Natural Radionuclides in Meadow and Pasture land in the Nordic countries

The amount of natural radionuclides in the environment differs between the Nordic countries as shown by previous investigations and also by this study. Agricultural areas of high natural background are predominantly found in Sweden, Southern Finland and Norway while low background areas are typical for Iceland and Denmark. Thus, this study offers possibilities for studying behaviour of natural radionuclides under different conditions such as the influence of different soil types as well as the husbandry. Furthermore the areas also enable studying environmental behaviour of radium and other natural radionuclides under seemingly steady state conditions. However, migration and accumulation of natural radionuclides in cultivated soil is complex involving various processes. Thus, a long term goal of this study was to identify the implications of some of these processes by determining the soil to plant transfer for pasture land under the different conditions that prevail in the Nordic countries. The potential health hazards due to chronic ingestion of low concentrations of naturally occurring radionuclides are fairly unknown but the results of this study may provide valuable background information for assessing these radiation risks. The aim of this project has been to gain knowledge on the status of natural radionuclides in meadow and pasture land and in grassland plants in different Nordic countries and on the transfer of these radionuclides from soil/water to man via the milk/food chain (soilmeadow/pasture grass –cow-milk). Limited data are available on the mobility and the transfer of naturally occurring radionuclides in the ecosystems of the agricultural land. In addition, information concerning the concentrations in meat and dairy products is of interest for assessing exposures of humans to natural radionuclides. Soil characteristics are known to have significant impact on the mobility and uptake of natural radionuclides. Therefore, the uptake in relation to different soil types such as sandy, organic and/or clay soil was investigated. The use of fertilizers at some of the investigated farms has been considered but no analysis was performed on the content of natural radionuclides in fertilisers.