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.

芭茅山免炼造林及化学抚育技术

芭茅山造林及抚育一直以来是个大难题,目前大多仍然采用火炼造林、人工砍茅抚育,造林成本高、且成功率极低。芭茅山造林前,选用优质的"41%草甘膦异丙胺盐"可一次性彻底根除芭茅[Miscanthus floridulus(Lab.) Warb. ex Schum. et Laut.],割带造林后,选用"林清二号"(自行配制药剂)化学除茅,效果好。