Iodine-131 (usually in the chemical form of iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine, where it is kept for periods longer than this isotope's radiological half-life of eight days.
Magma is composed of molten rock and is stored in the Earthâs crust. Lava is magma that reaches the surface of our planet through a volcano vent. Lava flow, Hawai. Courtesy of the U.S. Geological Society.agma is composed of molten rock and is stored in the Earthâs crust. Lava is magma that reaches the surface of our planet through a volcano vent. Lava flow, Hawai. Courtesy of the U.S. Geological Society.
Top definition. lava. Lava is molten rock that originated from the mantle of a planet. Usually extracted through volcanos either on land or underneath water. Not to be confused with magma, which is molten rock that is still under the planets surface. Magma turns into lava after it erupts onto the surface.