Soil to leafy vegetable transfer factors for 226Ra, 210Pb, 40K and 137Cs in Kaiga region

The radionuclides present in the environment may enter plants through (i) uptake from soil through root, and (ii) direct absorption through aerial parts of the plants. The former depends on the concentration of radionuclide in soil as reservoir and the latter on the rate of radionuclide deposition from the atmosphere. While some radionuclides are taken up as homologous of essential elements, other radionuclides are taken up irrespective of their biological necessity. Though, extensive studies on distribution and transfer mechanism of different radionuclides in different environmental compartments and the resulting radiation dose have been carried out, these studies are no means complete. It is recognised that theoretical models that are used to predict the environmental transport and ensuing doses resulting from the release of radioactivity involve uncertainties due to the lack of site-specific information. Therefore, estimation of site-specific transfer factors for radionuclides in various environmental pathways around a nuclear power plant is essential to evaluate radiological hazard to the population. We have carried out a detailed site specific study on soil to vegetable (leafy vegetables - Spinach, Cassia, and Radish) transfer factors for radionuclides in Kaiga region, where a nuclear power station is in operation since the year 1999. The study had two objectives: (i) to estimate the soil to vegetable transfer factors for natural (226Ra, 228Ra, 40K and 210Pb) and artificial (137Cs) radionuclides under natural field conditions, and (ii) to compare the transfer factors obtained for the vegetables grown by the local farmer with those obtained for vegetables grown very close to the nuclear power plant using the water from the coolant water discharge canal of the nuclear power plant