ANALYSIS OF URANIUM DISTRIBUTION IN AEROSOL DEPOSITS ON THE TERRITORY OF NOVOSIBIRSK

Abstract

Relevance. Biogeochemical indication (by plants) of the state of the environment is widely used in geoecological studies of territories. It allows identifying the sources of anthropogenic impact, the boundaries of the zone of non-accidental emissions of large industrial enterprises, including nuclear fuel cycle facilities. A complex of laboratory and mathematical methods was used to estimate U aerosol deposition on the urbanized territory as a result of the regular activity of the nuclear fuel cycle enterprise. The aim of the research is to establish the nature of distribution, forms of location and pathways of migration of uranium in the zone of influence of the nuclear fuel cycle enterprise (on the example of Novosibirsk) according to the sampling of poplar leaves. Methods. Biogeochemical survey of the territory was carried out. The elemental composition of poplar leaf ash was studied by instrumental neutron activation analysis. The elemental composition of particles on the leaf surface was studied using a scanning electron microscope with X-ray spectral analysis. U migration pathway was determined by autoradiography. Numerical analysis of the spatial distribution of uranium concentration was performed based on the mass balance ratios of a light impurity in the surface layer of the atmosphere. The results obtained were processed using descriptive statistics. Results. The data on the distribution patterns and migration pathways of U in the zone of influence of nuclear fuel cycle facilities in the territory of Novosibirsk were obtained. Highly contrasting biogeochemical halos of U were identified in the northeastern part of the city. Quantitative changes of U concentrations in the southern directions of atmospheric U removal from the solid radioactive waste tailing pond were determined. The character of distribution of U concentrations over the height of tree crowns in the vicinity of the nuclear fuel cycle enterprise was studied – on the windward side from its industrial site the U concentration in samples of poplar leaves is 2–3 times higher than on the leeward side. Mineral phases of U oxide with sizes from 0,5 to 6 microns were fixed on the leaves surface. The windward pathway of U entry was established.

Keywords

• uranium
• aerosols
• wind transport
• poplar leaves
• novosibirsk
• neutron activation analysis
• sem-eds
• autoradiography
• mathematic modeling