, saying that any comparisons with the 1986 Chernobyl disaster are unfounded.

Radioactive iodine (I-131) forms as a by-product in many nuclear reactors.

But, iodine itself is an essential constituent of a healthy diet in tiny amounts as it forms a component of thyroid hormones. The element is is absorbed by the human body into the bloodstream where it is taken up by the thyroid and incorporated into these hormones. Exposure to a radioactive isotope of iodine, and subsequent concentration in the thyroid, can therefore result in damage to the thyroid.

It is thought that by ingesting potassium iodide tablets, a high dose of non-radioactive iodine can overwhelm the uptake mechanisms and so reduce the amount of radioactive iodine that might reach the thyroid. Of course, taking potassium iodide tablets after exposure to radioactive iodine will still have some protective effect.

The RSC reports that US citizens have been panic buying potassium iodide tablets, perhaps on the back of a fraudulent map scurrilously claiming that a radiation cloud is heading for the western coast of the USA. One supplier says it has sold 250,000 “anti-radiation pills” since news of the Japanese nuclear reactor incidents broke.

“For the US to be affected, an explosion would have to occur that was powerful enough for radioactive iodine to reach the upper atmosphere, get picked up by the jet stream then carried to the United States,” says Brian Carter, environmental sciences programme manager at the RSC. He adds that that there is a plentiful global supply of iodine and that the people who do need the tablets are those in and around the exclusion zone in Japan. “Supply is incredibly unlikely to be an issue, provided that people are not driven into buying and using the pills by scaremongering,” he adds.

More on RSC site.

4 thoughts on “Iodine and radiation”

  1. Absolutely right people in North America (or Europe!) don’t need KI right now because of the Japan crisis. But you soft-pedaled the evidence in favor of KI prophylaxis. It is not merely “thought” that taking prophylactic iodine is protective, it has been clearly documented in the aftermath of the Chernobyl accident by the experience in Poland. In response to the detection of elevated levels of radioiodines on April 27 and 28, 1986 in Poland (2-3 days post-event), 18 million doses of iodide were distributed and no additional thyroid cancers were found. The US Food and Drug Administration, US National Academies, World Health Organization and numerous other bodies have determined that KI prophylaxis is safe and effective and should be part of comprehensive emergency planning around nuclear power plants.

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