IODINE (I) 126.9 Atomic Weight
Iodine is a relatively rare element, occurring sparingly in sea water to the extent of approximately 50 milligrams per ton of water. Appreciable quantities are also found in a number of natural brines and in saltpeter and nitrate deposits. Dispersed as a trace element in rocks and soil, it is not sufficiently concentrated to form independent minerals. Iodine occurs in very small amounts in plants and animals, but very abundantly in seaweed. It is an essential micro-constituent in the human body, most of which in concentrated in the thyroid gland. This gland secretes Iodine-bearing hormones that are essential for maintaining normal metabolism in all the body’s cells. Because of its germicidal effects, Iodine is used in many areas of medicine, including diagnostic work in locating tumors and in radiology.
In plants, it serves in support of the plant’s immune system as a natural antiseptic in maintaining resistance to invading foreign bacteria. It is also used as an additive to a number of animal feeds and dietary supplements. Excessive amounts of Iodine are toxic and may cause serious damage to cell tissues.