摘要
为掌握某遗留场地放射性污染状况和为场地管理及利用提供依据,利用γ剂量率仪对场地进行1 m网格现场巡测,对热点区土壤进行布点采样,测定^(226)Ra、^(238)U、^(232)Th和^(40)K的活度浓度,同时对厂区井水、厂区排水口下游约50 m池塘水及居民家饮用井水进行采样,测定总α放射性和总β放射性。结果表明,该场地主要污染介质为土壤,主要污染核素为^(226)Ra,土壤样品中^(226)Ra的最大活度浓度为5.306×10^(4)Bq/kg。利用美国EPA的健康风险评估模型开展风险计算,结果表明,该场地最大风险来源于^(226)Ra,风险值为3.71×10^(-4),是可接受风险值(10^(-4))的3.71倍;^(40)K的最大风险值为6.23×10^(-5),在可接受范围内;^(232)Th和^(238)U的最大风险均低于10^(-6),可忽略。从^(226)Ra的风险暴露途径来看,摄入风险占总风险的70.89%,为主要风险暴露途径,外照射风险占总风险的29.11%,而吸入风险占比仅0.001%。
The paper is inclined to make a survey of the radioactive pollution or contamination by a gamma dose rate meter in a forsaken site and provide basis for the site management and utilization with the grid survey being divided into 1 m×1 m grids.At the same time,the boundary area of the hot spots can be identified preliminarily with the enmeshing grids in the hot spots.Besides,we have also used the plum blossom sampling method to collect the surface soil samples,with the deep column sampling modes chosen to examine the highestγdose rate on-site in each hot spot area.And,later,we have also analyzed the activity concentration rates of ^(226)Ra,^(238)U,^(232)Th and ^(40)K in the soil samples by HPGe gamma spectrometry.Besides,we have also made sampling on the groundwater in the abandoned site,drinking water samples from the nearby residents and pond water at the downstream ponds of the plant drainage located at about 50 meters north to the plant.And,furthermore,we have also done an analysis of the gross alpha activity and the gross beta activity of the water samples with the thick source method and the evaporation method respectively.Thus,as a result,the major contaminated radionuclide in the site has been found being ^(226)Ra,whereas the background and greatest activity concentration serve as 65.43 Bq/kg and 5.306×10^(4)Bq/kg respectively.And,when we conducted the health risk assessment by using the health risk assessment model for radioactive contaminated site of USEPA,we have got to know that the greatest contamination risk of the site comes from226Ra,while the maximum carcinogenic risk is3.71×10^(-4),which is equal to 3.71 times of the acceptable risk(10^(-4)).Besides,the maximum risk of ^(40)K is 6.23×10^(-5),though it can be still tolerable.Apart from it,the maximum risk of ^(232)Th and ^(238)U can be regarded as being lower than 10^(-6),which can be taken as negligible.Hence,according to the risk exposure pathway of ^(226)Ra,ingestion is the main exposure pathway,which may contribute to 70.89%of the total r
作者
李战国
朱勇兵
李军
王善强
赵红杰
LI Zhan-guo;ZHU Yong-bing;LI Jun;WANG Shan-qiang;ZHAO Hong-jie(State Key Laboratory of Nuclear Biological and Chemical Protection for Civilian,Beijing 102205,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2020年第6期2408-2415,共8页
Journal of Safety and Environment
基金
国家重点研发计划项目(2018YFC1801105)
国民核生化灾害防护国家重点实验室科研基金项目(SKLNBC2019-01)。
