Tailing is a designation for the sludge residues derived from the ore preparation which arise during the production of uranium after its separation from the accompanying screed. The amount corresponds directly to the mass of ore processed, meaning that many million metric tons of weakly radioactive tailings are annually generated in the worldwide production of uranium. These are stored at the location of their original generation, i.e. at the mines or processing centers in large basins, mostly separated by dams. As a result of several dam breaches in the past, strict regulations apply to the design, construction and operation of such retention facilities today.
A toxin is understood to be a poisonous substance of biological origin. The scientific discipline engaged in the research of such poisons, their effects and their treatment is toxicology.