【作者】 马军；

【导师】 刘爱琴；

【作者基本信息】 福建农林大学 ， 自然地理学， 2010， 硕士

【摘要】 城市边缘区作为城市发展腹地和服务城市人口食品的重要区域,其环境质量的好坏直接影响城市人口身体健康与城市可持续发展。城市边缘区重金属污染不仅破坏生态环境质量,在一定程度上影响动物、农作物生长发育,破坏生态平衡,而且还可以通过食物链等方式进入人体,危害人体健康。研究城市边缘区这一极其复杂环境下多种土地利用方式重金属污染分布对改善城市生态环境,科学合理进行城市边缘区土地利用生态规划,保障人类健康有重大的理论和现实意义。本文在对福州城市边缘区全面踏查基础上,按照典型性与代表性原则,选取闽侯县、鼓楼区、晋安区、马尾区、仓山区的菜地、果园地、水稻田、林地和河流、湖塘、水库为调查对象,共采集200个土壤样品和102个水样,测定了福州城市边缘区水土环境中重金属(Zn、Cr、Mn、Pb、Cu、Cd)含量,从水平和垂直角度分析了不同土地利用方式土壤重金属污染的空间分布特征,比较研究了以DTPA浸提液和HCl浸提液提取不同土地利用类型土壤重金属有效态含量的差异,分析其与全量的相关性。在全面分析水体重金属分布特征的基础上,研究了福州城市边缘区以生活污水为主导污染源的河流水体重金属月动态变化规律。同时分析了水土环境中各重金属间的相关性,分别以国家土壤环境质量标准、福建省土壤环境背景值、绿色食品产地环境质量标准和食用农产品产地环境质量标准为土壤环境质量评价标准,利用内梅罗综合污染指数法、潜在生态风险指数法评价了土壤重金属污染状况和潜在生态风险,以地面水环境质量标准为评价标准对水体污染状况进行了评价。主要研究结果如下:1、对福州城市边缘区不同土地利用方式土壤重金属含量空间分布的研究表明:各土地利用类型土壤重金属含量因地域和重金属种类呈不同的分布特征,菜地和果园土壤重金属平均含量明显高于林地和水稻田,农业生产强度与重金属含量基本呈正比。四种土地利用类型的重金属含量总体表现为:菜地>果园>水稻田>林地,紧靠马尾快安工业组团、金山工业区、城门老工业区和沈海高速福州连接线、104国道、324国道、316国道、203省道、103省道等城市四周对外干道的重金属含量普遍高于其他地区。2、不同土地利用方式土壤重金属垂直分布呈不同的特点。菜地土壤Zn、Cr、Cu、Cd含量随土层深度增加而降低,Mn则相反,Pb没有明显的垂直变化特点;果园土壤Zn和Pb没有明显的垂直变化特征;Cr和Mn含量随土层深度增加呈不同程度的上升趋势,在40-60cm处富集,Cu和Cd没有相对一致的变化规律;林地土壤Zn、Cu平均含量随深度的增加逐渐减少,呈现出0-20cm>20-40cm>40-60cm的变化趋势,Cr、Pb出现20-40cm>0-20cm>40-60cm的变化特点,Mn含量随土层深度加大而不断增加,不同海拔高度的林地土壤重金属含量变化没有一致的特点;水稻田中Zn、Cu等营养元素呈现明显的表层富集,Cr和Mn则表现为在0-20cm土层含量相对最低,分别在20-40cm或40-60cm达到最高值,Pb、Cd没有明显的垂直变化特征。3、距公路不同距离土壤重金属含量分布特征研究表明:菜地各层土壤Zn、Mn含量随着距离公路越远,含量越低,Cr、Pb、Cu、Cd没有明显的变化规律;水稻田土壤Zn含量随距离的变化没有明显的变化规律,Cr含量在距离公路100m的含量高于50m和200m,Mn含量在0-20cm层随距离增大而不断减少,但在20-40cm和40-60cm则随距离的增加含量升高,且土层越深,随距离增大而升高的趋势越明显;Cu、Pb含量随距离的增大呈略微减少的特点,Cd含量基本呈随距离增加而不断升高的特征。4、不同土地利用方式土壤重金属浸提态含量因土地利用方式、元素差异、土层深度的变化和浸提剂的不同而呈现不同的分布特征,四种不同土地利用方式土壤重金属浸提态含量和浸提率都与其全量分布特点一致,即菜地>果园>水稻田>林地,六种重金属浸提态含量和浸提率大致呈0-20cm>20-40cm>40-60cm的变化趋势,DTPA浸提态含量垂直变化与HCl浸提态含量垂直变化特点基本一致,HCl浸提效果比DTPA浸提效果好。5、不同土地利用方式重金属元素间及其与pH相关性研究表明:在菜地和果园土壤中,土壤pH与Mn全量存在极显著正相关,林地和水稻田土壤pH则与重金属无显著相关,四种不同土地利用方式土壤都存在不同程度、不同类型重金属组合的复合污染;不同土地利用方式重金属浸提态含量及其全量间的相关性存在较显著差异;菜地和果园土壤重金属全量与HCl浸提态含量之间的相关性总体上比林地和水稻田土壤的显著,各元素全量与其HCl浸提态含量和DTPA浸提态含量存在不同程度的正相关或负相关。6、水体有机污染研究表明:不同采样断面或监测垂线随NH3-N、COD和总P呈现出不同的分布规律,且存在较大差别,在以生活污染型为主的岐头江,水体自净作用对水体有机污染有一定的减轻和弱化作用,对于常年工业农业废水和生活废水等相结合的污染水体中,水体自净作用对改善水质环境的效果不明显;四种不同土地利用方式水体有机污染大致表现为:湖塘>江河>工业区>水库。7、水体重金属污染现状和动态研究表明:不同重金属元素存在不同程度污染;四种不同土地利用方式水体重金属污染大致表现为:工业区>江河>湖塘>水库;江河水体自净作用对水环境中重金属的分布没有明显效果,在岐头江、乌龙江和闽江都呈现随上游-下游的累积特点。水体重金属污染与工业生产、农业生产、养殖、交通运输等有较密切关系。岐头江水样重金属平均含量的月动态变化显示:Zn、Cr和Cu含量在丰水期高于枯水期,Mn含量则呈相反的分布规律,Pb和Cd的分布没有明显的变化规律。8、分别以国家土壤环境质量标准、福建省土壤环境背景值、绿色食品产地环境质量标准和食用农产品产地环境质量标准为评价标准或参比值对土壤环境质量评价的结果基本一致,四种不同土地利用方式土壤重金属污染现状和潜在生态风险总体表现为:菜地>果园>水稻田>林地;位于工业区、经济开发区、主要交通线沿线附近的土壤重金属污染明显更加严重,污染的潜在生态风险更大;此外,由于福建土壤环境背景值中重金属限值较低,以福建省土壤环境背景值为评价标准或参比值所得出的结果污染程度更大、污染潜在生态风险更大。9、以地表水环境质量标准为评价依据,对福州城市边缘区各主要水域中9个水质指标进行评价结果发现各水域都存在不同程度的有机污染和重金属污染,且以NH3-N、COD、Pb、Cr污染最为突出,各指标的水质分级结构也有较明显的差异。更多还原

【Abstract】 Urban fringe plays an important role in the development of city and the food service of people.The quality of environment has great influence on the health of people and city sustainable development.Urban fringe heavy metal pollution not only destroys ecology such as animals and crop, but also does harm to human health by food chain.The study of the distribution of heavy metal pollution in urban fringe has great theoretical and practical significance,and it is important for us to make a good plan for land use of urban fringe and to keep human health.Based on complete investigation of urban fringe in Fuzhou, the article choosed vegetable plot,orchard, rice field,woodlot,stream,pool and reservoir in Min hou,Gu lou,Jin an,Ma wei,Cang shan as research objects. The experiment collected 200 soil samples and 102 water samples and determined the content of heavy mental (Zn,Cr,Mn,Pb,Cu,Cd). The spatial distribution of heavy metals in different land use was analyzed from the horizontal and vertical angle. Difference among DTPA extraction or HCl extraction in different land use was compared, so was its correlation with the whole amount.On the basis of overall analysis of the heavy mental distribution in water,the regulation of month dynamic change about the stream which was mainly polluted from domestic sewage was studied,and the correlation with all kinds of heavy mental was studied too.Using national soil environmental quality standard,Fujian soil environmental background values,green food product locality environmental quality standard and edible agricultural products environmental quality standard as soil environmental quality standards, this paper evaluated heavy metal pollution status and potential ecological risk in different land use soils\water by the N.L.Nemerow comprehensive pollution index and potential ecological risk index.The main results were as follows:(1)The study of spatial distribution characteristic of heavy metals in different land use in Fuzhou urban fringe showed that the content and the kind of the heavy metal varied in different land use regions: The contents of heavy metal in vegetable plot and orchard were much higher than that in woodlot and rice field.The contents of heavy metal were proportional to intensity of agricultural production.The contents of heavy metal in four kinds of land use generally showed:vegetable plot>orchard>rice field>woodlot. Contents of the heavy metals in samples from lands around Fuzhou city(Kuaian industrial area in Mawei,Jin shan industrial area,Cheng men industrial area and Fu zhou high-speed line of Shen hai highway,104,324,316 national road and 203,103 provincial road etc )were general higher than those in other areas.(2)The contents of soil heavy metals varied in vertical distribution in different land use. The contents of Zn,Cr,Cu,Cd decreased as soil layer increased in vegetable plot,while the content of Mn was opposite to those, content of Pb was with no significant change in vertical distribution. In orchard, the contents of Zn and Pb were with no significant change in vertical distribution, while the contents of Cr and Mn increased to certain extent as the soil layers increased,with enrichment in 40-60cm,the contents of Cu and Cd were with no similar change law.In woodlot,the average content of Zn and Cu decreased gradually as the soil layers went deeper.The change law showed with 0-20cm>20-40cm>40-60cm,while the content of Cr,Pb showed with 20-40cm>0-20cm>40-60cm.The content of Mn increased as the soil layers went deeper.The content of soil heavy metal was with no similar change law as altitude varied.In rice field, the content of Zn,Cu showed significant enrichment in surface layer. The content of Cr and Mn was lowest in 0-20cm soil layer,the maximum value was in 20-40cm or 40-60cm respectively. The content of Pb,Cd was with no significant change in vertical distribution.(3) The study on the content of soil heavy metal distribution with different distance from road showed: In orchard,the farer distance from the road the lower content of Zn,Mn was in each layer,but there was no significant change in the content of Cr,Pb,Cu,Cd.In rice field, there was no significant change in the content of Zn as the distance changed, but the content of Cr from 100m distance was higher than that which was from 50m and 200m.On 0-20cm layer,the content of Mn decreased as the distance got farther,but it both increased on 20-40cm and 40-60cm as the distance got farther,and the deeper layer was,the farther distance was,the more significant growth trend was.The content of Cu,Pb decreased slightly as the distance got farther. The content of Cd increased as the distance got farther.(4)There were different soil heavy metals distribution among different land use,different elements\different soil depth,different extracting agent.Both the extraction content of soil heavy metals in different land use and extraction rate were consistent with its total content: vegetable plot>orchard>rice field >woodlot, the extraction content of soil heavy metals and extraction rate showed with 0-20cm>20-40cm>40-60cm.Content of DTPA extraction was consistent with that of HCl extraction.And HCl extracting effect was better.(5)The study on correlation between land use and heavy metal elements showed: there was a significantly positive correlation between soil PH and total Mn in vegetable plot and orchard;while there was no significant correlation between soil PH and total Mn in woodlot and ricefield.There were combined pollution (with different heavy metals) by different degree in each land use.There was a quite significant difference between heavy metal extraction and heavy metal total content in different land use:The correlation between heavy metal HCl extraction and heavy metal total content in vegetable plot and orchard were higher than those in woodlot and rice field. There was positive,negative correlation among heavy metal total content,HCl extraction\DTPA extraction to some different degree.(6)The study on water organic pollution showed: Different sampling section showed different distribution law with NH3-N,COD and total P change.The self-purification of the stream water alleviated and weakened water organic pollution which mainly polluted by domestic sewage, while the self-purification did not play an importanr part in improving quality of water environment; water organic pollution in four different land use showed:Pool>stream>industrial area>reservoir.(7)Dynamic study on water heavy metal pollution status showed: There are different levels of different heavy metals pollution.The general result showed: industrial area>stream>pool>reservoir. The self-purification of the stream water did not play an importanr part in the distribution of water heavy metals which enriched from upper to downstream among Qitou river,Wu long river,Min river. There was close relationship between water heavy metals and industrial production, agricultural production, culture,transportation etc. The average content of heavy metal monthly dynamic change in Qitou river showed: the content of Zn,Cr and Cu in wet season were higher than those in dry season while the content of Mn was in opposite distribution.The content of Pb,Cd was with no significant change.(8)According to certain evaluation standards of national soil environmental quality standard,Fujian soil environmental background values, green food product locality environmental quality standard and edible agricultural products locality environmental quality standard,the result was basically identical.The general results of the soil heavy metal pollution status and potential ecological risk in four different land use showed with vegetable plot>orchard>rice field>woodlot;lands located in indusrial area,economic development zone,main traffic line were much more seriously polluted by heavy mentals and with higher potential ecological risk.Besides, the threshold of heavy metals according to Fujian soil environmental background values was lower,so the results showed that the pollution and potential ecological risk was much more severe.(9) In this paper we took environmental quality standards of surface water as evaluation basis and evaluated 9 water quality indexs of main waters in urban fringe of Fuzhou.The result showed that there were organic pollution of heavy metals inordinately in all waters,and Pb,Cr,Cd and COD pollutions were the most outstanding, what was more ,each index of water quality hiberarchy had obvious differences.更多还原