Extraction ratios and behavior of uranium in atmospheric particulates and surface soils.

Abstract

The purposes of these studies are to estimate the influence of uranium in environment on the inhabitant's health and to develop the environmental radioactivity monitoring techniques. The extraction ratios of uranium in surface soils and atmospheric particulates, and the distribution of uranium in atmospheric particulates have been investigated by instrumental neutron activation analysis and alpha ray spectrometry. The extraction ratios of uranium in surface soils with HNO3 were ranged from 30% to 60%. The extraction ratios of uranium in atmospheric particulates were almost the same as that of HNO3 or HCl-H2O2, 70% to 80%. By the evaluation of the total uranium contents in surface soils and atmospheric particulates, it was possible to correct the determination values of uranium depending upon acid extraction ratios. Higher concentration of uranium in atmospheric particulates at the daytime was observed than those at the night. At the rainy day, both concentrations of dusts and uranium in atmospheric particulates decreased. Activity ratios of 234U/238U in atmospheric particulates were equal to those in surface soils at the daytime, the night and the rainy day. It was estimated that 80% to 93% of uranium in atmospheric particulates collected in Yokohama city in Kanagawa Prefecture were derived from soils.