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Natural tritiated moisture levels in air vary with atmospheric pressure.

Natural HTO levels in air at ground level were measured on 100 days during 1979-80. Levels of between 6-140 Bq m-3 of air were observed and found to have a correlation with atmospheric pressure. Lithium chloride was used to absorb moisture, which was then recovered by distillation with xylene prior to liquid scintillation counting using a Triton X-100 cocktail. HTO in the air of a reactor hall and HTO in seawater were also measured by this method.

Air Pollution, Radioactive↗

Analysis of tritiated water vapor by non-volatile liquid scintillant sorbent.

The quantitative analysis of tritiated water vapor in air was investigated by sorption into a non-volatile liquid scintillant solution sorbent of silicone oil. The activity of the beta-ray from the sorbed tritiated water vapor, 10(-7) microCi/mL in air, was directly measured with the help of the scintillator solution which also served as the sorbent. It was found that the variation of the partial vapor pressure of tritiated water in air was proportional to the sorbed amount in the liquid scintillator sorbent from the vaporized tritiated water. The relation was also expressed as a sorption isotherm equation and was compared to the Langmuir adsorption isotherm supporting the suggested adsorption by solid adsorbent.

Adsorption↗

99Tc in surface air samples during the years 1965-1967.

In this work, 99Tc activities in atmospheric filters taken during the years 1965, 1966 and 1967 are measured on a monthly or bimonthly basis. The results show a clear yearly pattern of the activities with a maximum below 3 mBq/1000 m3 at the end of each summer, probably related, in a non trivial way, to meteorological factors. Our atmospheric 99Tc data add a more detailed structure to previously published fallout curves.

Air Pollutants↗

Chromosome aberrations in nuclear power plant workers: the influence of dose accumulation and lymphocyte life-time.

Chromosome analyses were performed in blood lymphocytes of 22 nuclear power plant workers with a mean accumulated radiation dose of 390 mSv (270-530 mSv). Nineteen workers had received 300 mSv 4-16 years prior to sampling. The frequency of dicentrics and ring chromosomes (1.75 x 10(-3)) was significantly elevated as compared to a control group (0.58 x 10(-3)). Based on the initial slope of an in vitro 60Co gamma-ray curve, a biological dose estimate of only 110 mSv was derived. This can be interpreted in terms of an "equivalent-acute" dose at the time of blood sampling which can be derived by weighting annual doses during working periods of 12-30 years for a mean life-time m of lymphocytes. The annual doses were additionally weighted for a uniform distribution during a whole year. Using m = 10 years, a mean "equivalent-acute" dose of 90 mSv (64-157 mSv) is obtained, which compares more closely to the biologically estimated dose than 20 mSv (7-71 mSv) based on m = 4.3 years.

Adult↗

Search for correlation of radon levels and incidence of salivary gland tumors.

Studies were undertaken to determine if there is a statistical correlation between radon levels and the incidence of salivary gland tumors because of high levels of radon in Pennsylvania. In Part I of the study, the incidence of minor salivary gland tumors accessioned by Temple University, Emory University, and University of Southern California from 1986 to 1988 were correlated with average radon levels in the three locations with the use of standard statistical analyses. In Part II, the occurrence of malignant salivary gland tumors was obtained for each of the 67 counties in Pennsylvania from 1986 to 1988 and correlated statistically with radon levels and population figures in each of those counties. A statistically significant correlation between radon levels and incidence of salivary gland tumors could not be demonstrated in either case.

Air Pollutants, Radioactive↗

Radionuclides in natural terrestrial ecosystems.

p6osystems to be found in the maritime temperate zone are described. The part played by vegetation, animals and soils in the distribution and movement of radionuclides is discussed, with particular reference to natural systems. Biomass activities have been compiled for 137Cs and 239 + 240Pu in woodland and moorland ecosystems. The data indicate that these ecosystems are more effective at intercepting and retaining radionuclides than are agricultural systems and that many undisturbed soils function as efficient sinks.

Air Pollution, Radioactive↗

Uptake of 226radium and 228radium by the lichen genus Umbilicaria.

The 226Ra and 228Ra content of the lichens Umbilicaria cylindrica, U. deusta, U. murina and U. hirsuta has been determined as a function of the growth altitude above sea level, based on data derived from material collected from localities in southwest Poland. These data are interpreted as graphs and formulae to show the influence of environmental factors, particularly altitude, on the concentration of 226Ra and 228Ra, and the coefficients of accumulation calculated.

Air Pollutants↗

Investigations on fly-ash and soil samples in the environment of a coal-fired power plant.

In the main wind direction of a coal-fired power plant dust and soil samples have been collected to analyse the content of fly-ash coming from the power plant. The fly-ash particles are spherical and contain the natural radionuclides mainly Ra-226, Pb-210, Po-210 and K-40 in a higher concentration when compared with the original coal. The investigation of soil samples results in increased Pb-210 and Po-210 concentrations when compared with the natural environment. By presence of spherical particles in dust and soil samples the power plant can be identified as the emitter.

Air Pollutants↗

Radon adsorption on activated carbon and the effect of some airborne contaminants.

The adsorption and desorption of radon on five types of activated carbon and the effect of various airborne contaminants on the adsorption process was studied, the dynamic adsorption coefficient for the carbon samples tested was found to range from 2.4 +/- 0.2 to 7.1 +/- 0.71 g-1. Iso-octane was found to reduce the dynamic adsorption coefficient significantly.

Adsorption↗

The propagation of the Chernobyl 131I impulse through the air- grass- animal- milk pathway in northwestern Greece.

A three-compartment (air- grass-milk) milk contamination model for 131I has been applied to atmospheric, grass and milk data, following the April 1986 nuclear accident at Chernobyl. Samples of ovine and bovine milk collected daily by a large dairy company in Ioannina (northwestern Greece), throughout the month of May 1986 have been employed. The contamination impulse in the area, which provides the input to the model, has been approximated by a first order gamma-variate curve. Transfer rates and decay constants have been extracted by fitting predictions of the model independently to each set of data (air, grass and milk). All model parameters obtained from more than one set of data show remarkable consistency. These parameters are used to calculate the transfer coefficients fm for the transport of radioiodine at equilibrium for sheep and cows.

Accidents↗

The environmental half-lives and mean residence times of contaminants in dust for an urban environment: Barrow-in-Furness.

Radiocaesium contamination of dusts from external (road and school yards) and internal (house) environments within Barrow-in-Furness was found to be derived from the primary input event of Chernobyl fallout. The specific activity of radiocaesium in the dust reservoirs studied, decreased exponentially, enabling environmental half-lives to be calculated (190-370 day). The broad similarity of these half-lives indicated that secondary contamination processes, such as atmospheric deposition of resuspended dust, cause all the internal and external reservoirs to be linked into a system encompassing much of Barrow-in-Furness. Mean residence times of external dust were derived from the calculated environmental half-lives and measurements of atmospheric deposition (150-250 day). These mean residence times are dependent on local processes and are thus site specific, whilst the environmental half-lives represent an integration of all the processes operating in Barrow-in-Furness.

Accidents↗

Effect of dry deposition, washout and resuspension on radionuclide ratios after the Chernobyl accident.

The temporal variations of radionuclide ratios in air and deposition samples collected simultaneously at Munich-Neuherberg (F.R.G.) after the Chernobyl accident have been studied. Until 8 May 1986, the radionuclides investigated were 99Mo, 103Ru, 106Ru, 110mAg, 125Sb, 129mTe, 132Te, 131I, 134Cs, 137Cs, 140Ba, 141Ce and 144Ce. After 8 May, 99Mo, 110mAg, 125Sb, and the Ce isotopes were below the detection limits. Considerable temporal variations of the above radionuclides, relative to 137Cs, were observed in air as well as in deposition. In air the temporal variations reflect the arrival of different parts of the reactor plume with different elemental composition. In deposition, the temporal patterns were quite different from those in air for a given radionuclide. This is explained by varying contributions of dry and wet deposition. Until 8 May, the washout ratios of the above radionuclides covered a range from 240 to 5600, with smaller variations for all radionuclides within one event (e.g. 460-910), and larger variations from one event to another (e.g. 460-3300 for 137Cs). The dry deposition velocity of 137Cs was found to be 0.27 cm s-1, similar to that of 110mAg, aerosol 131I and 140Ba (0.37, 0.13 and 0.15 cm s-1). Another group of radionuclides includes 103Ru, 106Ru, 125Sb, total 131I and 132Te with dry deposition velocities of 0.08, 0.10, 0.07, 0.03 and 0.08 cm s-1 and with temporal variations in deposition which are quite different from those of the first group. From 8 May to the end of June, the washout ratios increased to values between 1500 and 24,000, with the exception of iodine, which had considerably lower washout ratios of between 37 and 4400. These later effects are explained by resuspension and, in the case of iodine, by remobilization of gaseous species.

Accidents↗