Assessment of Agricultural Workers' Exposure Due to Crop Harvesting Operations Within the Areas Affected by Radioactive Contamination.

Implementation of field experiments took place in two sites located in the Bragin district of the Gomel region, Belarus, i.e. a field in the evacuation zone and a private plot of land in a residential area of thedistrict. The objective of the research was to study the levels of radioactive contamination of air due to the dust raised up during crop harvesting operations. Comparative dose assessment was done to assess external exposure and committed effective doses of internal exposure due to inhalation of (241)Am, (238,239+240)Pu, (137)Cs and (90)Sr by agricultural workers involved in dust-generating harvesting operations. According to the results, the dominant contributors (93-97%) to internal exposure of agricultural workers both on a private plot of land and in the area of evacuation, were the transuranic elements (241)Am and (238,239,240)Pu. In the context of the total doses received by the harvest-workers, the dominant contribution belonged to external exposure which was 2-3 orders of magnitude higher than the levels of internal exposure due to inhalation of radionuclides.

[The transfer of 90Sr and of 137Cs radionuclides in the chain of soil-fodder-animal products in the area contaminated as a consequence of the Chernobyl AES accident].

The database on 137Cs and or 90Sr transfer factors in the soil-fodder-animal products chain compiled in the framework of the project "Radioecological Consequences of the Chernobyl Accident" under the French-German Initiative was analyzed. The 137Cs transfer factors were determined into 10 fodder types for farm animals. The 137Cs and 90Sr transfer from daily diet to milk is practically independent from milk yield and season and is about 0.83% and 0.16%. 137Cs transfer factor into beef (adult animals) is about to 2.4% from the daily uptake with fodder per 1 kg meat.

[Evaluation of parameters of radionuclide transition from soil particles and plant components of the upper layer of turf to cow's milk under pasture conditions]. / Otsenka parametrov perekhoda radionuklidov iz pochvennykh chastits i rastitel'noi komponenty verkhnego sloia derniny v moloko krupnogo rogatogo skota v usloviiakh pastbishchnogo soderzhaniia.

An experiment was conducted on feeding lactating cows with soil and turf additives contaminated with both 137Cs and 90Sr of the Chernobyl origin. The radionuclides transfer coefficients (%) in the food chain were for soil additives: for 137Cs--0.02 +/- 0.006, for 90Sr--0.01 +/- 0.002; for turf additives: for 137Cs--0.02 +/- 0.005, for 90Sr--0.06 +/- 0.035. Regarding 90Sr, there is no significant tendency to higher transfer rate for the radionuclide from turf component compared to that for soil component. A contribution of soil component as well as turf component of soil was evaluated as an additional source of milk contamination while grazing cattle. It was concluded that the contribution is not pronounced at the remedial period after the accident (approximately 3% from total activity consumed with ration) and it can be rejected in cattle breeding practice. The results achieved can be used for prediction of radionuclides concentrations in milk produce in cattle breeding under industrial contamination of agricultural lands.

[Evaluation of hormonal status indicators and adenylate cyclase activity in animals in the follow-up of the Chernobyl AES accident]. / Otsenka pokazatelei gormonal'nogo statusa i aktivnosti adenilattsiklazy u zhivotnykh v otdalennye sroki posle avarii na Chernobyl'skoi AES.

Enhancing stimulation effect of prostaglandin E1 on adenylate cyclase, decrease in basal activity of adenylate cyclase in platelets and reducing thyroxine concentration in cow plasma 5 years after radioiodine damage to thyroid gland with doses higher than 200 Gy were detected, whereas only decrease in adenylate cyclase activity in platelets from animals irradiated with 40 Gy to thyroid gland was observed. No changes in platelet adenylate cyclase in cows exposed to less than 1 Gy to thyroid gland after 5 years of maintenance on the territory with 137Cs contamination density lower than 0.37 MBq/m2 were found.