Concentration and particle-size distribution of uranium and some trace elements in airborne dust collected in Tsukuba.

Uranium and some other trace elements were determined in the size-separated airborne dust collected in Tsukuba with an Andersen-type high-volume cascade impactor. The fission track method and the instrumental neutron activation method were applied to the determination of uranium and other elements, respectively. Selenium, antimony, arsenic and zinc were found to be rich in particulates of smaller size, while scandium, iron and cobalt showed a reverse trend, depending on their main origins, i.e. whether industrial or terrestrial. Uranium was distributed in both the larger and smaller particles to the same extent, suggesting that it is derived from both the terrestrial and artificial sources.