Potassium iodide is a salt that has many applications in various industries. It is used to chemically synthesize silver iodide, a substance used in photography that initiates a chemical reaction when exposed to light. Potassium iodide is also used as a food additive in animal feed, and when prepared as a saturated solution it has several uses in medicine. For instance, saturated potassium iodide is an emergency treatment for radiation exposure.
Description
Saturated potassium iodide, or SSKI, is a liquid solution that contains potassium iodide and plain water. As the term implies, the solution is saturated, meaning that the point in which the water can no longer absorb the amount of potassium iodide in the solution has been reached. As a result, particles of potassium iodide are seen resting at the bottom of the liquid.
Chemical Properties
According to the Material Safety Data Sheet prepared by the U.S. Department of Environmental Health & Safety, potassium iodide is an odorless, white crystalline salt with a pH between 7 and 9 and a solubility of 140 g per 100 g of water. It is a stable material under normal use and storage. However, it turns yellow with prolonged exposure to air and degrades in the presence of light, moisture and various other chemicals, such as chlorine and fluorine distillates, acids and metallic salts.
Pharmaceutical Uses
According to Johns Hopkins University, saturated potassium iodide is used to counter the effects of an enlarged thyroid in people with Graves' disease and to reduce the risk of excessive bleeding while undergoing a thyroidectomy. The solution is also administered to people with hyperthyroidism, or overactive thyroid. Under extreme circumstances in what is described as a thyroid "storm," saturated potassium iodine is given to temporarily suppress the secretion of thyroxine, one of the main thyroid hormones.
SSKI is also administered following exposure to radiation to block the uptake of radioactive iodine by the thyroid. In fact, the U.S. Federal Drug Administration estimates that 10.5 million children and 7 million adults were treated with saturated potassium iodide after the 1986 Chernobyl nuclear reactor disaster.
Saturated potassium iodine is also used to treat sporotrichosis, a fungal infection of the skin also known as rose gardener's disease. However, in a 2009 Cochrane review, Si-Liang Xue and fellow researchers at Sichuan University in China concluded that clinical evidence of the effectiveness of this therapy is currently lacking.
Storage and Handling
According to the Material Safety Data Sheet, or MSDS, saturated potassium iodine should be kept stored in a tightly sealed container away from light, moisture and heat. Long-term storage is not advisable due to the risk of the material degrading. Proper handling requires the use of personal safety gear, such as an apron, gloves, safety goggles and a particulate respirator, if an exhaust ventilation hood at the workstation is not available.
Potential Health Risks
The MSDS states that SSKI may irritate the throat and lungs if inhaled and the skin with direct contact. Ingestion, particularly in large amounts, results in a condition called "iodism," which is characterized by skin rash, lethargy, weight loss and headache. Otherwise, this material has an overall health, contact and reactivity rating of 2, which is moderate.
