基于物元可拓模型的兰州市主城区公园表土重金属污染评价  

Using the Matter-Element Extension Model to Assess Heavy Metal Pollution in Topsoil in Parks in the Main District Park of Lanzhou City

作　　者：胡梦珺[1] 李春艳 李娜娜 吉天琪 郑登友 HU Meng-jun;LI Chun-yan;LI Na-na;JI Tian-qi;ZHENG Deng-you(College of Geography and Environmental Sciences,Northwest Normal University,Lanzhou 730070,China)

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070

出　　处：《环境科学》2021年第5期2457-2468,共12页Environmental Science

基　　金：甘肃省高等学校科研项目(2018A-009);国家自然科学基金项目(41171018)。

摘　　要：在分析兰州市主城区公园表土重金属含量水平的基础上,采用UNMIX模型对重金属进行来源解析,同时引入Hakanson毒性响应系数修正传统权重,运用物元可拓模型对重金属污染水平进行评价,并将评价结果与内梅罗综合污染指数(PN)和潜在生态风险指数(RI)进行对比.结果表明:(1)研究区公园表土重金属含量均值都高于兰州市土壤背景值,其中Ni、Cu和Co的点位含量超标比例各为100%,Cr、V、Pb和As分别为58.82%、14.71%、20.59%和2.94%.(2)源解析显示研究区公园表土重金属存在3大污染源,源1为建筑业污染源,对Co的贡献率为56%;源2为交通污染源,对Cu和Pb的贡献率各为44%和52%;源3为自然源,对V、Cr、Ni和As的贡献率各为62%、60%、56%和56%,自然源占主导作用.(3)各重金属权重修正效果显著,Cr和V的降幅各为44%左右,而Ni、Cu、Pb、As和Co的修正权重比常规权重有所增加,增幅依次为Co <Pb <Cu <Ni<As,As的权重变化最为明显,增加约188%左右.(4)物元评价结果显示,研究区46%的公园表土为Ⅴ级状态(重度污染),41%为Ⅳ级状态(中度污染),3%为Ⅲ级状态(轻度污染),Co为主要污染因子;物元可拓模型评价结果与PN及RI结果大致相同,说明物元可拓模型可用于土壤重金属污染评价,评价结果准确客观.The UNMIX model was used to analyze the source of heavy metals found to be present in the topsoil of parks in the main district of Lanzhou City.The Hakanson toxicity response coefficient was used concurrently to modify the traditional weights in the model,and the matter-element extension model was used to evaluate heavy metal pollution.The results of the evaluation were compared with the comprehensive pollution index(PN)and potential ecological risk index(RI).The results were as follows.(1)The average heavy metal content in the topsoil at each sampling point was higher than that of the background value of soil in Lanzhou,with the proportion of Ni,Cu,and Co being 100%while the proportion of Cr,V,Pb,and As contents were 58.82%,14.71%,20.59%,and2.94%,respectively.(2)The results of source analysis showed that there were three major sources of heavy metal pollution in the topsoil of the parks in the study area.Source 1 is construction pollution,which contributes 56%of the Co present.Source 2 is traffic pollution,which contributes 44%and 52%of Cu and Pb,respectively.Source 3 is natural,and contributes 62%,60%,56%,and56%of V,Cr,Ni,and As,respectively.Thus,this research showed that natural sources are predominant.(3)The weight correction effect for each heavy metal was significant;there was an approximately 44%reduction in both Cr and V,while the corrected weights of Ni,Cu,Pb,As,and Co increased in the order Co<Pb<Cu<Ni<As compared with the conventional weights.The most obvious change in weight was that of As,which increased by approximately 188%.(4)The results of the evaluation using the matter-element model showed that the state of 46%of the topsoil in the parks in the study area was gradeⅤ(severely polluted),while 41%was gradeⅣ(moderately polluted)and 3%was gradeⅢ(lightly polluted);Co was the main pollutant.The results of the model evaluation were roughly the same as of from the PNand RI,indicating that the matter-element extension model can be used to evaluate heavy metal pollution in soil and the evaluation re

关 键 词：UNMIX模型 物元可拓模型 毒性响应系数 重金属 公园 

分 类 号：X53[环境科学与工程—环境工程]