【作者】 林晓峰；

【导师】 胡恭任；

【作者基本信息】 华侨大学 ， 环境科学， 2011， 硕士

【摘要】 随着城市化的推进,人类活动将大量的污染物带入城市环境中,造成了城市环境污染,其中以城市土壤重金属污染最为严重。城市土壤重金属通过地面扬尘、食物链传递等途径破坏城市生态环境,危害人类健康。本文以泉州市城市表层土壤(0~15cm)为研究对象,将研究区划分为交通区、商业区、城市绿地、居民区和工业区5个功能区,采集了47个表层土壤样品,分析测试了18种重金属元素,评价了重金属污染程度,并探讨了其可能来源,得到的主要结论如下:(1)运用数学统计分析方法,研究了泉州市城市表层土壤18种重金属元素的含量特征。结果表明,每种重金属元素在土壤中都有一定程度的富集;而以重金属Mn、Sb、Sn、Cd、Pb、Zn、Cu、Hg、Ni的富集程度较高,其含量远高于土壤环境背景值。(2)以泉州市土壤环境背景值为评价基准,分别运用地累积指数法和潜在生态危害指数法评价了泉州市城市表层土壤重金属的污染程度。地累积指数法评价结果表明,Sb、Hg污染程度最高,工业区的污染程度要明显高于其他功能区,18种重金属元素污染程度高低排序为:Hg>Sb>Ni>Sn>Co>Zn>Pb>Li>Cd>Bi>Mn>Cr>As>Fe>V>Cu>Sc>Ti。潜在生态危害指数法评价结果表明,Cd和Hg是最主要的生态风险贡献因子,12种重金属元素的生态危害等级排序为:Hg > Cd >Cu> Pb>Ni>As>Zn> Co>Cr>V>Mn>Ti;各功能区潜在生态危害排序为:工业区>城市绿地>商业区>交通区>居民区。(3)以国家土壤环境质量标准(GB15618-1995)为标准,运用模糊数学综合评价模型,以Cd、Hg、As、Cu、Pb、Cr、Zn和Ni 8种重金属作为评价因子,对泉州市城市土壤环境质量进行了评价。结果表明,Cd是土壤的主要污染元素;泉州市城市土壤环境质量为Ⅲ级,达到了比较高的污染等级。(4)运用美国EPA推荐的人体健康风险评价模型,对泉州市城市表层土壤中8种重金属(Cd、Hg、As、Cu、Pb、Cr、Zn、Ni)进行了人体健康风险评价。结果表明,在口鼻摄入和皮肤接触两种暴露途径下,8种重金属的健康风险水平都在风险阈值范围内,不会对人体(成人和儿童)产生健康危害。(5)运用因子分析法对泉州市城市表层土壤中18种重金属元素的可能来源进行了探讨。因子分析结果表明,重金属Sb、Bi、Sn、Pb、Cu、Zn主要来自交通污染和工业污染, Cd则来自工业污染和化肥施用;As、Hg主要来自化石燃料的大量使用和燃煤;Fe、Co、Ni、Cr、Li、Sc、Mn等则来源于成土母质。更多还原

【Abstract】 With the development of the urbanization, the human activity imports a large amount of pollutants into the urban environment, provoking some serious environmental problems. Among those, the pollution of heavy metal in urban soils is the most serious. The heavy metals in urban soil which are transported through ground dust and food chain may destroy the urban entironment seriously, and even may do harm to the human’s health.In the paper, the topsoil of Quanzhou City was regarded as the research object. The survey region was divided into five zones as traffic zone, commercial zone, residential zone, urban green land and industrial zone.47 urban topsoil samples were collected, and 18 kinds of heavy metal elements were analyzed to assess the pollution degree of heavy metals and to discuss their probable sources. The results of the study shows:(1) The concentration characteristics of heavy metals in the urban topsoil of Quanzhou City were analyzed using the statistical software SPSS. The result showed that each heavy metal element has certain enrichment; Mn, Sb, Sn, Cd, Pb, Zn, Cu, Hg, Ni wre much higher than their background values of the local soil environment.(2) Based on the background values of local soil, the heavy metal pollution in the urban topsoil of Quanzhou city was estimated using the Geoaccumulation Index and Potential Ecological Risk Index. The results showed that Sb and Hg were much higher dangerous than other pollutants. The Geoaccumulation Index order of different heavy metals was Hg>Sb>Ni>Sn>Co>Zn>Pb>Li>Cd>Bi>Mn>Cr>As>Fe>V>Cu>Sc>Ti; and the Potential Ecological Risk Index order was Hg>Cd>Cu>Pb>Ni>As>Zn>Co>Cr>V>Mn>Ti. From the functional zones, the pollution consequence was industrial zone > traffic zone > commercial zone > urban green land > residential zone.(3) Based on the environmental quality standard for soils (GB15618-1995), Fuzzy Comprehensive Evaluation was used to estimate the soil environment quality of Quanzhou City. The results showed that Cd was the main pollutant, and the degree of soil environment quality of Quanzhou was gradeⅢ, which meaning a relatively high level of pollution.(4) Using Health Risk Assessment Model was used to estimate the individual health hazard from the heavy metal pollutants. The analysis shows that the non-cancer hazard indexes and carcinogen risks of metals were both lower than their threshold values. The order of non-cancer hazard indexes of heavy metals in soil was Cr>Pb>Cu>Zn>Hg>Ni, and the order of carcinogen risks of heavy metals was As>Cd. (5) The Factor Analysis was used to predicate the potential sources of heavy metals in the urban topsoil of Quanzhou City. The results showed that Sb, Bi, Sn, Pb, Cu and Zn mainly originated from traffic and industrial contamination; Cd originated from industrial and fertilizer; fossil fuel using and coal-fired were the main sources of As and Hg; Fe, Co, Ni, Cr, Li, Sc and Mn were mainly controlled by natural factors, and they originated from natural sources.更多还原