The Hanford site represents two-thirds of the United States’ high-level radioactive waste by volume. Nuclear reactors line the riverbank at sources of groundwater contamination pdf Hanford Site along the Columbia River in January 1960.
As of 2013, the Fukushima nuclear disaster site remains highly radioactive, with some 160,000 evacuees still living in temporary housing, and some land will be unfarmable for centuries. The difficult cleanup job will take 40 or more years, and cost tens of billions of dollars. Such contamination presents a hazard because of the radioactive decay of the contaminants, which emit harmful ionising radiation such as alpha particles or beta particles, gamma rays or neutrons. The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body.
It is important to be clear that the contamination gives rise to the radiation hazard, and the terms “radiation” and “contamination” are not interchangeable. Contamination may affect a person, a place, an animal, or an object such as clothing. Following an atmospheric nuclear weapon discharge or a nuclear reactor containment breach, the air, soil, people, plants, and animals in the vicinity will become contaminated by nuclear fuel and fission products.
A spilled vial of radioactive material like uranyl nitrate may contaminate the floor and any rags used to wipe up the spill. Cases of widespread radioactive contamination include the Bikini Atoll, the Rocky Flats Plant in Colorado, the Fukushima Daiichi nuclear disaster, the Chernobyl disaster, and the area around the Mayak facility in Russia. Global airborne contamination Atmospheric nuclear weapon tests almost doubled the concentration of 14C in the Northern Hemisphere. Plot of atmospheric 14C, New Zealand and Austria.
The New Zealand curve is representative for the Southern Hemisphere, the Austrian curve is representative for the Northern Hemisphere. Radioactive contamination can be due to a variety of causes.