Variation analysis of atmospheric Be activity concentrations with respect to precipitation.

Beryllium-7 activity concentrations in the atmosphere and precipitation were continuously measured every day between April 2011 and December 2015 in Dazaifu, western Japan. The measured data were quantitatively analyzed to determine the precipitation-induced variation in Be activity concentrations. The average concentrations on nonprecipitation and precipitation days were 5.

TRITIUM IN THE ENVIRONMENT.

Environmental tritium are natural and anthropogenic origins, the distribution has spread in atmosphere, hydrosphere and biosphere as a variety of chemical forms. The natural tritium is produced by nuclear reactions of neutron with N and O in the upper atmosphere, the production rate changes with 11-year cycle of the solar activity. The production and radioactive decay of natural tritium is balanced on the whole earth, results in the inventory of about 1 EBq.

Analysis of Factors Contributing to the Increase in Be Activity Concentrations in the Atmosphere.

In March 2013, increased Be activity concentrations in the atmosphere were observed for successive days in Dazaifu, western Japan. The daily Be activity concentration ranged from 0.93 to 14 mBq/m, with a monthly average of 8.

Cosmogenic Be: Particle size distribution and chemical composition of Be-carrying aerosols in the atmosphere in Japan.

The particle size distributions of airborne aerosols with Be were measured using cascade impactors at Dazaifu, a city in western Japan, in 2018 to observe their seasonal variation. Beryllium-7 was found to be adsorbed to aerosols with a particle size of less than 2.1 μm; in general, particles sized 0.

Tritium concentrations in the atmospheric environment at Rokkasho, Japan before the final testing of the spent nuclear fuel reprocessing plant.

This study aimed at obtaining background tritium concentrations in precipitation and air at Rokkasho where the first commercial spent nuclear fuel reprocessing plant in Japan has been under construction. Tritium concentration in monthly precipitation during fiscal years 2001-2005 had a seasonal variation pattern which was high in spring and low in summer. The tritium concentration was higher than that observed at Chiba City as a whole.

An improved method for 85Kr analysis by liquid scintillation counting and its application to atmospheric 85Kr determination.

Atmospheric (85)Kr concentration at Fukuoka, Japan was determined by an improved (85)Kr analytical method using liquid scintillation counting (LSC). An average value of 1.54 +/- 0.

Isotopic evidence in tree rings for historical changes in atmospheric sulfur sources.

Little is understood about the usefulness of sulfur isotopic ratios (sigma 34S) in tree rings because the sulfur content in rings is generally insufficient for analysis using conventional methods. We present sigma 34S values of the water-soluble and the organically bound sulfur fractions in rings of coniferous trees grown in Japan, analyzed using a large-volume oxygen bomb. Comparing the sigma 34S values of the organically bound fraction in tree rings with past atmospheric sulfur concentrations and with those of their sources, we find clear evidence that the sigma 34S values of the organically bound fraction in the rings are dependent upon the values of the atmospheric sulfur sources.