(1. 中南大学 冶金与环境学院，长沙 410083；
2. 核工业北京地质研究院，北京 100029；
3. 徐州市环境保护科学研究所，徐州 221006)
摘 要: 为了查明洞庭湖湿地周围表层土壤重金属污染及其对人体健康的风险，选择2016~2018年洞庭湖区域周围10个土壤采样点，共采集了表层土壤(0~30 m)样品100份，分析了其中的重金属含量、分布，并采用地累积指数法(Igeo)、内梅罗指数法(NI)和土壤健康风险评价法等方法进行了风险评价。结果表明：土壤样品中Pb、Cd、Hg、As和Cu 5种重金属元素的平均浓度分别为53.33、1.62、0.27、26.8和37.72 mg/kg，高于研究区域土壤环境背景值。其中Cd、As的平均浓度，西洞庭湖、南洞庭湖和东洞庭湖Cd的浓度和南洞庭湖As的浓度均高于《土壤环境质量标准》(GB 15618—2018)中农用地土壤污染风险筛选值的标准。Cd、Hg、As和Cu的最大污染值在南洞庭湖，Pb的最大污染值在东洞庭湖。地累积指数法(Igeo)研究表明，三年时间里，Cd处于重度污染水平，Pb、Hg、As处于无污染到中度污染水平。内梅罗指数法(NI)研究表明，三年时间里，西洞庭湖、南洞庭湖和东洞庭湖都处于轻度污染水平。运用土壤健康风险评价体系中的无意吸食、皮肤接触、呼吸接触3种暴露因素对人体健康风险的评估表明：每百万人口中，平均有13个成年人和8个儿童具有癌症风险。研究结果为洞庭湖湿地土壤污染的来源和特征提供参考和建议。
关键字: 洞庭湖；土壤；重金属；污染；人体健康风险评价
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Beijing Research Institute of Uranium Geology, Beijing 100029, China;
3. Xuzhou Institute of Environmental Protection Science, Xuzhou 221006, China）
Abstract:In order to find out the pollution of heavy metals in surface soil around Dongting Lake wetland and its risk to human health, 10 soil sampling sites around Dongting Lake area were selected in this study from 2016 to 2018. 100 surface soil samples (0-30 m) were collected. The content and distribution of heavy metals were analyzed, and the methods of geo-accumulation index (Igeo), nemerow index (NI) and soil health risk assessment were used for risk assessment. The results show that the average concentrations of Pb, Cd, Hg, As and Cu in soil samples are 53.33, 1.62, 0.27, 26.8 and 37.72 mg/kg, respectively, which are higher than the background values of soil environment in the study area. Among them, the average concentrations of Cd and As, the concentrations of Cd in West Dongting Lake, South Dongting Lake and East Dongting Lake and the concentrations of As in South Dongting Lake are all higher than the criteria for screening the risk of agricultural land soil pollution in “Soil Environmental Quality Standard” (GB 15618—2018). The maximum pollution values of Cd, Hg, As and Cu are in South Dongting Lake, while the maximum pollution values of Pb are in East Dongting Lake. The study of geo-accumulation index (Igeo) show that Cd is at the level of serious pollution, and Pb, Hg and As are at the level of non-pollution to moderate pollution in three years. The nemerow index (NI) study shows that, in three years, West Dongting Lake, South Dongting Lake and East Dongting Lake are at slight pollution level. The assessment of human health risks using the three exposure factors of unintentional smoking, skin contact and breath contact in the soil health risk assessment system shows that the average of 13 adults and 8 children per million population are at risk of cancer. The results provide reference and suggestions for the sources and characteristics of soil pollution in Dongting Lake wetland.
Key words: Dongting Lake; soil; heavy metal; pollution; human health risk assessment
