杨俊诚　朱永懿　陈景坚　刘学莲

　　对北京、内蒙、宁夏、河北、广东和天津等地大型火力发电厂粉煤灰的采样分析表明：粉煤 灰中主要放射性成分为238U、232Th衰变系和40K，比活度 范围分别为93.2～283.8Bq/kg,80.3～238.8Bq/kg和115.6～447.4Bq/kg。试样模拟研 究表明，当粉煤灰施用量达675T/hm2时，土壤中天然放射性核素226Ra和 228Ra的比活度分别是对照的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高处空气吸收剂量及地面γ辐射所致人均年有效剂量当量随粉煤灰的施用量增加呈现 增加的趋势。土壤中228Ra的比活度与粉煤灰施用量的相关性可表示为y=22.04x +17.25,(r2=0.9909)；对于226Ra，y=21.38x+2.45,(r2=0.9966)。地 面1m高处空气吸收剂量率(D)与粉煤灰施用量的相关性可表示为：y=1.896x+3.875，(r2 =0.9891)。有效剂量当量(H)的变化与施用粉煤灰的量之间的相关性可表示为：y=23.245x +47.505，(r2=0.9891)。当粉煤灰施用量低于675T/hm2时，人均年有效剂量当量比对 照增加了15%，但仍低于全国人均有效剂量当量平均值；尽管如此，对粉煤灰的应用要加强 管理和监测。
　　关键词：粉煤灰　农业生态环境　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