Iodine in biology air should not exceed 1 mg/m³ (eight-hour time-weighted average). When mixed with ammonia and water, elemental iodine forms nitrogen triiodide, which is extremely shock-sensitive and can explode unexpectedly. Excessive iodine intake presents symptoms similar to those of iodine deficiency. Commonly encountered symptoms are abnormal growth of the thyroid gland and disorders in functioning, as well as in growth of the organism as a whole. Iodide toxicity is similar to (but not the same as) toxicity to ions of the other halogens, such as bromides or fluorides. Excess bromine and fluorine can prevent successful iodine uptake, storage and use in organisms,
Isotopes of iodine and 1970s reached about 10). I differs from Cl in that its half-life is longer (15.7 vs. 0.301 million years), it is highly biophilic, and occurs in multiple ionic forms (commonly, I and IO), which have different chemical behaviors. This makes it fairly easy for I to enter the biosphere as it becomes incorporated into vegetation, soil, milk, animal tissue, etc. Of the many isotopes of iodine, only two are typically used in a medical setting: iodine-123 and iodine-131. Since I has both a beta and gamma decay mode, it can be used for radiotherapy or for imaging. I, which