Element collecting from hydrogen to bismuth (except the radioactive technetium and promethium) are collected, with the exceptions of the extremely long-lived thorium and uranium. It is possible to source other radioactive elements, such as radium (usually in the form of radium sulphate as part of luminescent paint on antique watch hands), tritium - a radioactive isotope of hydrogen, americium (in the form of radioactive buttons containing 0.29 micrograms of americium extracted from older smoke detectors), and technetium. Element collecting Element collecting is the hobby of collecting the chemical elements. Many element collectors simply enjoy finding peculiar uses of chemical elements. Others enjoy
Depleted uranium US tank armor. The use of DU in munitions is controversial because of concerns about potential long-term health effects. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by exposure to uranium, a toxic metal. It is only weakly radioactive because of its long radioactive half-life (4.468 billion years for uranium-238, 700 million years for uranium-235; or 1 part per million every and years, respectively). The biological half-life (the average time it takes for the human body to eliminate half the amount in the body) for uranium is about 15 days. The aerosol or