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.