改进模糊数学法在土壤重金属污染评价中的应用

在土壤重金属污染评价中,重金属污染因子权重是影响土壤环境质量评价结果的关键因素。以花溪区城郊菜地土壤中Zn、Cd、Pb、Cu、As和Hg为污染因子,运用最小信息熵原理,将"超标倍数法"与"双权重超标赋权法"组合成综合权重以改进传统模糊综合评价模型。改进模型结果显示,31个采样点处于Ⅰ级,13个采样点处于Ⅱ级。相比于传统模糊综合评价模型,在计算评价因子权重时,改进模糊综合评价模型综合了重金属浓度及其毒性,使评价结果更为客观、合理。利用Arc GIS 9.3软件进行土壤重金属污染空间分布结果表明,花溪区城郊菜地土壤清洁率达到83.87%,尚清洁率为16.13%,尚未出现土壤污染区。

Application of fuzzy mathematical model in pollution evaluation of soil heavy metals

Determining weights of heavy metal contamination is important in the soil environment quality assessment.Used Zn,Cd,Pb,Cu,As and Hg in suburban vegetable soil of Huaxi district as the pollution factors and applied the principle of minimum relative information entropy.This study employed "the excessive multiplier method" and "the double weight excessive weighting method" as a set of combined weight factors,which was used to optimized fuzzy comprehensive evaluation model.Results showed that 31 sampling points in the Class Ⅰ and 13 sampling points in the Class Ⅱ.Compared with the traditional fuzzy comprehensive evaluation model,the optimized fuzzy comprehensive evaluation model which integrates the heavy metals concentration and toxicity level when calculated weight of pollution factors,and the evaluation results of optimized model are more objective and reasonable.The space distribution of soil heavy metals pollution was analyzed by ArcGIS 9.3,the calculated results showed that the research area soil clean ratio reached 83.87％ and moderately clean ratio was 16.13％,soil pollution area not yet appeared