【作者】 仝致琦；

【导师】 马建华；

【作者基本信息】 河南大学 ， 环境地理学， 2013， 博士

【摘要】 公路建设在带动经济发展的同时，也导致了一些环境问题，并引起学术界的广泛关注。本文运用系统科学理论与方法，将路域环境各因素看作是相互联系的统一整体，从重金属“源→路径→汇→影响”角度出发，研究交通源重金属迁移及对路域环境的影响。以河南省公路（G310、S337）为例，采集路旁土壤、小麦、水稻、大气颗粒物、降水、地表水样品，用ICP-MS分析其Cd、Cr、Cu、Ni、Pb、Zn等重金属含量。对不同耕作方式下路旁土壤重金属含量进行泛克里格插值分析，开展路旁土壤、小麦、水稻、地表水公路源重金属含量、分布、污染状况和风险评价，从线源颗粒物扩散模型出发，对路旁大气颗粒物和路旁土壤重金属空间分步进行拟合，较好地揭示了路源重金属迁移和沉降规律。经研究，得出以下主要结论：（1）公路交通对路域土壤、水体、生物、大气环境都有重大影响。公路源重金属产生后，赋存于大气颗粒物中，随其进行干湿沉降，最终通过干湿沉降汇于地表水及土壤，引起路域环境重金属积累，甚至发生污染。建立公路源重金属迁移模型和路旁土壤重金属空间分布模型，并使用大气颗粒物、大气颗粒物重金属及土壤重金属含量进行模型验证。该模型对于大气颗粒物、大气颗粒物重金属含量实测值拟合效果较好，对土壤重金属含量实测值拟合效果很好。（2）耕作方式及重金属特性对路旁土壤重金属空间分布具有强烈影响。克里格空进插值分析表明，杏花营断面旱旱轮作的路旁土壤重金属呈现出与道路平行的条带状空间分布，其中Cr和Cu含量呈指数递减分布，Pb、Ni、Zn和Cd呈偏态分布，峰值出现在距路基30～50m之间。重金属分布类型与该元素主要赋存的大气颗粒物粒径有关，赋存于较大颗粒物上的重金属在道路两侧呈指数递减分布模式，相反则呈偏态分布模式。与此相反，杜良段面水旱轮作的土壤重金属含量呈斑点状或斑块状分布，与距路基距离的相关性较差。这主要是淹水条件增强了重金属水平迁移所致。（3）路旁土壤环境已发生不同程度重金属污染，存在一定的潜在生态风险、健康风险。以国家土壤环境二级质量标准为基准的重金属污染指数法评价表明，杏花营断面和项店断面路旁土壤重金属单项、综合污染均为安全级别；杜良断面土壤Ni在路基100m（南侧）和500m（北侧）范围内达到轻度污染，Zn在距路基140和150m（南侧）处的样点达到轻度污染，Cu、Cd、Pb和Cr均为安全级别，杜良断面土壤重金属综合污染总体为安全级别。以对照样土壤重金属含量为基准的地积累指数评价表明，土壤6种重金属均出现不同程度的污染。杏花营断面南侧土壤Cr在距路基0～30m之间达到中度污染，35～120m之间达到轻度污染；北侧土壤Cr在距路基15m左右达到中度污染，0～10、20～120m之间达到轻度污染；杏花营断面Cu、Zn、Ni、Cd和Pb的轻度污染带出现在距路基80m范围之内。杜良断面土壤Pb、Ni、Zn、Cr、Cu出现局部区域的中度污染，Cd造成局部区域的轻度污染；项店断面土壤Cr、Ni、Zn、Cu、Cd局部达到轻度污染，Pb为安全级别。以对照样土壤重金属含量为基准的潜在生态风险指数评价表明，杏花营土壤Cd达到中等生态风险的样点数占总样数的82.43%，杜良断面为45.07%，项店断面为87.83%；杜良断面土壤Pb达到中等生态风险的样点数占总样点的8.45%，其余样点均为轻微风险。3个断面土壤均存在重金属综合潜在生态风险。3个断面土壤重金属的单项和综合非致癌和致癌健康风险甚小，可忽略。（4）G310公路两侧200m范围内粮食作物（水稻、小麦）重金属含量显著高于对照样点。样点小麦籽粒Cr、Ni和Pb全部污染，其中Pb属于重度污染，Cr达到轻度污染、中度污染和重度污染的样点数分别占总样数的2.70%、16.22%和81.08%，Ni达到轻度污染、中度污染和重度污染的样点数占总样数分别为8.11%、40.54%和51.35%，Cu、Cd和Zn达到分轻度污染的样点数占总样数的89.19%、9.11%和45.95%。水稻Cr为重度污染，Ni达到轻度污染、中度污染和重度污染的样点数分别占总样数的19.44%、16.67%和11.11%；Pb达到轻度污染的样点数占总样数的25.00%；Cu、Zn和Cd为未污染。小麦籽粒综合污染指数达到重度污染水平。水稻籽粒重金属多为中度污染，部分达到重度污染。小麦Cr、Pb存在非致癌健康风险，Cu、Cd、Zn和Ni无明显的非致癌健康风险，有综合非致癌健康风险，小麦Cr风险占总风险的52.16%，为主要非致癌风险因子，Pb风险占总风险的26.59%，为次要风险因子。水稻Cr存在非致癌健康风险，Cu、Pb、Zn、Cd和Ni无明显的非致癌健康风险，Cr风险占总风险82.90%，也是主要非致癌风险因子。小麦和水稻的Cr、Pb存在非致癌健康总风险，Cu总体存在健康总风险，Zn、Cd和Ni的不存在健康总风险，小麦和水稻存在重金属综合非致癌健康总风险。（5）与对照样点相比，距路基200m范围内的地表水体6种重金属含量显著升高，造成部分地表水环境的污染。地表水Cu达到轻度污染、中度污染和重度污染的样点数分别占总样数的16.67%、8.33%和8.33%；Zn达到轻度污染的样点数占总样数的4.17%。路域降水中的重金属含量也高于对照样点，但没有造成污染。（6）路域大气颗粒物迁移距离与其粒径呈负相关，粒径越小，迁移越远。大气颗粒物重金属含量空间分布有指数和偏态两种分布类型，其中Pb和Cr属于指数递减分布趋势，Cd、Cu、Ni和Zn属于偏态分布。重金属所赋存颗粒物粒径从大到小依次为Cd=Cu>Cr>Ni>Pb。路域大气环境出现Pb的中度或重度污染，颗粒物的粒径越小，污染程度越重。路域大气颗粒物重金属存在综合非致癌和致癌健康风险，Cr为主要健康风险因子。更多还原

【Abstract】 Although the road is one of the important powers of economic progress, development of road also caninduce a lot of environmental problems. In the past few decades, these environmental problems are alwayshot topic. In the study, on the basis of ‘source-path-acceptor-effect’ of heavy metals, environmental effectsand migration rule of traffic-source heavy metals were investigated, using theories and methods of SystemScience.310thNational Highway and337thProvincial Highway were chosen as the research objects.Roadside soils, wheat, rice, ambient particulate matter, precipitation andsurface water were collected assamples, and their heavy metals (Pb, Cu, Ni, Cr, Cd and Zn) were detected by the inductively coupledplasma mass spectrometry (ICP-MS) respectively according to the recommended standard method. Spatialdistribution of heavy metals concentrations by applying Universal Kriging interpolation model,concentration, PollutionIndex&Risk Index of heavy metals in soils, wheat, rice, ambient particulate matter,precipitation&surface water were analysed. Meanwhile, roadside atmospheric particulate and the spatialconcentration distribution of roadside heavy metals was fitted using line source particle diffusion model.The main results were as follows:(1) Highway traffic has great effect on heavy metals in soil, plant, airand water in road-domainenvironment. Since the traffic-source heavy metals appear, they are adsorbed by and migrate with ambientparticulate matters, finally, they are imported into soils and water. As a result, traffic-source heavy metalshave been accumulated in road-domain environment, and caused environment polluted. The models ofmigration in air and spatial distribution in soils for traffic-source heavy metals were built, and verified bythe measured concentrations. The spatial distributions of ambient particulate matter&its heavy metalconcentrations were well fitted by the model, and the spatial distributions of soil heavy metalconcentrations were better fitted by.(2) The different tillage systems and characteristics of heavy metals have great effects on spatialdistribution of heavy metals in roadside soils.The distributions of metal concentrations in upland-uplandrotationfield were strips parallel to the highway stretching. The concentrations of Cr and Cu decreasedexponentially with the distance from the roadbed, however, the concentrations of Cd, Pb, Ni and Znrevealed an asymmetrical distribution with the distance, which increased firstly, reached their highest values between30and50m away from the roadbed, and then gradually decreased to the control values.Distribution types have significant relationship with sizes of ambient particulate matters whichtraffic-source heavy metals are adsorbed by. Being adsorbed by the larger ambient particulate matters,heavy metal concentrations reveal an exponential distribution. While they are adsorbed by the smaller ones,their concentrations reveal an asymmetrical distribution. In contrast, heavy metal concentrations showedirregular patch distribution in paddy-upland rotation field, resulted from waterlogged condition changingpH, Eh of soils, leading to horizontal migration of soil heavy metals.(3) Traffic-source heavy metals have posed pollution, certain potential ecological risk and health riskon road-domain soil environment. According to the second index in the national standards for soil quality,the assessment by pollution index indicates that it was in not polluted states on Xinghuaying&Xiangdiantransect. On Duliang transect, Ni was in light polluted states within100meter away from the roadbed onthe south side, and within500meter on the north side. Zn was in light polluted at the position of140&150meter away from the roadbed on the south side. The others were in not polluted states. Totally, heavymetals were in comprehensive not polluted state on the three transects. Making a reference to the controlvalues, the assessment by geoaccumlation index of heavy metal shows that six heavy metals were indifferent polluted states. On Xinghuaying transect, Cr was in middle polluted states within30meters, andin slight polluted states between35~120meters away from the roadbed on the south side. Cr was in middlepolluted states at the position of15meter, and in slight polluted states between35~120&20~120metersaway from the roadbed on the north side. Cu, Zn, Cd and Pb appear light polluted at some positions within80meters away from roadbed on both sides. On Duliang transect, Pb, Ni, Zn, Cr and Cu were in middlepolluted states in part regions, Cd was in light polluted in part regions. On Xiangdian transect, Cr, Ni, Zn,Cu and Cd were in middle polluted states in part regions, Pb was in light polluted in part regions. Making areference to the control values, the assessment by potential ecological risk index of heavy metals shows thatthere was comprehensive milddle potential ecological risk on all transects. Cd in middle potentialecological risk states was82.43%on Xinghuaying transect,45.07%on Duliang transect, and87.83%onXiangdian transect. Pb in middle risk state was8.45%on Duliang transect. While, all the others were inlight risk states. CR and TCR on all transects were lower than the standard suggested by US EPA whichmeant where may be carcinogenic riskpossibility, and Cr is the main factor of potential ecological risks. (4) The concentrations of heavy metals in grain crops within200m away from roadbed weredistinguishably higher than the control values. Pb in wheat samples were all in heavy polluted states. Thewheat sample number of Cr achieving slight polluted state, middle pollutedstate and heavy polluted staterespectively accounted for2.70%,16.22%and81.08%of the total sample number. The wheat samplenumber of Ni achieving slight polluted state, middle polluted state and heavy polluted state respectivelyaccounted for8.11%,40.54%and51.35%. While the wheat sample number of Cu, Cd&Pb achievingslight polluted state respectively accounted for89.19%,9.11%and45.95%. Cr in rice samples were all atheavy polluted state. The rice sample number of Ni achieving slight polluted state, middle pollutedstate andheavy polluted state respectively accounted for19.44%,16.67%and11.11%of the total sample number.Therice sample number of Pb achieving slight polluted state accounted for25.00%. While Cu, Cd&Znwere in not polluted state.The metals in wheat had comprehensive heavy polluted index, and the metals inrice partly had comprehensive midlle polluted index, partly had comprehensive heavy polluted index. Cr&Pb in wheat had non-carcinogen risk possibility, while Cu、Cd、Zn&Ni had not non-carcinogen riskpossibility. Heavy metals in wheat had comprehensive non-carcinogen risk possibility. Cr in wheat is thefirst main factor of non-carcinogen risk possibility, for the risk of Cr accounted for52.16%of the total risk.And Pb is the second main factor of non-carcinogen risk possibility, for the risk of Cr accounted for26.59%of the total risk. Cr in rice had non-carcinogen risk possibility, while Pb, Cu, Cd, Zn&Ni had notnon-carcinogen risk possibility. Heavy metals in rice had comprehensive non-carcinogen risk possibility. Crin rice is main factor of non-carcinogen risk possibility, for the risk of Cr accounted for82.90%of the totalrisk. Cr&Pb in wheat&rice had non-carcinogen risk possibility, while Cu, Cd, Zn&Ni had notnon-carcinogen risk possibility. Heavy metals in wheat&rice had comprehensive non-carcinogen riskpossibility.(5) Highway traffic had great effect on road-domain water environment. The concentrations of heavymetals in surface water200m away from roadbed were distinguishably higher that the control values, evenpart of surfacewaterhad been polluted. The surfacewater sample number of Cr achieving slight pollutedstate, middle pollutedstate and heavy polluted state respectively accounted for16.67%,8.33%and8.33%of the total sample number. And the number of Zn achieving slight polluted state accounted for4.17%.Highway traffic had great effect on roadside precipitation but it did not cause roadside precipitation polluted.(6) Ambient particulate matter in road-domain environmentwas mainly affected by wind direction androad towards. The migration distance of ambient particulate matter is negatively correlated with its size.The larger ambient particulate matter is the nearer its migrationis. The effects of atmospheric particulate onspatial distributions of heavy metals mainly occurred in the downwind region of road-domain environment.They revealedtwo type distributions: exponentialdistribution (Pb&Cr)&skew distribution (Cd, Cu, Ni&Zn). The sizes of atmospheric particulate, absorbing heavy metals, are in decreasing order ofCd=Cu>Cr>Ni>Pb. Pb achieved middle or heavy polluted state in road-domain environment, and thesmallerambient particulate matter is, the more serious its pollutionis. Heavy metals of ambient particulatematter hadcomprehensive non-carcinogen (carcinogen) risk possibility, and Cr is main factor ofriskpossibility.更多还原