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.

Atmospheric radionuclides transported to Fukuoka, Japan remote from the Fukushima Dai-ichi nuclear power complex following the nuclear accident.

Radionuclides were detected from the Fukushima nuclear accident at Fukuoka, Japan, 1000 km west of the Fukushima Dai-ichi nuclear power complex. Iodine-131 was first detected 3 d after the accident, indicating that it was probably transported dispersively because of local meteorological conditions, and not global air circulation. The maximum concentrations, 5.

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.

Uptake of deuterium by dead leaves exposed to deuterated water vapor in a greenhouse at daytime and nighttime.

Dead leaves were exposed to deuterated water vapor (D(2)O) as a substitute of tritiated water (HTO) in a greenhouse at daytime and nighttime to examine uptake and release of tritium by dead leaves because they cover a wide area of the forest floor and are therefore a major target material to be exposed when HTO is atmospherically derived to the forest. The dead cedar needles showed faster uptake and faster release rates during and after the exposure than the fresh ones, and the equilibrium concentration of the dead cedar needles was about two times higher than the fresh ones, indicating a quick response and a high buffering potential of dead leaves. The relation between uptake of D(2)O and number of stoma was examined for dead deciduous leaves; the species with larger number of stoma accumulated more D(2)O at the daytime and nighttime exposures.

Biologically induced Po emission from fresh water.

Behavior of Po in fresh waters was examined in laboratory culture experiments using fresh water collected from a small pool, Xi river and Xiqing lake, showing formation of volatile Po compounds followed by emission to air. Addition of tryptone to the fresh water cultures increased the emission of Po considerably along with a growth of microorganisms, suggesting a connection of chemoheterotrophs to Po emission. Participation of photoautotrophs was also considered because Po emission was increased when NaHCO3 was added to the fresh water cultures.

Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.

We observed biologically mediated emission of Po from culture solution inoculated sea sediment extract and incubated under natural light/dark cycle condition or dark condition the emitted Po compound would be lipophilic because of effective collection in organic solvent. Sterilization of the culture medium with antibiotics or CuSO4 completely suppressed growth of microorganisms and resulted in no emission of Po, indicating biological activity of microorganisms is responsible for formation and emission of volatile Po compound. Po emission also occurred when seawater was used as a culture medium.

Overview of tritium: characteristics, sources, and problems.

Tritium has certain characteristics that present unique challenges for dosimetry and health-risk assessment. For example, in the gas form, tritium can diffuse through almost any container, including those made of steel, aluminum, and plastics. In the oxide form, tritium can generally not be detected by commonly used survey instruments.

[Tritium and carbon-14 concentrations around an incinerator for radioactive liquid scintillator waste].

Activity measurements of 3H and 14C in several environmental samples around the incinerator for radioactive liquid scintillator waste at the Radioisotope Center, Kyushu University were carried out to estimate their levels. It was indicated that 3H and 14C concentrations in the atmosphere at 1 m from the outlet were about 0.2% of those estimated at the outlet, respectively.

[Radioactive and stable cobalt concentrations in mussel in Kyushu islands, Japan].

Two kinds of mussel, Septifer virgatus and Mytilus edulis, were collected from Kyushu island, Japan, in order to elucidate a background level of 60Co, which is one of the most significant radionuclide for environmental monitoring around a nuclear power plant. The mussels were collected from 7 locations in 1983 and classified 2 or 3 groups depending on their shell size at each location. Activities of 60Co were measured by a low-background beta counter after purified by means of chemical separation and electrodeposition.

Vial effect and background subtraction method in low-level tritium measurement by liquid scintillation counter.

Counting efficiencies of individual Teflon vials used in low-level tritium measurement by a liquid scintillation counter were investigated. The efficiency observed was fairly varied among vials in spite of being prepared in the same way. And the plots of the efficiency vs the external standard ratio give a straight line.

Determination of 222Rn by liquid scintillation counter combined with p-xylene extraction technique.

222Rn Determination method by liquid scintillation counter after extracting 222Rn with p-xylene was studied. It was confirmed that extraction of 222Rn with p-xylene proceeds quantitatively. Several experimental conditions for the counting such as scintillator content in p-xylene, the quencher effect, the zero level extrapolation method and 3-channel counting method were examined.