沈阳市老城区表层土壤重金属分布特征及风险评价

以沈阳市老城区表层土壤为研究对象，共设置了10个采样点采集表层土壤样品。通过火焰原子吸收分光光度法和原子荧光法测定土壤样品中Zn、Cr、Ni、Pb、Cu、As、Cd元素的含量，分析了其分布特征，并使用单因子污染指数法、潜在生态危害和人体暴露风险评价模型评价了环境风险及人体暴露风险。结果表明:除As外，其他6种重金属平均含量均高于沈阳市土壤背景值，其中，金属Zn、Cd和Pb的平均含量分别是土壤背景值的3.45，3.03，2.67倍；单因子污染指数法结果表明:除As处于清洁状态外，其余元素均有不同程度的污染，尤其是Zn和Cd已达到重度污染；潜在生态风险指数评价结果表明:Cd的生态风险程度达到较强危害，其余都属于轻度潜在生态风险，城市总潜在生态风险指数RI=44.28，处于潜在中等生态危害；人体暴露风险评价结果表明:儿童的日平均暴露量和非致癌风险均高于成人，但总非致癌风险未超过1，致癌风险值也较低。

RISK ASSESSMENT AND CHARACTERISTICS OF HEAVY METALS IN SURFACE SOIL OF OLD TOWN OF SHENYANG

In order to study the surface soil of old town of Shenyang City,10 soil samples were collected in five major urban areas.The content of Zn, Cr, Ni, Pb, Cu, As and Cd in soil samples was determined by flame atomic absorption spectrometry and atomic fluorescence spectrometry,and their distribution characteristics were analyzed.The single factor pollution index method, potential ecological risk and human exposure risk assessment were used to analyze environmental risk and human exposure risk.The results showed that the average content of six heavy metals except As in old town was higher than that of Shenyang background values, among which the average content of Zn, Cd and Pb reached 3.45, 3.03 and 2.67 times of the background values; The single factor pollution index method result showed that As was in a clean state, but all the other elements had different levels of pollution, especially Zn and Cd reached heavy pollution level.The potential ecological risk result showed that Cd reached strong harm and other elements belong to slight level, and the total potential ecological risk index of the city, RI=44.28, belong to medium level of risk.Human exposure risk assessment result showed that children’s daily average exposure and non-carcinogenic risk were higher than that of adults, but the total non-carcinogenic risk of the studied heavy metals was less than 1, and the risk of carcinogenic heavy metals was also low.