野鸭湖湿地土壤中砷汞分布特征及潜在风险评价

Content and Distribution Characteristics of Arsenic and Mercury in Soil from Yeyahu Wetland

为了解野鸭湖湿地土壤砷汞元素分布规律、形态组成及元素累积影响因素,探讨土地利用对土壤砷汞时空变化的影响,在北京延庆县野鸭湖湿地公园及周围几个镇采集表层土壤,采用原子荧光光谱法对砷汞总量测定,并用五步连续萃取和原子荧光光谱法测定砷汞形态,同时利用相关分析研究As、Hg元素分布的影响因素。结果表明:As、Hg元素在野鸭湖湿地土壤中平均含量10.07、0.088 7mg/kg;均超出北京市土壤背景值,其中草地、耕地中少数采样点低于背景值。砷元素与钒、铁、锰显著正相关(r>0.4,p<0.01);汞与锰正相关,钒、铁、锰含量会在不同程度上影响As的分布;而锰是影响Hg分布的主要因素。As主要形态为残渣态,Hg主要形态为有机物结合态和残渣态。采用风险评价编码法对研究区域的砷汞元素进行潜在生态风险评价,2种元素生态风险均较低。

In order to understand the distribution,arsenic（As）,mercury（Hg） element speciation and the influence factors of element accumulation in Yeyahu wetland soil,meanwhile,discuss the influence of land utilization on temporal and spatial variation of As,Hg in topsoil,total content of As,Hg with atomic fluorescence spectroscopy was measured,and the morphological characteristics of As,Hg were analyzed with step five consecutive extraction method and atomic fluorescence spectroscopy,and the influence factors of As and Hg element distribution were analyzed with correlation analysis. Results show that average content of As and Hg are respectively 10.07 mg/kg and 0.088 7 mg/kg,both above the soil background values of Beijing,while a few sampling points in the grassland and cultivated land are lower than the background values. p H and As were negative correlated;As and Hg were both irrelevant with organic carbon and redox potential. The principal speciation of As is residual form,while organic bound and residual form is the main influencing factor of Hg. Relatively the two elements are stable and potentially less harmful to the environment.