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Preliminary data - radioactive contamination 



[illegible], Novosibirsk, Tomsk, Magadan, Krasnoyarsk 



Medical Problems from Exposure to Radiation 



In the Altay kray radioactive contamination is a great concern, due to its 

 geographical location in the south of Western Siberia in the immediate vicinity of China 

 and Kazakhstan. Among the main sources of radioactive contamination of the 

 enviroimient in this Region, the following have been identified: a series of powerful 

 nuclear explosions conducted on the Semipalatinsk test site and in China, the accident at 

 the Chernobyl nuclear power plant, nuclear tests on Novaya Zemlya, combustion 

 products of organic fuel in boilers, heat and power plants, dusting from ash dumps, and 

 also sources of radioactive contamination of natural origin. 



Radioactive contamination of soil in the territory of the Altay kray is determined 

 mainly by the accimiulation in the sofl aver many years of fallout from long-lived 

 strontium-90 and cesium-137 that had been emitted into the atmosphere during nuclear 

 weapons tests. In addition, mineral fertilizers applied directly into the soil are a 

 significant source of its radioactive contamination. Contamination of surface waters is 

 caused by the wash-off of strontium-90 from the soil surface by atmospheric 

 precipitation. 



In Novosibirsk oblast, radiometric sampling of atmospheric fallout (according to 

 the monthly data from the Center for Monitoring Enviroimiental Contamination) 

 indicated that during 1990-1991 the fallout density did not exceed the established control 

 value of 1*10 Bq/m^ per day in terms of total beta-activity, and on average was 0.7 Bq/m^ 

 throughout Novosibirsk oblast. At the permanent sites for recording radioactive 

 contamination, the mean values of fallout density are as follows: 0.8±0J Bq/m^ in the 

 cities of Bolotnoye and Karasuk, 1.0±0.4 Bq/m^ in the city of Barabinsk, 1.5±0.7 Bq/m^ 

 in the city of Novosibirsk, and 1.4±0.7 Bq/m^ in the town of Ogurtsovo. The maximum 

 radioactive fallout was 6.3 Bq/m^ in Barabinsk, 10.0 Bq/m^ in Novosibirsk, and 18.5 

 Bq/m^ in Ogurtsovo. 



The radioactivity of the surface atmospheric layer was caused by fallout from the 

 stratosphere of products of the decay of radioactive substances during nuclear tests 

 conducted in previous years. Basically the radioactive contamination is determined by 

 the presence of substances such as cesium-137; in a number of cases contamination by 

 thorium-232 from the soil was noted. 



The soil dose rate is, on average, 20-50 /xr/hr, yet in some cases the maximum 

 dose goes up to 275 /ir/hr (in the exclusion zone of the tailing dump of the Production 

 Association Khimkontsentrat in the city of Novosibirsk, which results from the 

 production activities of this enterprise). 



