基于三角模糊数的中国省会城市土壤重金属污染风险评价

Risk Assessment of Heavy Metal Pollution to Soils in Chinese Provincial Capital Cities Based on Triangular Fuzzy Numbers

收集整理了中国33个省会城市(除中国台北)的表层土壤6种重金属(As、Cr、Cu、Pb、Zn和Cd)含量。针对城市土壤重金属含量数据的模糊性和评价参考标准选择过程中的不确定性,将三角模糊数理论引入城市土壤重金属污染评价领域,对其含量和评价标准进行表征,结合地累积污染指数法,建立了基于三角模糊数的城市土壤污染评价模型,并采用该模型评价了中国省会城市土壤重金属污染状况。结果表明:研究区域中6种重金属污染的总体水平较低,均属于轻度和偏中度污染水平,按污染程度由大到小的排序为:Cd>Pb>Cu>Zn>Cr>As。其中Cd的评价结论模糊性较高,表明其可能存在局部性污染,应该引起重视。与确定性模型评价相比,该评价模型较好地弥补了确定性评价模型的不足,评价结论更加准确、全面、合理,能较好地反映研究区域的重金属污染状况。

The contents of six heavy metals(As,Cr,Cu,Pb,Zn and Cd)in topsoil of 33 provincial capital cities in China(except Chinese Taipei)were collected and sorted.In view of the fuzziness of urban soil heavy metal content data and the uncertainty in the selection of evaluation reference standards,the triangular fuzzy number theory was introduced into the urban soil heavy metal pollution evaluation to characterize their contents and evaluation standards.Combined with the cumulative pollution index method,the urban soil pollution evaluation model based on triangular fuzzy number was established,and the pollution status of heavy metals in the soil of the provincial capital cities was evaluated by using this model.The results show that the overall pollution level of six heavy metals in the study areas is low,belonging to mild and moderate pollution levels.According to the degree of pollution from heavy to light,the order of six heavy metals is:Cd,Pb,Cu,Zn,Cr,As.Among them,the evaluation conclusion of Cd is fuzzy,indicating that it may have local pollution,which should be paid attention to.Compared with the deterministic model evaluation,this evaluation model better makes up for the lack of deterministic evaluation,and the evaluation conclusion is more accurate,comprehensive and reasonable,which can better reflect the heavy metal pollution situation in the research areas.