Agricultural application of coal ash and its radioactive contamination to environment

Sampling from the electric power plants of Beijing, Inner Mongolia, Ningxia, Hebei, Guangdong and Tianjin, coal ash samples were determined respectively by HPGe γ spectrometer analyzer. The results show that the main composition of radioactive substances are 23'8U, 232Th, their daughter nuclides and 40K. The range of specific radioactivity for 238U is 93.2-283.8 Bq/kg, for 232Th, 80.3-238.8 Bq/kg and for 40K, 115.6-447.4 Bq/kg. When amount of the coal ash applied is up to 675 t/hm2 the specific radioactivity of 226Ra and 228Ra are 3.56 and 2.60 times higher than those of control respectively. The increase of natural specific activity in soil varies with the amount of the coal ash applied, the expression of coefficient curve for 228Ra is y = 22.04 x +17.25 (r2 0.9909) and for 226Ra, y = 21.38 x + 2.45 (r2 = 0.9966). The same trend is shown with absorbed dose in air (D) and the annual effective dose (H), for D, y = 1.896 x + 3.875 (r2 = 0.9891) and for H, y = 23.245 x + 47.505 (r2 0.9891)