某钽铌厂及周边土壤放射性水平调查与健康风险评估

Investigation and Health Risk Assessment of Soil Radioactivity Level in Tantalum-niobium Plant and Its Surroundings

为查清厂区及周围土壤环境中放射性污染程度,对该厂周边表层土壤(0~0.3m),以及重污染点0~0.3、0.3~0.6、0.6~0.9m三组土壤中放射性核素^(238)U、^(232)Th、^(226)Ra、^(40)K比活度进行现场勘察和统计分析,查明其在土壤中的分布特征。描述性统计结果表明,在R1点^(238)U比活度最高,为5860Bq/kg,而其余三种核素(^(232)Th、^(226)Ra、^(40)K)含量均是R2处数值高,分别为930、1420、367Bq/kg。在统计结果基础上,采用潜在生态风险指数法与暴露评估模型评价其污染程度和对人体健康危害程度,结果表明,R1、R2两处点位属于强生态风险、R3为中等潜在生态危害,其余点位为轻微生态危害;儿童与成人经呼吸渠道对人体无非致癌风险,而经口摄入途径,儿童均有非致癌高风险,成人在S1点位处为可能存在非致癌风险,其余均有非致癌高风险。

In order to find out degree of radioactive pollution in soil environment of plant and its surroundings,field investigation and statistical analysis were conducted on activity concentrations of radionuclides of ^(238)U,^(232)Th,^(226)Ra,and ^(40)K in surface soil around the plant(0-0.3m)and in soil of 0-0.3,0.3-0.6and 0.6-0.9 mof heavy contamination points to find out their distribution characteristics in soil.The descriptive statistical results show that ^(238)U has the highest activity concentration of 5860Bq/kg point in R1,while the other three nuclides(^(232)Th,^(226)Ra,^(40)K)have the highest value of 930,1420,367Bq/kg in point R2.On the basis of statistical results,potential ecological risk index method and exposure assessment model were used to evaluate the pollution degree and harm degree to human health.The results show that point R1and point R2 were strong ecological risk,point R3was moderate potential ecological risk,and the other points were slight ecological hazard.There is no carcinogenic risk for children and adults through respiratory channels,while there is a non-carcinogenic risk for children through oral ingestion.There is possible non-carcinogenic risk for adults at point S1and non-carcinogenic risk for others.