Soil-to-plant transfer factors for natural radionuclides in grass in the vicinity of a former uranium mine

Abstract The activity concentrations of 238 U, 230 Th, 226 Ra and 210 Pb were determined in soil and grass samples collected from sites at the uranium mill tailings waste pile, which lies near the former uranium mine at Žirovski vrh in Slovenia. Soil-to-plant transfer factors were determined and the potential use of grass as a monitor of radionuclide migration from the waste pile was evaluated. It was found that grass was not suitable for monitoring 230 Th and 210 Pb migration (no linear correlation between soil and grass activity concentrations) but has potential in predicting 238 U and 226 Ra migration (linear correlation between soil and grass activity concentrations). Soil-to-plant transfer factors for grass were in the range from 0.0014 to 0.015 kg/kg DM for 238 U, 0.0039 to 0.012 kg/kg DM for 230 Th, 0.035 to 0.46 kg/kg DM for 226 Ra and 0.098 to 1.5 kg/kg DM for 210 Pb.