宿州市表层土壤重金属元素环境地球化学基线研究

环境地球化学基线作为能够判别自然和人为环境影响的地球化学指标，不同地区基线值的确定具有重要的现实意义和参考价值。本研究以宿州市为例，通过野外采样和室内测试，对表层土壤中的Cu、Zn、Pb、As、Cr、V六种重金属元素进行总量分析，采用标准化方法和相对累积频率分析方法计算确定宿州市土壤环境地球化学基线，基于确定的地球化学基线值，运用地质累积指数法对宿州市表层土壤重金属污染进行环境地球化学评价。结果表明，研究区表层土壤中Cu、Zn、Pb、As、Cr、V的平均含量分别为18.29、52.61、20.84、10.29、69.83和82.27 mg/kg；确定的环境地球化学基线值分别为16.97、48.66、19.43、9.07、65.22和79.08 mg/kg，获得的基线值符合其定义和实际意义；地质累积指数计算分析结果显示，六种重金属元素大部分处于无污染级别，少量达到无污染到中度污染级别，六种重金属元素在表层土壤中的富集贫化不明显。

A Study on Environmental Geochemical Baselines of Heavy Metals in the Surficial Soil of Suzhou

The environmental geochemical baseline is an indicator for discriminating natural and anthropogenic environmental hazardous substances, and to establish environmental geochemical baselines in the particular area is of important practical significance and reference value. This study analyzed total contents of six heavy metals (Cu, Zn, Pb, As, Cr and V) in surface soils of Suzhou City, estimated their environmental geochemical baselines using the normalization approach and the relative cumulative frequency method, and evaluated their pollution status using the cumulative geochemical index and the obtained geochemical baselines. The results showed that the average contents of Cu, Zn, Pb, As, Cr and V in surface soils were 18.29, 52.61, 20.84, 10.29, 69.83 and 82.27 mg/kg, respectively, and that their environmental geochemical baselines were 16.97, 48.66, 19.43, 9.07, 65.22 and 79.08 mg/kg, respectively, which were in accordance with the definition and practical significance of these heavy metals. The results indicated that the six heavy metals in the most surface soils of Suzhou were at uncontaminated level, only few showed moderate contaminated level, and that no enrichment or depletion trend of six heavy metals was found in surface soils of Suzhou.