Determination of metal accumulation in deposited street dusts in Amman, Jordan

Street dust samples (120 in total) were collected under stable weather conditions during the hot, dry season (August and September) of 2004 from six different localities (industrial, heavy traffic, medium traffic, light traffic, low traffic and rural) in greater Amman, the capital of Jordan. The concentrations of Fe, Cu, Cd, Pb, Zn and Ni in the dusts were determined by atomic absorption spectrophotometry. The high concentrations of Pb, Fe and Zn in the street dust samples were related to both anthropogenic (industrial sources combined with traffic sources) and natural sources. Surprisingly, the concentrations of Cd in the dusts were low. Correlation coefficient analysis and principle component analysis identified three main sources of these elements and the corresponding distributions. The elements Pb, Zn, Cd, Fe, Cu and Ni were mainly derived from industrial sources, with Pb and Zn additionally derived from traffic sources. The street dusts were found to have highly elevated levels of Zn, particularly along the main trunk roads, indicating that the Zn in the street dusts may be derived from traffic sources, especially vehicle tyres. The concentrations of metals in the different street dust samples were found to vary depending on the density of traffic.     

北京市地面街尘与径流中重金属的污染特征（Characteristics of Heavy Metals in Street Dusts and Urban Runoff in Beijing）

街尘作为城市各种污染物的载体和地表径流污染物的主要来源对水环境的影响日益受到关注.论文分析了北京市城区街尘与地表径流中重金属浓度和颗粒的粒径分布.结果表明:不同城市土地利用类型对街尘和径流中的重金属含量、颗粒粒径分布具有重要影响.在商业区、主要道路、住宅区、城中村4种土地利用类型中,街尘重金属浓度和地面单位面积重金属质量均以主要道路最高;径流重金属浓度由高到低顺序依次为:主要道路>城中村>居民区;主要道路和商业区街尘颗粒中细粒径占的比例较高,在全部土地利用类型的径流水样中颗粒物粒径分布差别不大;随着街尘中颗粒物粒径的减小,重金属浓度增加;街尘中小于149μm的颗粒物质量百分比和重金属浓度均较高,且在径流中这个粒径段的颗粒物含量也高,体积比达80%以上.建议在今后的城市街尘面源污染控制中应特别关注土地利用类型和街尘粒径的影响.     

Sequentielle Schwermetallextraktion aus Staubniederschlägen und Stra\ensedimenten

For the application of our method for the sequential extraction of heavy metals from microsamples presented in part 1 (“Sequentielle Schwermetallextraktion von Mikroproben” — “Sequential Extraction of Heavy Metals from Micro Samples”) an investigation was carried out to evaluate airborne dust fallout and street sediments at two urban sites where different heavy metal immission rates occur due to traffic influence. In the street sediments the total concentrations of zinc, copper and lead was three to fivefold higher in the silt and clay fraction (< 63 μm) than in the particle size fraction (< 1,12 mm), but showed nearly the same mobilisation behaviour. The dust samples showed equal mobilisation behaviour as the street sediments for copper and lead, while zinc was considerably more mobile in the dust samples: In extraction steps I–IV (I: mobile fraction; II: easily deliverable fraction; III: fraction bound to manganese oxides; IV: fraction bound organic to matter) zinc, copper and lead in street sediments, as well as copper and lead in dust samples, were dissolved to 40–70%, whereas about 80% of zinc in the dust samples was already dissolved in extraction step I.     

Contamination levels and human health risk assessment of toxic heavy metals in street dust in an industrial city in Northwest China

This study investigated the content, distribution, and contamination levels of toxic metals (Cd, Cr, Cu, Pb, and Zn) in street dust in Lanzhou, an industrial city in Northwest China. Meanwhile, the risk these metals posed to the urban ecosystem and human health was also evaluated using the potential ecological risk index and human exposure model. Results showed that concentrations of these metals in the dust are higher than the background value of local soil, with Cu having the highest levels. The districts of Anning and Xigu had the most extreme levels of contamination, while Chengguan and Qilihe districts were lightly contaminated, which can be partly attributed to human activities and traffic densities. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Lanzhou were generally at moderate or low levels. Heavy metal concentration increased with decreasing dust particle size. The pollution indices of Cr, Cd, Cu, Pb, and Zn were in the range of 0.289–2.09, 0.332–2.15, 1.38–6.21, 0.358–2.59, and 0.560–1.83 with a mean of 1.37, 1.49, 3.18, 1.48, and 0.897, respectively. The geo-accumulation index (I _geo) suggested that Zn in street dust was of geologic origin, while Cd, Cr, Pb, and Cu were significantly impacted by anthropogenic sources. The comprehensive pollution index showed that urban dust poses a high potential ecological risk in Lanzhou. Non-carcinogenic and carcinogenic effects due to exposure to urban street dust were assessed for both children and adults. For non-carcinogenic effects, ingestion appeared to be the main route of exposure to dust particles and thus posed a higher health risk to both children and adults for all metals, followed by dermal contact. Hazard index values for all studied metals were lower than the safe level of 1, and Cr exhibited the highest risk value (0.249) for children, suggesting that the overall risk from exposure to multiple metals in dust is low. The carcinogenic risk for Cd and Cr was all below the acceptable level (< 10⁻⁶).

     

上海城市公园灰尘重金属污染及其潜在生态风险评价

通过对上海城市公园灰尘重金属含量的调查,发现上海城市公园灰尘重金属Pb、Zn、Cu、Cr、Cd和Ni含量的平均值分别为416.63 mg/kg、906.29 mg/kg2、35.89 mg/kg1、62.59 mg/kg1、.58 mg/kg和92.19 mg/kg,同上海市土壤环境背景值相比,均处于较高的积累水平。公园灰尘重金属空间上的分布特征表现为:内外环线之间公园灰尘各重金属元素含量平均值均高于内环线内公园;通过分析判定公园灰尘中较高的重金属含量可能主要源于交通和工业造成的污染。运用潜在生态危害指数法来评价上海城市公园灰尘重金属污染状况,发现单种重金属造成的潜在生态危害表现为:Cd>Pb>Cu>Ni>Zn>Cr;公园灰尘6种重金属潜在生态危害达到一个相当高的水平,在所调查的公园中,63.6%的公园灰尘重金属生态危害达到极高水平,29.5%的公园达到高水平,6.8%的公园处于较高水平。     

天津城市道路灰尘重金属污染特征

以天津城市道路灰尘重金属为研究对象,按照环线分布将天津市中心城区划分为内环以内、内环-中环、中环以外3个区域,总共设置93个采样点。对表层灰尘进行采样收集,预处理后测定样品的理化性质,采用原子吸收光谱仪测定道路灰尘中重金属Cd、Cr、Cu、Ni和Pb的含量,进而分析天津市道路灰尘重金属的含量水平,运用ArcGIS软件中的地统计分析方法内插得出其空间分布特征,通过Pearson相关分析和主成分分析判析重金属来源。研究结果表明：道路灰尘颗粒粒径表现为双峰,主峰对应粒径较小,且为非正态分布,大量小粒径颗粒的存在使重金属含量增高;市区和各环区有机质变异系数较大,道路灰尘中有机质的空间分布差异较大,因而人为因素影响广泛;市区道路灰尘中重金属 Cd、Cr、Cu、Ni 和 Pb的平均含量依次为0.99、121.41、100.62、43.35和61.48 mg·kg-1,分别为天津土壤环境背景值的11.00倍、1.44倍、3.49倍、1.30倍和2.93倍;Cd、Cr和Cu的空间分布差异较大,Ni和Pb的空间分布差异较小;Pearson相关分析表明Pb-有机质（P＜0.05）, Cu-Ni（P＜0.01）和Cr-Cu（P＜0.05）之间存在显著正相关关系,主成分分析人为因素的积累贡献率为33.050%,自然因素的积累贡献率为57.315%,因此得出重金属受人为因素影响较大,交通尾气排放和工业污染为天津道路灰尘重金属污染的重要来源,且以多因子复合影响为主。     

Investigating into composition,distribution, sources and health risk of phthalic acid esters in street dust of Xi’an City,Northwest China

Phthalic acid esters (PAEs) are widely used as plasticizers and in consumer products, which may enter the environment and present risks to human health. U.S. EPA classifies six PAEs as priority pollutants, which could be accumulated in street dust at the interface of atmosphere, biosphere and geosphere. This study collected a total of 58 street dust samples from Xi’an City in Northwest China and analyzed for concentrations of the priority PAEs. Composition, distribution, sources and health risk of the PAEs were further examined. All the priority PAEs were detected in the street dust. The concentrations of individual PAEs varied between not detected and 183.19 mg/kg. The sum of the 6 priority PAEs (∑6PAEs) ranged from 0.87 to 250.30 mg/kg with a mean of 40.48 mg/kg. The most abundant PAEs in the street dust were di-n-butyl phthalate and di (2-ethylhexyl) phthalate (DEHP). Higher concentrations of ∑6PAEs in the street dust were found in the south and west parts of Xi’an City as well as its urban center, which were possibly attributed to the prevailing northerly Asian winter monsoon. The PAEs in the street dust originated mainly from wide application of plasticizers as well as cosmetics and personal care products. The main pathways of human exposure to PAEs in the street dust were ingestion and dermal adsorption of dust particles. The non-cancer risk of human exposure to PAEs in the street dust was relatively low, while the risk to children was higher than that to adults. The cancer risk of human exposure to DEHP in the street dust was lower than the standard limit value of 10^?6.     

Human health risk from Pb in urban street dust in northern UK cities

The presence of Pb in the environment can cause significant health problems. These issues are exasperated when the lead is in a more amenable form for potential ingestion. This study investigates the potential human health risk from Pb in urban street dusts. The lead levels in urban street dust in major city centres in northern UK have been compared to levels determined in 35 cities around the world. With a few exceptions, it was noted that the mean Pb levels in this study exceeded those found in other cities worldwide. Samples (n = 15) of urban street dust were collected across five city centres, and specifically in areas in which pedestrians are likely to concentrate, as well as near historical buildings. Typical total lead concentrations across all sampling sites ranged from 306 to 558 mg/kg. The human health risk was assessed using oral bioaccessibility testing of the urban street dust. The mean oral bioaccessibility data, irrespective of site and sample location, were in the range 43 ± 9 %. The total and bioaccessible concentrations of lead were compared to the estimated tolerable daily intake (TDI_oral) values based on unintentional soil/dust consumption. It is noted, in all cases, that the maximum estimated lead daily intake exceeded the TDI_oral. An alternative approach for assessing the daily intake is proposed based on the actual measured air quality in selected cities on the same day as the sampled urban dust.     

Geochemistry and health risk assessment of arsenic exposure to street dust in the zinc smelting district, Northeast China

The aim of this study was to investigate arsenic (As) accumulation in street dust and health risk of population. The investigation concentrated on: a. pollution levels of As in street dust; b. spatial distribution of As in street dust; c. physicochemical properties analysis of street dust; and d. assessment of population health risk due to As exposure to street dust. As concentration in street dust ranged from 3.33 to 185.1?mg?kg^?1, with a mean of 33.10?mg?kg^?1, which was higher than the background value of Liaoning soil. As contamination level of the area closing to Huludao Zinc Plant (HZP) was highest. Spatial variation showed that the pollution center was close to HZP, formed radial distribution pattern and extended to the northeast and southwest of HZP. The pH and organic matter of street dust were both higher than the background values of soil in Liaoning. There was significantly negative correlation between As concentration and the pH. The mass percentages of particles 180?C100,?<100?C75,?<75?C63, and?<63???m were 29.8, 3.7, 21.3, and 4.2?%, respectively. The highest of As concentration was found in the smallest particle size (<63???m). As loadings in the particles of grain size 180?C100 and?<75?C63???m were higher than other particle fractions. Results of the risk assessment indicated that the highest risk was associated with the ingestion of street dust particles. Health risk for different use scenarios to human decreased in the order of HZP?>?Industrial district?>?School?>?Commercial center?>?Residential area. Around HZP, Hazard Index (HI) for children and cancer risk of As by street dust exposure exceeded the acceptable values. It indicated that there was a potential adverse effect on children health by As exposure to the street dust of Huludao.     

Spatial distribution and human health risk assessment of mercury in street dust resulting from various land-use in Ahvaz,Iran

Mercury as a toxic element and its associated health hazard has been an important topic of research for urban pollution for many years. In this paper, the spatial distribution, pollution assessment, and health risk associated with Hg in roadside dust 96 street dust samples, representing differing land-uses, have been investigated. Land-uses included residential areas (RA), industrial areas (IA), public gardens (PG), roadside areas (RS), and suburban areas (SA) in the city of Ahvaz, Iran were investigated. Compared with other cities, the concentration of Hg in Ahvaz was considerably higher with a mean value of 2.53 mg kg^?1, ranging from 0.02 to 8.75 mg kg^?1. Residential areas exhibited higher Hg in street dust than other areas, as demonstrated by spatial mapping illustrating hot spots associated with old urban areas with high residential density, high volume traffic of roadside areas, and industrial districts: including oil-drilling activities, steel smelting-related industries, and small industrial towns around Ahvaz. However, Hg concentrations in street dust near to the public gardens (PG) and suburban areas (SA) were not at elevated levels compared other land-uses investigated in this study. A health risk assessment model of non-carcinogenic effects was evaluated for both children and adults. The HQ values also revealed that the main exposures route for children and adults decreased as follows: vapour > ingestion > dermal contact > inhalation. The hazard index (HI) in each area is less than the safe level (HI ≤ 1) for children and adults, but higher for children. The HI value decreases as the following order: RS > IA > RA > SA > PG, which indicates potentially serious health hazards for children in the study areas.     

Influence of industry on the geochemical urban environment of Mieres (Spain) and associated health risk

This study is concerned with the elemental composition of soils and street dust collected in an historical industrial city of approximately 27 000 inhabitants, where old Hg mining and metallurgical activities strongly affected the load of heavy metals in the urban environment. For the purpose of the study, representative samples of soils and street dust were collected at different locations in the whole urban area (3 km²). Elevated mean concentrations of As in soils and street dust (69 and 135 g g^–1, respectively), and Hg (3.07 and 4.24 g g^–1, respectively), compared to background levels and to those found in other cities, reflect the anomalous geochemical nature of these materials and the strong influence exerted by the old mining sites.     

Characterization,heavy metal content and health risk assessment of urban road dusts from the historic center of the city of Thessaloniki,Greece

In the present study, an investigation of the mineralogy and morphology, the heavy metal content and the health risk of urban road dusts from the second largest city of Greece was conducted. For this reason road dust samples from selected sites within the city core area were collected. No differences were observed in the mineralogy of road dusts coming from different sampling sites, and they were mainly consisted of quartz and calcite, while an elevated amorphous content was detected. Morphologically road dusts presented Ca-rich, Fe-rich and silicates particles with various shapes and sizes. The mean concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn in road dust were 1.76, 104.9, 662.3, 336.4, 89.43, 209 and 452.8 μg g^?1, respectively. A series of spatial distribution patterns revealed that the hotspot areas were tended to associate with major road junctions and regions with high traffic. Combination of pollution indexes and statistical analyses (correlation analysis, cluster analysis and principal component analysis) revealed that road dusts have a severe influence by anthropogenic activities. In attempt to identify the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Cr, Cu, Fe and Zn mainly originated from tire/break wear and vehicle abrasions, while Cd, Mn and Pb were mainly related to fuel/oil leakage from automobiles along with oil lubricants and vehicle abrasion. Hazard quotient values for children based on total metal concentrations for the road dust ingestion route were lower than safe level (=1). However, the fact that the Hazard Index value for Pb (0.459) which is a particularly toxic metal, was close to safe level, renders essential further investigation in order to provide more reliable characterizations of potential health risks.     

Sequentielle Schwermetallextraktion aus Staubniederschlägen und Straßensedimenten

For the application of sequential extraction of heavy metals from samples that can only be obtained in amounts of a few milligrams (micro samples, e.g. airborne dust fallout), the method afterZeien &Brümmer (1989) was progressed. A down scale to 1∶100 was carried out and the accuracy of this method with variable sample amounts of about 20 mg and an extraction volume of 500 μl was proofed with standard soil samples. The influence of variable extraction ratios (ratio of sample amount and volume of extraction solvent) and the influence of intensive treatment of dust sampled by the Bergerhoff-method (VDI 2119/2, 1972) prior sequential extraction, was within the precision of measurement of our method. Thus, we showed that sequential extraction can be applied for the investigation of heavy metal mobilization in micro samples with variable sample amounts. A first application of our method for microsamples was carried out to investigate airborne dust fallout and street sediments at two urban sites where different heavy metal immission rates due to traffic influence occur. These investigations will be presented in part 2 (“Sequential extraction of heavy metals from urban dust”).     

Particle size distribution and pollutants in road-deposited sediments in different areas of Zhenjiang,China

An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 μm for TN).     

Assessment of human health risks from heavy metals in outdoor dust samples in a coal mining area

Jharia (India) a coal mining town has been affected by the consequences of mining and associated activities. Samples of outdoor fallen dust were collected at different locations of Jharia covering four different zones: commercial, petrol pump, high traffic, and residential areas. The dust samples were analysed for different trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn). The highest concentration of the elements in the dust samples are Mn (658 mg/kg), Zn (163.6 mg/kg), Cr (75.4 mg/kg), Pb (67.8 mg/kg), Ni (66 mg/kg), Cu (56.8 mg/kg), Co (16.9 mg/kg), As (4.1 mg/kg), and Cd (0.78 mg/kg). The concentration of selenium was below detection limit. Except Cd, contents of all the other elements in the dust samples were significantly lower in the residential area. High amount of Ni (145 mg/kg) and Pb (102 mg/kg) was observed in the high traffic and petrol pump areas, respectively. The exposure risk assessment strategies are helpful in predicting the potential health risk of the trace elements in the street dust. Selected receptors for risk assessment were infants, toddlers, children, teens, and adults. The calculated hazard quotient (HQ) for lifetime exposure was <1.0 for all the elements studied, indicating no risks from these elements for adults Among the receptors, toddlers were found to be more vulnerable, with HQ for Co, Cr, and Pb > 0.1. The finding predicts potential health risk to toddlers and children.     

典型工业城市大气降尘中重金属分布特征及其来源解析---以济南市为例

污染源解析是城市大气环境精准防治的重要基础。为探究典型工业城市大气降尘中重金属污染分布特征和污染源解析,本研究在济南市域内采集了35个大气降尘样品,分析了样品中重金属浓度及其空间分布特征,采用正定矩阵因子分析模型(Positive Matrix Factorization,PMF)解析降尘中重金属来源。研究结果表明,降尘中Mn、Fe、Co、Ni、Cu、Zn、As和Pb浓度平均值分别为501.4、29884.6、8.2、24.8、44.3、153.9、12.5、40.1 mg·kg^-1,其中Zn、Cu和Pb的地累积指数(Geoaccumulation Index,I_geo)分别为1.17、1.06和1.01,属于中度污染;钢铁冶炼较为发达的钢城区降尘中Mn、Fe、Co、Cu和As浓度显著高于其他区县,其浓度平均值分别为1172.4、73577.3、17.0、139.7、32.3 mg·kg^-1,而Zn和Pb在历下区、槐荫区等人口密集区域最高浓度可达351.5 mg·kg^-1和114.0 mg·kg^-1;PMF分析结果表明,济南市降尘重金属主要存在4个贡献源,分别为土壤源、工业源、交通源和混合源,贡献率分别为46.8%、26.6%、15.2%和11.4%。其中,重金属Co、Cu、Fe主要来自土壤源,Mn主要来自于土壤源和工业源的贡献,Ni主要来自于土壤源和混合源,交通源对降尘中Pb和Zn的贡献率较高,As则主要来自于工业源。本研究结果可为济南市大气环境精准防控政策的制定提供理论依据。     

城市地表颗粒物重金属分布特征及其影响因素分析

城市地表颗粒物作为重金属的重要载体,严重危害城市人群和水体,已成为城市环境的重要研究对象。阐述了对地表颗粒物重金属的空间、粒径、赋存形态等分布特征及其影响因素进行系统分析的意义。通过对国内不同城市不同功能区的重金属（主要为：Zn、Cu、Cd、Pb）数据进行对比分析,各功能区重金属污染情况为：Cu、Pb：工业区〉商业区〉交通区〉居民区〉休闲区;Zn：工业区〉交通区〉商业区〉居民区〉休闲区;Cd：交通区〉工业区〉商业区〉居民区〉休闲区,同时各功能区中Zn、Pb含量波动性较大。整体上国内工业区、交通区和商业区地表颗粒物重金属污染严重。与我国的土壤重金属背景值相比,4种金属中Cd污染程度最为严重。探讨了与国外部分城市地表颗粒重金属污染特征之间的差异,指出国内城市重金属含量均值整体上低于欧美发达城市,而国内一线城市重金属含量明显偏高。系统分析了颗粒物重金属的粒级效应,赋存形态以及生物有效性。综述了城市交通活动（主要为交通流量、车辆行驶速度、变速频率、车辆类型、道路特征等）、降雨冲刷事件、雨前干燥期、大气风力作用、和其他因素对地表颗粒物重金属分布特征的影响。某种程度上,道路车辆的行驶速度和变速对颗粒物重金属累积的影响作用大于交通流量。不同降雨事件和雨前干燥期对重金属分布特征影响的研究结论不一,但地表颗粒对大气PM2.5重金属贡献较大。今后应在以下方面进一步加强对城市地表颗粒物重金属的研究：建立颗粒物粒径划分标准;加强重金属在降雨冲刷过程变化规律的分析;探讨地表颗粒物与大气颗粒物重金属转换关系;还应开展中小型城市,城乡结合部（城中村）地表颗粒物重金属污染特性研究。     

Seasonal Variations and Chemical Forms of Heavy Metals in Soils and Dusts from the Satellite Cities of Seoul, Korea

This research investigated heavy metal pollution of soils and dusts in two representative satellite cities of Seoul, Korea and studied the seasonal variations in metal concentrations through the rainy season and the chemical forms of metals using a sequential extraction analysis. The metal dispersion pattern was illustrated to match with urban structure. Soil and dust samples were collected from the cities of Uijeongbu and Koyang, which are the northern and northwestern satellite cities of Seoul (the capital), before and after rainy season. Concentrations of Cu, Pb and Zn were higher than those of the world averages for soils, and their levels decreased after rain, particularly in highly contaminated samples. Relatively high pH values were found in roadside soils, but no seasonal variation was found after the rainy season. The three metals (Cu, Pb and Zn) in soils and dusts were associated with various chemical fractions of soils and dusts as distinguished by the sequential extraction scheme, and a strong similarity of metal association between soils and dusts was found, which indicates that airborne dust may be a principle source of soil contamination. Copper is uniformly distributed, and Pb is largely associated with the reducible phase. There is an appreciable proportion of total Zn in the exchangeable/water-acid soluble fraction. After the rainy season, the most soluble fractions in soils and dusts were leached away. In terms of mobility and bioavailability of metals in soils and dusts, the order Zn >> Cu > Pb is suggested. Geographical variations of total metals corresponded well with urbanised areas of cities, especially the industrial complex and major motorways.     

淮南市城区地表灰尘重金属分布特征及生态风险评价

城市地表灰尘中重金属会对人体健康和生态环境产生危害,为研究城市中不同功能区地表灰尘重金属的含量和潜在生态危害水平,以典型煤炭资源型城市淮南市的地表灰尘为研究对象,采集工业区、商业区、交通区、文教区、居住区和公园绿地等6种功能用地共40个点位的地表灰尘。采用电感耦合等离子体发射光谱（ICP-OES）和DMA-80直接测汞仪测定Zn、Pb、Cu、Cr、Cd、Ni、Co、V、Hg的含量,分析其在不同功能区地表灰尘中的分布特征、相关性及可能的来源;并应用潜在生态危害指数法对重金属在不同功能区的潜在生态危害进行评价。结果表明：1）淮南市地表灰尘中 Zn、Pb、Cu、Cr、Cd、Ni、Co、V、Hg的平均质量分数分别是202.59、74.63、62.74、110.69、0.57、35.82、12.18、50.95和0.105 mg·kg-1,其中Zn、Pb、Cu、Cr、Cd、Ni、Hg的平均含量分别是淮南市土壤背景值的3.47、3.17、2.04、1.21、9.50、1.12、2.56倍,是中国土壤背景值的2.73、2.87、2.78、1.81、5.88、1.33、1.62倍。2）9种重金属中,Zn和V的含量在不同功能区分布相对均匀,其他重金属在不同功能区含量均表现出较明显的空间异质性。3）不同功能区中,Zn、Pb、Cu、Ni、Co、V、Hg的平均含量在工业区最高,Cr 和 Cd 的平均含量在交通区最高。4）不同重金属的相关性表明,Zn、Pb、Cu、Cd、Ni 等5种元素有同一来源,Co 和 V 有同一来源。5）单项潜在生态危害系数大小为 Cd〉Hg〉〉Pb〉Cu〉Ni〉Co〉Zn〉Cr〉V。不同功能区9种重金属复合生态危害均处于强生态危害水平（300≤RI〈600）,其中工业区和交通区潜在生态危害水平最高。     

Spatial distribution and risk assessment of soil heavy metal contamination along roadsides of the northwestern Sichuan Plateau,China北大核心CSCD

Traffic activities in roadways are the major source of heavy metal contamination on the northwestern Sichuan Plateau, China. To characterize the spatial pattern of heavy metal distribution, we collected soil samples and measured the concentrations of five heavy metals (Cd, Cu, Ni, Pb, and Zn) from nine sites in Hongyuan County, Sichuan Province, including three transects that reflected typical gradients of traffic density. Each transect consisted of three levels of traffic density sites. We calculated single pollution index, Nemerow multi-factor index, and potential ecological risk index, to assess the ecological risk of the heavy metal contamination. Results showed that the soils were contaminated by Cd and Zn, with higher concentrations than that of the natural soil background values in all sampling sites. Moreover, Cd and Zn concentrations increased with increasing traffic density, suggesting that traffic activities were potentially responsible for the metal contaminations. The single pollution index indicated that the study sites were heavily contaminated by Cd and slightly polluted by Ni, Pb, and Zn, and the Nemerow multi-factor and potential ecological risk indexes indicated moderate potential ecological risks at the study sites. Specifically, the sites with high traffic density were moderately contaminated and the sites with low traffic density were mildly contaminated. In general, Cd and Zn were highly accumulated in soils of the study region; therefore focus should be on the high ecological hazard associated with soil heavy metal contamination, even in undeveloped regions. © 2018 Science Press. All rights reserved.