Transfer Factors of 226Ra and 232 Th in Chain Soil-Vegetation

Preliminary results of ongoing study of natural radioactivity around the coal power plants in Bosnia and Herzegovina are presented in the paper. Dried samples of soil and mineralised samples of vegetation were used for 226Ra and 232Th transfer assessment in soil-vegetation chain. Sampling was performed at different distances from the active or closed landfills in Bosnia and Herzegovina. Measurements were performed by gamma spectrometry method with use of the high resolution HPGe detector and additional equipment. Range of 226Ra transfer factors was 0.005-0.110 with mean value 0.031, while the same for 232Th was 0.006-0.120 (with mean value 0.026). Despite the generally high variability of the results, obtained values of transfer factors showed good agreement with literature. Variability of the results was consequence of the different deposition levels of the resuspended coal ash at the surfaces of the plant and soil, caused by the several factors (distance, dominant wind direction, agricultural activities etc.). Further investigation should be aimed to differentiation and quantification of transfer among the different pathways (root uptake and foliar uptake) in order of assessment of annual ingestion dose for population and domestic animals. (author).