Heavy metal contamination of urban soils and dusts in Guangzhou, South China

The heavy metal concentrations of soil and dust samples from roadside, residential areas, parks, campus sport grounds, and commercial sites were studied in Guangzhou, South China. Heavy metals in samples were determined by inductively coupled plasma atomic emission spectrophotometer following acidic digestion with HClO₄ + HF + HNO₃. High concentrations, especially of Cd, Pb, and Zn, were found with mean concentrations of Cd, Cr, Cu, Ni, Pb, and Zn in the urban dusts being 4.22?±?1.21, 62.2?±?27.1, 116?±?30, 31.9?±?12.6, 72.6?±?17.9, and 504?±?191 mg/kg dry weight, respectively. The respective levels in urban soils (0.23?±?0.19, 22.4?±?13.8, 41.6?±?29.4, 11.1?±?5.3, 65.4?±?40.2, and 277?±?214 mg/kg dry weight, respectively), were significantly lower. The integrated pollution index of six metals varied from 0.25 to 3.4 and from 2.5 to 8.4 in urban soils and dusts, respectively, with 61 % of urban soil samples being classified as moderately to highly polluted and all dust samples being classified as highly polluted. The statistical analysis results for the urban dust showed good agreement between principal component analysis and cluster analysis, but distinctly different elemental associations and clustering patterns were observed among heavy metals in the urban soils. The results of multivariate statistic analysis indicated that Cr and Ni concentrations were mainly of natural origin, while Cd, Cu, Pb, and Zn were derived from anthropogenic activities.     

百年一遇大旱后城区降雨径流中重金属与悬浮物相关性分析

为了探讨2009年入秋至2010年春,西南百年一遇大旱后城市降雨径流中重金属污染特性,对昆明市交通干道路面及路旁一处混凝土屋面的3次降雨径流进行了监测,研究了城区降雨径流中Cu、Zn、Cd、Pb、Fe、Mn、Cr的变化过程,分析了不同重金属之间、重金属与悬浮物(SS)之间的相关性。3次降雨径流中重金属质量浓度随降雨呈不同程度下降。大旱后的首次降雨径流重金属污染最严重,次日的降雨径流重金属污染最轻。降雨径流中各重金属均与SS在含量上明显相关,径流中的重金属主要以吸附在SS上的不溶态存在。屋面与路面径流中的大多数重金属具有良好的同源性。     

Heavy metal contents and magnetic susceptibility of soils along an urban–rural gradient in rapidly growing city of eastern China

The accumulation of heavy metals (Cd, Cr, Cu, Pb and Zn) and magnetic minerals in soils along an urban-rural gradient in the rapidly growing Hangzhou City, Eastern China, was measured. The analytical results indicated that heavy metal concentrations, magnetic susceptibility (chilf) and saturation isothermal remnant magnetization (SIRM) in soils decreased with increasing distance from the urban center. The significant relationships existed between heavy metal concentrations, chilf and SIRM and distance from the urban center. The soils in the urban areas were enriched with Cd, Cu, Pb and Zn. Elevated concentrations of heavy metals (especially Cd and Zn) in urban areas indicated the evidence for the accumulation of heavy metal contaminants from anthropogenic activities. Enhanced heavy metal concentrations and magnetic susceptibility were located in the uppermost soil horizons (0-10 cm), decreasing downwards to background values. The significant positive correlations between the Tomlinson Pollution Load Index (PLI) and magnetic susceptibility and SIRM were observed in polluted soil samples. Strong positive correlation indicated that magnetic screening/monitoring provided a fast and non-destructive tool, which can be effectively used as a proxy to detect environmental pollution in rapidly growing urbanization regions affected by anthropogenic activities.     

Contamination of Polish national parks with heavy metals

The paper presents results of screening analysis of all Polish national parks (23) contamination with Cd, Cu, Pb and Zn on the basis of a three-level characteristic of heavy metal presence in Norway spruce stands: accumulation on the needle surface, concentration of heavy metals in spruce needles and concentration of bioavailable heavy metals in the soil. Based on the obtained results, the classification of forest ecosystem hazard in national parks with heavy metals was made using synthetic indicators. It was found out that Babiogórski, Magurski, Ojcowski and Gorczański National Parks, located in the southern part of the country, were the most polluted with heavy metals. It is probably due to a higher industrial activity in this part of Poland and the transboundary transport of air pollutants. A little lower level of pollution was observed in Kampinoski National Park located in the middle of the country. The concentration of heavy metals found in needles from national parks does not seem to be harmful for the health status of the trees. Statistically significant correlation between all parameters, which was found for cadmium--the most mobile of the analysed elements--shows that this metal can be proposed as a marker to reflect present effect of industrial emission on forests.     

Environmental Quality Of Urban Parks And Open Spaces In Hong Kong

It is widely purported that urban parks and open spaces can improve the urban environment by cleansing the air and reducing the noise. However, such environmental functions can be constrained by the size and the location of urban parks in very dense cities. This study examines the air and acoustic environment and heavy metal contamination in Hong Kong urban parks and open spaces. Using a hybrid field measurement and computer simulation approach, the study has found that while the air quality in urban parks is better than that of the roadside, it is not significantly different from that of the ambient conditions. Noise levels in the urban parks are not significantly lower than those at the typical home environment in Hong Kong. Heavy metals in urban park dust are slightly lower than that found at the roadside and are broadly comparable to those found at typical homes and nursery schools. These findings lend support to the postulation that the capability of urban parks and open spaces in dense cities to improve the urban environment is rather limited and call for a re-examination of the role of urban parks in enhancing urban livability. The findings also have implications on how urban parks in dense cities should be designed and managed.     

Black carbon in urban topsoils of Xuzhou (China): environmental implication and magnetic proxy

Combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. However, little is understood about the environmental roles of black carbon in urban soils. This investigation represented the preliminary study to characterize black carbon (BC) concentrations and enrichment ratios in Xuzhou urban roadside topsoil. Data from 21 roadside topsoil samples showed that the median of BC concentrations is 21.8 mg/g, which is significantly higher than local background value that averages 3.8 mg/g. Hierarchical clustering analysis indicated that BC in Xuzhou urban roadside soils are mainly from the traffic emissions. The marked positive correlations between BC and the concentrations of heavy metals (Pb, Cu, Zn, Mo, and Sc; Pearson correlation coefficient, 0.623, 0.809, 0.846, 0.742 and 0.831, respectively) suggested that these heavy metals are likely to be strongly retained by BC present in roadside topsoil. The significant positive correlation between BC and specific magnetic susceptibility was also observed. Thus, the simple environmental magnetic method is potentially an efficient alternative technique for assessing BC concentration in roadside topsoil.     

Determination of Pb and Cd in road dusts over the period in which Pb was removed from petrol in the UK

It is commonly agreed that automobile exhaust has been the most important source of Pb pollution in urban areas, and that Cd may come from wear and tear of tyres. This study evaluates the fall in Pb concentrations in road dusts in Manchester as a consequence of the removal of Pb from petrol in January 2000. In the work presented here a slurry graphite furnace atomic absorption methodology for the determination of Pb and Cd in road dusts has been developed and is compared with an acid digestion method in terms of efficiency. The reproducibility and accuracy of the results obtained by acid digestion and the slurry method have been studied and a certified reference material CRM 038 was analysed to confirm the reliability of the proposed methods. Different factors were evaluated throughout this work including: (i) the effect of traffic density on Pb and Cd levels in road dust samples collected weekly during the period of May 1999 until September 2000; (ii) comparison between the Pb and Cd levels in a busy road and a residential street; (iii) the effect of distance from the source on Pb and Cd levels; The results of these experiments show a reduction in Pb levels over the sampling period. The relationship between road dust particle size and Pb and Cd concentration was also investigated in the 4-250 microns size range using the slurry method, showing that there is a relationship between metal concentration and particle size; the highest concentrations being for the smallest particle size.     

上海市浦东新区大气细颗粒物中重金属污染特征及来源解析

于2017年对浦东城区和郊区大气PM2.5中的重金属特征和来源进行了分析。结果表明,K、Fe、Na、Ca、Mg、Al等矿物元素为浦东新区PM2.5中含量最高的金属元素,其中K的年均值为297.3 ng/m^3。浦东城区的不同元素在季节变化上呈现较为不同的变化规律,郊区的金属元素值大部分呈现春季先逐月下降,在夏、秋季有起伏波动,在10月之后逐渐上升;沙尘+道路源+建筑扬尘、煤燃烧、工业排放、金属冶炼、船舶排放、海盐+垃圾焚烧+生物质燃烧为浦东城区PM2.5中重金属元素的6大类主要来源。其中沙尘+道路源+建筑扬尘对Ca的贡献率为82.7%,煤燃烧对As的贡献率为86.6%,工业排放对SO4^2-的贡献率达到65.9%,金属冶炼对Cr的贡献率为75.7%,船舶排放对V的贡献率为97.5%、海盐+垃圾焚烧+生物质燃烧对Cl^-的贡献率为93.0%。煤燃烧和金属冶炼主要来自于西部方向。船舶排放分布在长江口及其延伸带。浦东新区PM2.5中重金属元素的质量浓度与本地源排放强度、外界传输和大气扩散条件均有密切关系。     

Concentrations and bioaccessibility of metals in vegetation and dust near a mining haul road, Cape Krusenstern National Monument, Alaska

Vegetation, sub-surface peat, and road dust were sampled near the Delong Mountain Transportation System (DMTS) haul road in northwest Alaska in 2005-2006 to document aluminum, barium, cadmium, lead, and zinc concentrations, and to evaluate bioaccessibility of these metals. The DMTS haul road is the transport corridor between Red Dog Mine (a large-scale, lead-zinc mine and mill) and the coastal shipping port, and it traverses National Park Service lands. Compared to reference locations, total metal concentrations in four types of vegetation (birch, cranberry, and willow leaves, and cotton grass blades/stalks) collected 25 m from the haul road were enriched on average by factors of 3.5 for zinc, 8.0 for barium, 20 for cadmium, and 150 for lead. Triple rinsing of vegetation with a water/methanol mixture reduced metals concentrations by at most 50%, and cadmium and zinc concentrations were least affected by rinsing. Cadmium and zinc bioaccessibility was greater in vegetation (50% to 100%) than in dust (15% to 20%); whereas the opposite pattern was observed for lead bioaccessibility (<30% in vegetation; 50% in dust). Barium exhibited low-to-intermediate bioaccessibility in dust and vegetation (20% to 40%), whereas aluminum bioaccessibility was relatively low (<6%) in all sample types. Our reconnaissance-level study indicates that clean-up and improvements in lead/zinc concentrate transfer activities have been effective; however, as of 2006, metal dispersion from past and/or present releases of fugitive dusts along the DMTS road still may have been contributing to elevated metals in surface vegetation. Vegetation was most enriched in lead, but because bioaccessibility of cadmium was greater, any potential risks to animals that forage near the haul road might be equally important for both of these metals.     

环境磁学在城市地表灰尘重金属污染研究中的应用

随着环境问题日渐突出,地表灰尘重金属污染日益成为研究热点。单纯采用化学方法监测重金属污染具有一定局限性,环境磁学方法以其简便、快捷、经济且无害化的特点在城市重金属污染研究中广为应用。通过文献调研,综述环境磁学在城市地表灰尘重金属污染研究中的应用与研究进展,阐明重金属的主要来源,简述环境磁学的诸多参数,分析磁学参数与重金属的关系,并通过对比不同的磁学分析方法,探讨环境磁学方法在城市地表灰尘重金属污染研究中存在的问题及其发展趋势。     

A comparative study of noise pollution levels in some selected areas in Ilorin Metropolis, Nigeria

The noise pollution is a major problem for the quality of life in urban areas. This study was conducted to compare the noise pollution levels at busy roads/road junctions, passengers loading parks, commercial, industrial and residential areas in Ilorin metropolis. A total number of 47-locations were selected within the metropolis. Statistical analysis shows significant difference (P < 0.05) in noise pollution levels between industrial areas and low density residential areas, industrial areas and high density areas, industrial areas and passengers loading parks, industrial areas and commercial areas, busy roads/road junctions and low density areas, passengers loading parks and commercial areas and commercial areas and low density areas. There is no significant difference (P > 0.05) in noise pollution levels between industrial areas and busy roads/road junctions, busy roads/road junctions and high density areas, busy roads/road junctions and passengers loading parks, busy roads/road junctions and commercial areas, passengers loading parks and high density areas, passengers loading parks and commercial areas and commercial areas and high density areas. The results show that Industrial areas have the highest noise pollution levels (110.2 dB(A)) followed by busy roads/Road junctions (91.5 dB(A)), Passengers loading parks (87.8 dB(A)) and Commercial areas (84.4 dB(A)). The noise pollution levels in Ilorin metropolis exceeded the recommended level by WHO at 34 of 47 measuring points. It can be concluded that the city is environmentally noise polluted and road traffic and industrial machineries are the major sources of it. Noting the noise emission standards, technical control measures, planning and promoting the citizens awareness about the high noise risk may help to relieve the noise problem in the metropolis.     

成都市地表灰尘重金属污染分布特征及健康风险评价

对成都市中心城区娱乐区、居民区、商业区和城市广场等日常活动区域代表点的地表灰尘中的重金属进行监测,分析其污染分布特征,并应用美国EPA人体暴露风险评价方法对地表灰尘进行了健康风险评价。结果表明,研究区域地表灰尘重金属污染较为严重,Pb、Zn、Cu、Ni、Cr、Cd的平均含量分别为成都市土壤背景值的1.18~77.57倍,其中Cd的富集因子大于10,污染极强且富集在颗粒物中。暴露模型计算表明,重金属慢性每日平均暴露量为手-口摄入量皮肤吸收量吸入空气量,经手-口接触行为是人体地表灰尘暴露风险的主要途径。儿童重金属非致癌风险CrPbCdCuZnNi,成人重金属非致癌风险PbCrCdCuZnNi,且均小于非致癌风险阈值1,不会对城市人群造成明显伤害。重金属致癌风险CrCdNi,均低于致癌风险阈值,表明不具有致癌风险,但潜在生态危害值得重视。     

北京市建筑施工裸地的空间分布及扬尘效应

北京市作为中国典型的快速城市化大城市之一,大规模的城市建设使得城市内部存在大量的建筑施工裸地,工地扬尘效应造成了严重的大气颗粒物污染。以北京市平原区为研究区,首先利用高分辨率卫星数据反演了建筑施工裸地的空间分布格局,在此基础上,结合建筑施工裸地的扬尘排放因子,在空间上定量分析建筑施工裸地的扬尘效应。结果显示,2012年全市平原区建筑施工裸地总面积为140.77 km2,主要分布在城市核心区向外拓展的城乡过渡带。建筑施工裸地的扬尘效应分析中发现北京市平原区建筑施工裸地中TSP、PM10和PM2.5的排放量分别是31.53、16.66、9.16万吨,并且这些污染物的排放量在城市发展新区与功能拓展区中较高,生态涵养发展区较小。以北京市的建筑施工裸地为例,示范了以遥感为技术手段结合污染排放因子的城市内部典型面源污染的监测和污染排放定量化,为今后面源污染的快速准确监测开辟了新的研究思路。     

Evaluation of Noise Pollution in Urban Parks

The present study provides an evaluation of noise pollution in six Urban Parks located in the city of Curitiba, Brazil. Equivalent noise levels (L _eq) were measured in 303 points (each point measured during 3 min) spread throughout the Parks. Measured values were confronted with local legislation (Law 10625) allowed limits, and the Parks were thus classified as “acoustically polluted or unpolluted”. Measured values were also evaluated according to international legislation: Decree no. 12 of the City Council of Rome, DIN 18005 for German cities, the World Health Organization, and the United States Environmental Protection Agency. Urban parks in the downtown area of Curitiba, surrounded by roads of heavy traffic and in the midst of intense commercial activities, do not satisfy any of the standards used. The most noise-polluted parks in Curitiba were the Public Walk Park and the Botanical Garden Park, with measured L _eq of 64.8 dB(A) and 67 dB(A).     

Heavy metal pollution across sites affecting the intestinal helminth communities of the Egyptian lizard, Chalcides ocellatus (Forskal, 1775)

This study aimed to investigate the possible effects of heavy metal pollution across sites and some biological factors on helminth communities infecting the lizard, Chalcides ocellatus. The possibility of heavy metal accumulation by such helminths was also investigated. A total of 202 C. ocellatus were collected from three different sites (industrial, rural, and urban systems) in Ismailia governorate, Egypt, during summer 2009. The lizards were classified according to their sex and size and were examined for the intestinal helminths. Heavy metal levels were detected in the intestinal tissue of the lizards and the recovered helminths. Species richness was 6, 5, and 3 in rural, urban, and industrial systems, respectively. Significant site variations regarding infection prevalence, intensity, and abundance were encountered at different levels. Some noticeable effects of the host size were found. The significant differences found between the metal levels of the intestinal tissues and the recovered helminths and the other relations found in this study may be indications for a possible metals accumulation capacity by helminths. The cestode Oochoristica tuberculata could be a promising biomonitor for Cu and Pb, while the intestinal nematodes were less sensitive to the pollution. Differences in the accumulation capacity may be attributed to the intensity of infection, parasite species, and metal. The observed patterns of distribution and occurrence of helminths and the metals accumulation capacity reflect the need for more studies since this study proposes the model intestinal helminth/C. ocellatus as another promising bioindication system in the terrestrial habitat, especially in areas where the lizard C. ocellatus are available.     

燃煤电厂周边大气重金属污染特征及来源解析

为探究燃煤电厂周边大气环境中重金属的污染特征与来源,对广东某山区燃煤电厂周边地区环境和污染源的重金属进行测定,分析其污染特征,采用因子分析法和Pb同位素示踪法对环境中的重金属进行来源解析。结果表明,研究区域室内积尘中重金属浓度水平明显高于土壤重金属,污染空间分布与当地气象条件相关。环境空气TSP中重金属主要来自2个污染源,Cd、Pb、As主要来自电厂燃煤,Ca、Mn、Al、Mg主要来自土壤扬尘。TSP、降尘、积尘样品所含的Pb均与电厂采集的煤、炉渣、粉煤灰样品所含的Pb具有同源性,与其他污染源同源性不明显,说明研究区域大气中Pb污染主要来自电厂燃烧所排放的烟尘,其他污染源影响不大。     

Contamination assessment of arsenic and heavy metals in a typical abandoned estuary wetland—a case study of the Yellow River Delta Natural Reserve

Coastal and estuarine areas are often polluted by heavy metals that result from industrial production and agricultural activities. In this study, we investigated the concentration trait and vertical pattern of trace elements, such as As, Cd, Ni, Zn, Pb, Cu, and Cr, and the relationship between those trace elements and the soil properties in coastal wetlands using 28 profiles that were surveyed across the Diaokouhe Nature Reserve (DKHNR). The goal of this study is to investigate profile distribution characteristics of heavy metals in different wetland types and their variations with the soil depth to assess heavy metal pollution using pollution indices and to identify the pollution sources using multivariate analysis and sediment quality guidelines. Principal component analysis, cluster analysis, and pollution level indices were applied to evaluate the contamination conditions due to wetland degradation. The findings indicated that the concentration of trace elements decreased with the soil depth, while Cd increases with soil depth. The As concentrations in reed swamps and Suaeda heteroptera surface layers were slightly higher than those in other land use types. All six heavy metals, i.e., Ni, Cu, As, Zn, Cr, and Pb, were strongly associated with PC1 (positive loading) and could reflect the contribution of natural geological sources of metals into the coastal sediments. PC2 is highly associated with Cd and could represent anthropogenic sources of metal pollution. Most of the heavy metals exhibited significant positive correlations with total concentrations; however, no significant correlations were observed between them and the soil salt and soil organic carbon. Soil organic carbon exhibited a positive linear relationship with Cu, Pb, and Zn in the first soil layer (0–20 cm); As, Cr, Cu, Ni, Pb, and Zn in the second layer (20–40 cm); and As, Cr, Cu, Ni, Pb, and Zn in the third layer (40–60 cm). Soil organic carbon exhibited only a negative correlation with Cd (P?I _geo values), which averaged less than 0 in the three soil layers, this finding indicates that the soils have remained unpolluted by these heavy metals. The mean concentrations of these trace elements were lower than Class I criteria. The degradation wetland restoration suggestions have also been provided in such a way as to restore the reserved flow path of the Yellow River. The results that are associated with trace element contamination would be helpful in providing scientific directions to restore wetlands across the world.     

Using of high-resolution topsoil magnetic screening for assessment of dust deposition: comparison of forest and arable soil datasets

Magnetic susceptibility (κ) is an easily detectable geophysical parameter that can be used as a proxy or semi-quantitative tracer of atmospheric industrial and urban dusts deposited in topsoil. An enhanced κ value of topsoil is in many cases also associated with high concentrations of soil pollutants (mostly heavy metals). High-resolution magnetic screening of topsoil in areas of high pollution influx is a useful tool for detection of pollution “hot spots”. General and regional screening maps with a grid density of 10 or 5 km have been performed on the basis of forest topsoil measurement only. The purpose of this study was to perform high-resolution magnetic screening with different grid densities in both forested and agricultural areas (arable land). Our large study area (ca. 200 km²) was located in a relatively more polluted region of the central part of Upper Silesia, and a second (small) one (ca. 100 m²) was located in the western part of Upper Silesia, with considerably lower influx of pollution. In the framework of this study, we applied a statistical comparison of data obtained in forested areas and on arable land. The arable soil showed statistically significantly lower κ values, the result of “physical dilution” of the arable layer caused by annual ploughing. Thus arable soils must be avoided during high-resolution field measurement. From semivariograms, it was clear that the spatial correlations in forest topsoil are much stronger than in arable soil, which suggests that a denser measurement grid is required in forested areas.     

Roadside Rhododendron pulchrum leaves as bioindicators of heavy metal pollution in traffic areas of Okayama, Japan

The leaves of roadside Rhododendron pulchrum Sweet were examined as a bioindicator of traffic-related heavy metal pollution in Okayama. Total contents of heavy metals in roadside soil and the R. pulchrum leaves were determined. Results of correlation analyses showed significant correlations among Pb, Ni, and Zn contents of roadside soil and leaf samples. These results suggest that R. pulchrum is a useful bioindicator of heavy metal pollution in traffic areas. To identify traffic-related heavy metal pollution sources, traffic-related materials such as tires, asphalt pavement, and road paint were collected and analyzed. The results of analyses of our data show that Zn is emitted mainly from the abrasion of tires; Cr is emitted mainly from wear of the asphalt pavement. Furthermore, the respective lead isotope ratios in R. pulchrum leaves, soil, roadside dust, and traffic-related materials were measured using inductively coupled plasma mass spectrometry. The isotopic compositions of lead in R. pulchrum leaves were 207Pb/206Pb = 0.861-0.871 and 208Pb/206Pb = 2.093-2.127, which agrees well with ratios in automobile wheel balance weights, suggesting that lead-containing products associated with automobiles, such as wheel balance weights, contribute to traffic-related lead pollution.     

Similarities and differences of metal distributions in the tissues of molluscs by using multivariate analyses

Multivariate analysis including correlation, multiple stepwise linear regression, and cluster analyses were applied to investigate the heavy metal concentrations (Cd, Cu, Fe, Ni, Pb, and Zn) in the different parts of bivalves and gastropods. It was also aimed to distinguish statistically the differences between the marine bivalves and the gastropods with regards to the accumulation of heavy metals in the different tissues. The different parts of four species of bivalves and four species of gastropods were obtained and analyzed for heavy metals. The multivariate analyses were then applied on the data. From the multivariate analyses conducted, there were correlations found between the soft tissues of bivalves and gastropods, but none was found between the shells and the soft tissues of most of the molluscs (except for Cerithidea obtusa and Puglina cochlidium). The significant correlations (P < 0.05) found between the soft tissues were further complemented by the multiple stepwise linear regressions where heavy metals in the total soft tissues were influenced by the accumulation in the different types of soft tissues. The present study found that the distributions of heavy metals in the different parts of molluscs were related to their feeding habits and living habitats. The statistical approaches proposed in this study are recommended for use in biomonitoring studies, since multivariate analyses can reduce the cost and time involved in identifying an effective tissue to monitor the heavy metal(s) bioavailability and contamination in tropical coastal waters.