贵阳表层土壤中铬的环境地球化学基线研究

以土壤环境地球化学研究为主线,以贵州省贵阳市8046km2为研究区域,将土壤重金属污染元素铬的空间分布规律与环境地球化学机理研究相结合,建立了研究区域内表层土壤中铬元素的地球化学基线,并选用合适的判别指标判识自然作用过程与人类活动过程对土壤环境的影响.研究结果表明,贵阳市表层土壤中铬的基线值为44.0 mg·kg-1.地质累积指数分析结果显示,贵阳市46%的表层土壤未受铬的污染,47%的表层土壤在无污染到中度污染之间,6.8%的表层土壤为中度污染,只有0.2%的表层土壤介于中度污染到强污染之间.污染程度指数分析结果则显示,贵阳市69.2%的表层土壤未受到铬的污染,铬的污染程度最大为2.01,98.4%的表层土壤污染程度小于1,总污染程度小于0,即总体未受到污染.

Geogenic distribution and baseline concentrations of Cr in surficial soil of Guiyang

Environmental geochemical characteristics of the heavy metal pollutant Cr in the surficial soil of Guiyang, the capital city of Guizhou Province are described. The baseline concentration of Cr in soil and geochemical norms were determined to distinguish natural from artificial influences on the environment. Using statistical analysis, we have established the baseline of Cr in Guiyang to be 44.0 mg·kg-1. Geoaccumulation index calculations indicated that non-contaminated surficial soil accounts for 46 %, 47% was between non-polluted and mid-level polluted, 6.8% was mid-level polluted, and only 0.2% was between mid-level polluted and severely polluted. The maximal Cr contamination degree (CD) was 2.01. CD analysis indicated that 69.2% of the surficial soil has not suffered Cr pollution. The total CD was below zero, so surficial soil in Guiyang does not suffer from Cr pollution.