Agricultural production as a source of irradiation of populations in radiation accidents

Radioactive contamination of the agricultural production sphere in case of a radiation accident with radionuclide release is one of the most important sources of additional irradiation for population. As a result, realisation of the measures for mitigating the consequences of the accident in agro-industrial complex assumes the leading role in total system of measures providing radiation safety. The possibility to obtain agricultural production meeting the radiological standards is one of the main indications of effectiveness of liquidation of the accident consequences. First, obtaining of agricultural production meeting the radiological standards provides decreasing of the total radiation dose. The evidence is obtained in the 8-year experience of liquidation of the Chernobyl NPP accident that the 70% decrease of the internal dose for population became possible through a complex of protection measures in agriculture (during the first year after the accident, the contribution of internal dose into the total one amounted to 45%, and that of external irradiation - 52%; for the 70-year period these values are 39% and 60%, respectively). Second, the possibility to obtain 'pure' agricultural production is one of the most important factors of psychological stability for population. Third, obtaining of consumable (as to radionuclide content) agricultural production in private small holdings is one of the guarantees of stability of demographic sector in the accident-affected zone. From the point of view of organization of agricultural production in liquidation of the consequences of accidents with radioactive releases into environment, some periods can be distinguished: (i) the first (early) period takes 10-12 days after the accident. The main measures in the field of agricultural production are in operative assessment of the radiological situation, organization of radiation survey, express classification of agricultural products ready to consumption. If radionuclide content in food products and feeds exceeds the DILs, their consumption is prohibited. The prophylactic measures to prevent adverse iodine effects are rendered a special place. If necessary, agricultural animals are relocated; (ii) the second period lasts 2-3 months after the accident. At that time radiological maps of contaminated lands are made, the system of radiation control of agricultural lands and agro-industrial production is perfected, the program of technological processing of contaminated agricultural products is implemented which guarantees obtaining of non-contaminated products; (iii) the third period is completed after the first 1.5 post-accident years. Agroamelioration measures are carried out at that time, the main scope of measures for detailed radiological survey of contaminated lands is realised; gradually the concept of production classification is replaced by the zonal production organization guaranteeing the Derived Intervention Levels established for the given period are not exceeded. The scientifically substantiated program of agricultural production management on contaminated lands for maximum possible obtaining of pure production and rational use of agricultural lands is formed; (iv) the fourth period starts in 1.5-2 years after the accident. In case that the deposited mixture of radioactive substances contains the log-lived radionuclides (90Sr, 137Cs, 239Pu, etc.), the program of obtaining production meeting the radiological standards is realised as a constant long-term complex, in parallel with realisation of long-term system of agro-industrial measures, reorientation of agro-industrial production system and processing of contaminated products. (author)