Radio-ecological problems of the South Kazakhstan in connection with uranium deposits of Shu-Sarysuy and Syrdarya provinces

The South Kazakhstan is a region of the Republic with most alarming epidemiological situation. Almost all medical indicators of health condition of inhabitants including children are much lower than the average statistical one for the Republic in whole. One of the main reasons for high morbidity level of the South Kazakhstan inhabitants, undoubtedly, is a critical point of ecological and radio-ecological situation in this region. There are some mechanisms that formed this situation. One of them is the intensive agricultural activity with use of chemical (phosphor, potassium, nitric) fertilizers. The next mechanism is the pollution of the environment and waters with industrial and domestic wastes and effluents of large cities. The most important and least studied feature for this region is presence of considerable reserves of natural uranium (20-30 % of world reserves) and long-lived, intensive industrial activity on its mining and processing. According to geological character the deposits of Shu-Sarysuy and Syrdarya uranium-ore provinces, generally, belong to deposits of bedded-infiltration type in low-lithified sediment rocks. The ore substances of these deposits are allocated in regional fronts of the zones of bedded oxidation on the horizon of chalk and Palaeocene. Along these fronts a vast aureole of bedded waters were formed with anomalous concentrations of radionuclides, especially, of 226Ra (up to 50 Bq/l) and uranium (up to 150 μg/1). Besides, a vast outlet of carbonaceous-siliceous shale characterized by 'hurricane' contents of rare and dispersed elements such as V, Cr, Co, As, Se, Hg, Th, and U is observed at the sides of the mountain range Karatau. Mining process was prevented by great bore-hole exploring works over several ten years. The provinces are located in the range of artesian basins. In this connection, water well-spring occurred at many bore-holes (as a result of crippling of locking device). This mass uncontrolled process leads to intensive territory contamination (and, as a consequence, main water arteries) with both toxic elements and radionuclides. Thus, an eventual infringement dose burdening to inhabitants of this region is stipulated with a high dose of external irradiation, livestock pasturing and other agricultural works at contaminated territories, unruled use of local materials for construction and water use for drink and domestic purposes from contaminated waters. The Report presents the main investigation results on radiation situation and contamination rate with toxic elements in regions of well-springing boreholes and at places of uranium extraction by the method of underground leaching (Shyili deposit) obtained during last years