Bioaccumulation of 226Ra in the plants growing near uranium facilities

Radiopollution of soils in the close neighbourhood of a uranium mine and a uranium mill was characterized using measurement of specific 226Ra activity by gamma spectrometry. It was found that it ranged from values lower than the admissible limit of 0.2 Bq.g 1 of soil (averaged over the first 15 cm below the ground surface) to values more than one hundred times higher. Bioaccumulation of 226Ra from the measured soils in plant species which were naturally growing on the analysed sites was analysed. The specific 226Ra activity of aboveground dry plant parts ranged within two orders of magnitude. Currently occurring and simply collected Mentha piperita was found to be useful for biomonitoring of soils.