Assessment of the contribution of natural, technogenic and radionuclide factors to the spread of cattle leukemia in the Chelyabinsk region

The Chelyabinsk region is located in various geographical countries and zones: the Ural-mountainous country and the West Siberian low-lying country, which, in turn, occupy the mountain-forest, forest-steppe and steppe zones. The tense ecological situation of the region is associated with radioactive and intense technogenic pollution of the territory. Excess of the natural radiation background in the territory occurred after a major radiation accident in Kyshtym, which formed the East Ural Radioactive Trace (EURT), which was formed mainly in the Ural-mountain physiographic region in the north of the region. Industrial pollution caused by industrial emissionslarge enterprises and soil degradation as a result of mining operations.  In general, the EURT covered 384 settlements ( 29.7%) in the Chelyabinsk region .

The aim of this work is to assess the contribution of natural, radionuclide, and technogenic factors to the level and risk of the spread of cattle leukemia in the Chelyabinsk region , one of the most disadvantaged Russian regions for this disease. cattle. Objects of research: cattle of black-motley breed, calves of different ages, fattening young animals, lactating cows. The monitoring duration was 1993-2018 years. On the EURT and in the zone of influence of the Techa and Bagaryak rivers, 5 regions of the Chelyabinsk region were investigated: Argayashsky, Kaslinsky, Krasnoarmeysky, Kunashaksky and Sosnovsky. The control for them was another 23 districts that were not contaminated with radioactive fallout after the accident at the Mayak Production Association. 

A statistically significant association was established between the degree of radioactive contamination of the territory of the Chelyabinsk region and the intensity of the epizootic situation in cattle leukemia. The degree of influence of factors of the natural and socio-economic background on the frequency of occurrence and the extent of damage to animals from the disease is calculated. For the first time, simulation models are presented reflecting the relationship between the density of radionuclide contamination and the frequency of registration of dysfunctional sites, the number of infected VLCKR, patients rejected due to leukemia of animals. Cartograms of the spatial distribution of indicators of the relative registration frequency (stationarity index) and leukemia livestock infection rate were compiled. A comparative analysis of the cartograms of the epizootic situation with the maps of technogenic pollution, the state of the natural and socio-economic background established the confinement of the highest values ​​of the situation tension to regions of high technogenic pollution, including radioactive (urbanized areas), with intensive dairy farming of forest and forest-steppe landscape zones. Using elements of logical modeling in the form of a logical function of nonlinear logical multiplication of the probability model of the occurrence of the disease and the model of the possible infection of the livestock with leukemia, 5 zones of epizootological risk were identified in the Chelyabinsk region for the period until 2020 . The areas of highest epizootological risk are the northern most urbanized areas of the region.