基于三角模糊数和重金属化学形态的土壤重金属污染综合评价模型

将三角模糊数理论引入环境评价领域,构建了量化表征不同重金属自身生物毒性及同一重金属不同化学存在形态生物毒性的土壤重金属生物毒性双权重评价体系,并结合地累积指数评价模型,建立了土壤重金属污染综合评价模型.最后,采用该综合评价模型评价了寺庄顶典型污灌区的土壤重金属污染状况.评价结果表明,寺庄顶典型污灌区土壤中5种重金属的综合污染评价值差异较大,各重金属的综合污染程度排序为:Cd＞Ni＞Cu＞Zn＞Cr,Cd、Ni、Cu应成为今后该地区土壤污染治理的主要控制因子.与确定性模型评价结果的对比分析表明,综合评价模型较好地弥补了确定性评价的不足,并能更全面、真实地综合表征评价区域土壤重金属富集污染和潜在生物毒性风险信息,为科学决策提供了理论基础.

An integrated assessment model for heavy metal pollution in soil based on triangular fuzzy numbers and chemical speciation of heavy metal

The triangular fuzzy numbers theory was introduced to environmental assessment system.Double weighting system of heavy metal biology-toxicity was designed,which could characterize the biology-toxicity of different heavy metals and the biology-toxicity of different chemical speciation of every single heavy metal quantitatively.Afterwards,an integrated assessment model based on the index of geo-accumulation was built.As a model case,the soil pollution of heavy metal in Shizhuangding typical sewage irrigation area was selected to test and verify the integrated assessment model.The results showed that the integrated assessment value of the 5 heavy metals were markedly different,while their integrated pollution degree were in the order Cd>Ni>Cu>Zn>Cr,and the Cd,Ni and Cu would be the primary pollution controlling factors in Shizhuangding typical sewage irrigation area.Compared with the result of the certain assessment model,it was concluded that the integrated assessment model overcame the shortcomings of the certain assessment model,by conveying information about both degree of heavy metal enrichment and potential biological risk of heavy metal pollution in soil more accurately which provided the basic theory to scientific decision-making.