楊俊誠　朱永懿　陳景堅　劉學蓮

　　對北京、內蒙、寧夏、河北、廣東和天津等地大型火力發電廠粉煤灰的采樣分析表明：粉煤 灰中主要放射性成分為238U、232Th衰變系和40K，比活度 范圍分別為93.2～283.8Bq/kg,80.3～238.8Bq/kg和115.6～447.4Bq/kg。試樣模擬研 究表明，當粉煤灰施用量達675T/hm2時，土壤中天然放射性核素226Ra和 228Ra的比活度分別是對照的3.56倍和2.60倍。土壤中天然放射性核素的比活度和 地面1m高處空氣吸收劑量及地面γ輻射所致人均年有效劑量當量隨粉煤灰的施用量增加呈現 增加的趨勢。土壤中228Ra的比活度與粉煤灰施用量的相關性可表示為y=22.04x +17.25,(r2=0.9909)；對于226Ra，y=21.38x+2.45,(r2=0.9966)。地 面1m高處空氣吸收劑量率(D)與粉煤灰施用量的相關性可表示為：y=1.896x+3.875，(r2 =0.9891)。有效劑量當量(H)的變化與施用粉煤灰的量之間的相關性可表示為：y=23.245x +47.505，(r2=0.9891)。當粉煤灰施用量低于675T/hm2時，人均年有效劑量當量比對 照增加了15%，但仍低于全國人均有效劑量當量平均值；盡管如此，對粉煤灰的應用要加強 管理和監測。
　　關鍵詞：粉煤灰　農業生態環境　天然放射性

AGRICULTURAL APPLICATION OF COAL ASH AND ITS RADIOACTIVE
CONTAMINATION TO ENVIRONMENT

Yang Juncheng Zhu Yongyi Chen Jingjian Liu Xuelian
(Institute for Application of Atomic Energy,CAAS,Beijing 100094)

　　ABSTRACT: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 radioactives ubstances are 238U,232Th,their daughter nuclides and 40K.The range of specific radioactivity for 238U is 93.2～283.8B q/kg,for 232Th, 80.3～238.8Bq/kg and for 40K, 115.6～447. 4Bq/kg.When amount of the coal ash applied is up to 675t/hm2 the specific radi oactivity of 226Ra and 228Ra are 3.56 and 2.60 times higher than those of control respectiviely.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=22.04x+17.25(r2=0.9909) and for 226Ra, y=21.38x+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=1.896x+3.875(r2=0.9 891) and for H, y=23.245x+47.505(r2=0.9891).
　　Key words:Coal ash,agricultural eco-environment,natural radioactivity