Natural Radioactivity in Miscanthus floridulu Plant from the Uranium Tailing Pile at Guangdong, South China

Large amounts of uranium waste rocks and tailings resulting from the exploitation and treatment of uranium ore at the Northern Guangdong mine (South China) have been accumulated in dams (tailing ponds). To reduce the dispersion of natural radionuclides into the environment, some dams were revegetated with arbor, bush and sward. Besides these plants, Miscanthus floridulu is the dominant plant growing in some of the dams. The uptake and distribution of naturally occurring uranium (²³⁸U), thorium (²³²Th), radium (²²⁶Ra) and potassium (⁴⁰K) by Miscanthus floridulu plant from different sample sites of uranium mine were studied under native conditions. The bioconcentration factors (BCFs) of soil to Miscanthus floridulu above-ground and root were calculated and observed to be in the range of 0.14 to 7.74 and 2.71 to 17.83 for ²³⁸U, 0 to 3.02 and 0 to 3.29 for ²³²Th, 0.15 to 79.76 and 1.01 to 50.22 for ²²⁶Ra and 3.00 to 8.41 and 2.69 to 11.22 for ⁴⁰K, respectively. The transfer factors (TFs) of Miscanthus floridulu root to aboveground were also calculated and observed to be in the range of 0.01 to 0.73 for ²³⁸U, 0 to 0.99 for ²³²Th, 0.08 to 1.50 for ²²⁶Ra and 0.57 to 1.94 for ⁴⁰K, respectively. The results showed that, Miscanthus floridulu is ²³⁸U and ²²⁶Ra-accumulating plant with significant absorption and accumulation characteristics.