青海省民和县-海石湾土壤Hg异常调查及其生态效应

Hg Element Abnormality in Soils of Minhe and Haishiwan City and Its Ecological Impacts

通过对民和县-海石湾城区及其周边地区表层土壤Hg元素异常空间分布特征的分析,查明了大气降尘是当地Hg异常的最主要来源,此外生活、工业固废污染也是可能的原因;在垂向分布上,自上而下Hg元素大体呈上升趋势,显示表面Hg元素富集。对土壤中Hg形态进行特征分析,探讨了Hg的各形态与含量之间的相关性,结果显示:残渣态>强有机态>腐植酸态>铁锰氧化态>水溶态>碳酸盐态>离子交换态。异常区土壤Hg的累积并未造成小麦及玉米的重金属超标,未影响到其食用安全性,但是潜在威胁性存在。

It is proved that atmospheric Hg are the main sources of Hg pollution in the surface soils according to the study on spatial distribution characteristics of heavy metal abnormality in and around Minhe and Haishiwan City based on the data from regional eco - geochemical survey. It is found that heavy metals are accumulated in top sOil layer and the Hg increased when comes to the top soil layer. According to the characteristic analysis of morphology of Hg in soil, discussions are made on the correlation between morphology of Hg and content of Hg. The result of soils Hg species analysis indicated the following order： leavings form 〉 bio - refractory organic form 〉 combined humic acid form 〉 Fe/Me oxide form 〉 soluble form 〉 carbonate form 〉 exchangeable form. Heavy metal contents in the wheat and corn produced in heavy metal anomaly areas have not exceed National Food Safety Standards, but the potential danger still exists.