Since iodine is needed in only trace amounts, getting too much of it can cause health problems as well. American pathologist David Marine is credited with getting the ball rolling toward putting iodine in salt.
On his first day as a new doctor in Cleveland in , Marine was immediately struck with how many people, and even dogs, were walking around with swollen necks, indicative of a widespread goiter problem. In fact, the condition had become so pervasive that a large stretch of land from the Rockies to the Great Lakes region to western New York was known as the "goiter belt.
After exploring a few hypotheses and coming up empty-handed, Marine began experimenting with iodine supplements. He conducted one of the first ever large-scale human experiments by giving miniscule doses of iodine to 2, healthy goiter-free students in Akron, Ohio.
A control group of 2, healthy students were not given any iodine but were still closely monitored. The results were astounding. Of the 2, who received iodine, only five eventually developed a thyroid condition, compared to individuals in the control group. Although there had been some existing research at the time linking iodine to the thyroid gland, Marine conclusively established that iodine was indeed an essential element for life and one in whose absence could result in severe health problems.
Marine's important findings led to the first iodized salt being sold in the United States in Soon after its introduction, iodized salt had largely eliminated the widespread goiter deficiency. Live Science. Traci Pedersen. Potassium iodide KI is used to make photographic film and, when mixed with iodine in alcohol, as an antiseptic for external wounds. A radioactive isotope of iodine, iodine, is used to treat some diseases of the thyroid gland.
Care should be taken in handling and using iodine. It can burn the skin and damage the eyes and mucous membranes. Pure iodine is poisonous if ingested. Estimated Crustal Abundance : 4. It gets its name from the Greek work iodes , meaning violet. Tags: science chemical element chemistry goitre iodine periodic table salt trace element.
Recent stories from Elemental Zirconium - shape-shifting time capsule Zinc - more useful than you realise Yttrium - here's that village Ytterby again Ytterbium - yet another element named after Ytterby Xenon - a stranger in search of strange particles. Large quantities of iodine can be dangerous because the thyroid gland will labour too hastily.
This affects the entire body; it causes disturbed heartbeats and loss of weight. Elemental iodine, I 2 , is toxic, and its vapour irritates the eyes and lungs. The maximum allowable concentration in air when working with iodine is just 1 mg m All iodides are toxic if taken in excess. Iodine is one of the radionuclides involved in atmospheric testing of nuclear weapons, which began in , with a US test, and ended in with a Chinese test.
It is among the long-lived radionuclides that have produced and will continue to produce increased cancers risk for decades and centuries to come.
Iodine increases the risk of cancer and possibly other diseases of the thyroid and those caused by thyroid hormonal deficiency. Iodine in air can combine with water particles and precipitate into water or soils.
Iodine in soils will combine with organic matter and remain in the same place for a long time. Plants that grow on these soils may absorb iodine.
Cattle and other animals will absorb iodine when they eat these plants. Iodine in surface water will vaporize and re-enter the air as a result. Humans also add iodine gas to the air, by burning coal or fuel oil for energy. But the amount of iodine that enters the air through human activity is fairly small compared to the amount that vaporizes from the oceans.
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