ABSTRACT
The radioactive decay of uranium through radium leads to the release of radon, or more precisely the isotope radon-222, which further decays to a series of radioactive isotopes of polonium, bismuth, and lead. Uranium in rock is the source of the high radon levels in uranium mines. There are trace amounts of uranium in many kinds of minerals, however, so that a high radon emanation from rock can occur also in other types of mines, such as iron and zinc-lead mines. Radon levels in homes depend on building material and, more important, on leakage from the ground. A problem in epidemiology is always to obtain accurate information on exposure, indeed a characteristic feature of environmental epidemiology. Inhaled radon reaching the fat cells in the bone marrow in contrast to the radon progeny deposited in the lungs, was thought to be responsible for the induction of myeloid leukaemia.
