Heavy metals in urban soils: a case study from the city of Palermo (Sicily), Italy

Concentrations of V, Mn, Cd, Zn, Ni, Cr, Co, Cu, Pb, Hg and Sb were measured on 70 topsoil samples collected from green areas and parks in the city of Palermo (Sicily) in order to: (1) assess the distribution of these heavy metals in the urban environment; (2) discriminate natural and anthropic contributions; and (3) identify possible sources of pollution. Mineralogy, physico-chemical parameters, and major element contents of the topsoils were determined to highlight the influence of 'natural' features on the heavy metal concentrations and their distribution. Medians of Pb, Zn, Cu and Hg concentrations of the investigated urban soils are 202, 138, 63 and 0.68 mgkg(-1), respectively. These values are higher, in some case by different orders of size, than those of unpolluted soils in Sicily that average 44, 122, 34 and 0.07 mg kg(-1). An ensemble of basic and multivariate statistical analyses (cluster analysis and principal component analysis) was performed to reduce the multidimensional space of variables and samples, thus defining two sets of heavy metals as tracers of natural and anthropic influences. Results demonstrate that Pb, Zn, Cu, Sb and Hg can be inferred to be tracers of anthropic pollution, whereas Mn, Ni, Co, Cr, V and Cd were interpreted to be mainly inherited from parent materials. Maps of pollutant distribution were constructed for the whole urban area pointing to vehicle traffic as the main source of diffuse pollution and also showing the contribution of point sources of pollution to urban topsoils.     

Spatial variation of urban soil geochemistry in a roadside sports ground in Galway, Ireland

Characterization of spatial variation of urban soil geochemistry especially heavy metal pollution is essential for a better understanding of pollution sources and potential risks. A total of 294 surface soil samples were collected from a roadside sports ground in Galway, Ireland, and were analysed by ICP-OES for 23 chemical elements (Al, Ca, Ce, Co, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, P, Pb, S, Sc, Sr, Th, Ti, V, Y and Zn). Strong variations in soil geochemistry were observed and most elements, with the exception of Cu, Pb, P, S and Zn, showed multi-modal features, indicating the existence of mixed populations which proved difficult to separate. To evaluate the pollution level of the study area, the pollution index (PI) values were calculated based on a comparison with the Dutch target and intervention values. None of the concentrations of metal pollutants exceeded their intervention values, indicating the absence of serious contaminated soil, and the ratios to target values were therefore employed to produce the hazard maps. The spatial distribution and hazard maps for Cu, Pb and Zn indicated relatively high levels of pollution along the southern roadside extending almost 30 m into the sports ground, revealing the strong influence of pollution from local traffic. However, heavy metal pollution was alleviated along the eastern roadside of the study area by the presence of a belt of shrubs. Therefore, in order to prevent further contamination from traffic emissions, the planting of hedging or erection of low walls should be considered as shields against traffic pollution for roadside parks. The results in this study are useful for management practices in sports and parks in urban areas.     

Polycyclic Aromatic Hydrocarbons (PAHs) in urban topsoils: Concentration and source analysis in Xuzhou,China

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants in urban environments and are considered as the priority pollutants by the US Environmental Protection Agency (EPA). In this study, surface soils (0–10 cm) samples from 41 sampling sites in Xuzhou (China) were collected and analysed for 16 EPA priority polycyclic aromatic hydrocarbons via gas chromatograph/mass spectrometry (GC-MS). Total PAHs concentrations were in the range of 526 to 8612 ng/g with a mean of 2468 ng/g. Total PAHs concentrations were compared to guideline and results showed that nearly all urban soils in our study can be classified as heavily contaminated (>1000 ng/g). Carcinogenic PAHs were detected in relatively high concentrations and contributed 40.2% of the total PAHs in the urban soils. Multivariate statistical analysis including cluster analysis and factor analysis were performed and grouped the 16 PAHs under 2 clusters, which could indicate that the PAHs had different origins. The values of PAHs isomer indicated that vehicular emission might contribute to the soil PAHs in urban topsoils. The carcinogenic potency of PAH compounds was calculated and was found to be insignificant at the present level of emissions in Xuzhou.     

增长、结构和效率——兼评中国城市空间发展模式

研究表明,中国的城市空间发展存在六种缺少效率的典型形态,分别是：分散组团式发展,破碎化的土地开发、过度规模的土地开发,蛙跳式发展．空间随机式发展,过度的混合用途。为推动城市可持续的空间发展,应增强城市规划中经济．定量、模型等方面的分析;引进市场机制,充分发挥土地价值对城市空间发展的作用,实行灵活和多样的城市规划建设标准,实行灵活的土地利用功能分区等措施。     

上海外资制造业企业的空间分布特征

外商投资企业是上海工业经济发展的重要力量,外资制造业企业的空间分布对上海城市功能与结构的调整产生了很大影响。利用上海市1995年和2000年外资制造业企业的数据资料分析了企业空间分布的离散趋势、整体分布特征和结构性分布特征,在此基础上归纳出了三种区位模式,并对城市规划的编制和管理作出客观的评析。     

DNA damage and lipid peroxidation vs. protection responses in the gill of Dicentrarchus labrax L. from a contaminated coastal lagoon (Ria de Aveiro, Portugal)

The present research work aimed to investigate the damage vs. protection responses in gill of European sea bass (Dicentrarchus labrax) captured at a polluted coastal lagoon, Ria de Aveiro (Portugal), as a tool to evaluate the human impacts on environmental health. Damage was assessed as DNA strand breakage and lipid peroxidation (LPO) whereas protection was evaluated by measuring catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (GSHt), thiols and metallothioneins (MT). Fish were caught at five locations: Gafanha (GAF), Rio Novo do Príncipe (RIO), Laranjo (LAR) and Vagos (VAG) presenting each a different recognized source of contamination, and Torreira (TOR), assumed as reference site. Among the surveyed sites, gill damage was observed only at GAF, as measured by DNA integrity loss and LPO increase. An overall induction in enzymatic antioxidant protection was perceptible in fish from GAF and VAG, expressed as higher GPX, GR and GST activities. In addition, LAR fish showed elevated GST and CAT activities. Thiols content was higher in all study sites irrespective to the pollution spectrum, whereas GSHt increase was only observed at GAF and VAG. The highest MT level was detected in fish from VAG and the lowest level from RIO suggesting a low contamination degree on this particular site. Globally, the results expressed site-specific response patterns, signalling two critical areas - GAF and VAG. Additionally, a joint analysis (damage vs. protection) allowed the following ordering of surveyed sites according to the contamination degree and risk to fish health; GAF>VAG>LAR>RIO>TOR. D. labrax gill responses demonstrated their efficacy as early warning signals of the contaminants presence. Moreover, the adopted approach, considering simultaneously protection responses and damaging effects, also revealed its usefulness on the pollution extent assessment.     

秦皇岛山区至沿海一线土壤养分元素空间分布特征

通过对秦皇岛山区—平原—沿海一线土壤元素采样与化验分析,研究沿线土壤养分元素的空间分布特征。基于沿线105个采样点,分析了土壤养分的空间地球化学特征。结果表明：土壤养分综合等级在朱杖子乡以北为三等,双山子镇—大新寨插旗梁块段一等至三等均有分布,其他地段为四等。土壤养分综合指标林草地>农用地,养分综合指标山区生态用地>平原农业用地>沿海工业用地。本研究建立了秦皇岛山区至沿海的山区生态用地、山前农业用地、沿海工业用地3种不同土地利用类型的综合土壤地球化学剖面,可为秦皇岛地区农业绿色发展提供科学依据。     

High resolution thermo-radiative modeling of an urban fragment in Marseilles city center during the UBL-ESCOMPTE campaign

The thermodynamic exchanges of the old city center of Marseilles during a summer period are analyzed with the SOLENE thermo-radiative model, using measurements of the UBL-ESCOMPTE experimental campaign in June–July 2001. The selected scene is an actual fragment of the urban canopy composed of 4 streets at right angles, with various 19th century houses and yards. The SOLENE software’s ability to simulate the heat and radiation exchanges of this urban district with the atmosphere is first evaluated by comparing simulation outputs with surface temperatures of individual roof and façade elements measured by infrared radiation thermometers and with integrated fluxes measured on top of a neighboring meteorological mast. This model assessment is reinforced by a sensitivity study to the interior building temperature, a variable of possible influence which is usually not measured in studies at the scale of an urban fragment or district. The flux sensor position influence on the comparison is also studied by introducing a virtual sensor in the simulated scene. The software is further used to analyze the behavior of individual surface elements of the scene with various orientations during a typical summer diurnal cycle. The contributions of the different surface classes (roofs, façades, streets, yards) to the upward radiation and heat fluxes to the atmosphere are then detailed for several canopy morphologies (H/W).     

浅谈丘陵城市道路规划——以闽清县城为例

本文介绍了城市道路规划的基本要求及道路交通理论，在此基础上研究了丘陵城市道路的特点、主要影响因子及线形设计要点，并以闽清县为例，进行实证研究。通过对闽清县城市现状道路系统的详细分析，找出其问题症结所在，提出具体的解决方案，为丘陵城市道路规划提供了参考依据。     

Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain

Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO₂) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO₂ samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO₂ were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 µg m^− 3 respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO₂ occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO₂ exceeded the European limits at some of the monitored points.     

Analysis of composition, distribution and origin of hexachlorocyclohexane residues in agricultural soils from NW Spain

Concentrations of the isomers of the organochlorine pesticide hexachlorocyclohexane (HCH) were determined in 252 surface soil samples collected within a sampling network covering agricultural areas in Galicia (NW Spain). The concentration of total HCH (sum of α + β + γ + δ) ranged between 4 and 2305 ng g⁻¹ (dry weight), with the α-HCH and γ-HCH isomers predominating (< 1-1404 ng g⁻¹ and < 1-569 ng g⁻¹, respectively). The distribution of the pesticide residues was very heterogeneous, with the largest concentrations present in one of the studied areas (the province of A Coruña). The distribution of HCH was not found to be related to any soil property (organic matter, pH, clays, and metals). Multivariate statistical analysis of the data revealed that three populations of samples with a defined composition of HCH, can be related to the source of HCH: technical HCH (α/γ > 3), lindane (99% γ-HCH), or both. The existence of a third population consisting almost exclusively of α-HCH suggests that background contamination of anthropogenic origin dates from several decades ago. The detailed analysis of these populations enabled the possible temporal scale of the application of these pesticides to be deduced.     

Development of an urban health and wellbeing index for work precincts: A comparative study in Sydney,Australia

Work precincts are recognized for their significant role as generators of employment and associated commerce within urban areas. This study describes a method for analyzing the physical characteristics of urban work precincts in promoting the health and wellbeing of their occupants. The following physical parameters are analyzed: public transport accessibility, green and blue spaces, food environments, fitness facilities, supermarkets, and grocery stores. The parameters are assessed using quantitative spatial analysis based on street network data, as well as point of interest data acquired from OpenStreetMap (OSM). The streets and their intersections are stored in the OSM database as links and nodes, respectively. The evaluation of the performance metrics involves measuring the street network distance from each node to the closest node of interest for each parameter. The metrics are then combined, forming an urban health and wellbeing index (UHWI), which can be used to compare the performance of different precincts. The method was tested by investigating four work precincts in Sydney, Australia, all hosting a large office building belonging to the same business institution. Our results identified two of the four precincts with a high UHWI and resulted in the identification of one underperforming precinct.     

Climatic city: Two centuries of urban planning and climate science in Manchester (UK) and its region

This paper traces the history, and current challenges, of climate science and urban design in Greater Manchester, UK. The Mancunian metropolis is a remarkable example of a ‘climatic city’, one that shapes its climate as much as it is shaped by it. From the efforts to control smoke and clear slums in the 19th century, to today’s race to be at the forefront of ‘green’ and ‘sustainable’ cities, climate is a central actor in Manchester’s history and will likely be so in the near future. We analyse the continuities and inflections of this history of climate science and urban planning in the metropolis by drawing on historical material and interviews with key local stakeholders, to understand the natural, social and political construction of this singular ‘industrial ecology’. Ultimately, we ask whether stakeholders in the Greater Manchester area can overcome existing challenges to go towards a greener, more resilient and sustainable city.     

From a top-down to a bottom-up urban discourse: (re) constructing the city in a family-inclusive way

This paper focuses on urban discourses as powerful instruments intertwined with the dialectic of inclusion and exclusion. First, three dominant contemporary urban discourses developed in the field of urban planning are scrutinized on their inclusiveness of families and daily family life. The attractive city, the creative city and the city as an emancipation machine are examples of urban discourses communicated top-down via reports, debates and media attention. It is argued that these three discourses do not address families as urban citizens nor the very notion of reproduction and its daily manifestation. The exclusionary character of contemporary urban discourses does not only result in a neglect of urban families, it also legitimates non-intervention when it comes to family issues. This conclusion activated the search for an alternative discourse as expanded in the second part of the paper. This alternative discourse is constructed from the bottom-up and is rooted in the day-to-day experiences of urban families themselves. It is a refined discourse, with interrelated geographical scales including the city as a whole, the neighbourhood, the street and the home. This is a city that integrates—as families themselves do—the different domains of life. The city is appreciated for its qualities of proximity, the neighbourhood for its ethnically mixed children’s domains, the street as an urban haven and the house as the place that accommodates private life for each member of the family. This alternative discourse is called the balanced city. The empirical basis is drawn from middle-class urban families in Rotterdam, The Netherlands.     

Spatial analysis and land use regression of VOCs and NO2 from school-based urban air monitoring in Detroit/Dearborn, USA

Passive ambient air sampling for nitrogen dioxide (NO₂) and volatile organic compounds (VOCs) was conducted at 25 school and two compliance sites in Detroit and Dearborn, Michigan, USA during the summer of 2005. Geographic Information System (GIS) data were calculated at each of 116 schools. The 25 selected schools were monitored to assess and model intra-urban gradients of air pollutants to evaluate impact of traffic and urban emissions on pollutant levels. Schools were chosen to be statistically representative of urban land use variables such as distance to major roadways, traffic intensity around the schools, distance to nearest point sources, population density, and distance to nearest border crossing. Two approaches were used to investigate spatial variability. First, Kruskal-Wallis analyses and pairwise comparisons on data from the schools examined coarse spatial differences based on city section and distance from heavily trafficked roads. Secondly, spatial variation on a finer scale and as a response to multiple factors was evaluated through land use regression (LUR) models via multiple linear regression. For weeklong exposures, VOCs did not exhibit spatial variability by city section or distance from major roads; NO₂ was significantly elevated in a section dominated by traffic and industrial influence versus a residential section. Somewhat in contrast to coarse spatial analyses, LUR results revealed spatial gradients in NO₂ and selected VOCs across the area. The process used to select spatially representative sites for air sampling and the results of coarse and fine spatial variability of air pollutants provide insights that may guide future air quality studies in assessing intra-urban gradients.     

Influence of traffic force on pollutant dispersion of CO,NO and particle matter (PM2.5) measured in an urban tunnel in Changsha,China

Environmental safety issues and ventilation problems caused by the construction of urban tunnel have increasingly been attracting people’s attention. Previous studies in China have mainly focused on vehicle emissions and ventilation control technologies in road tunnels, resulting in a research gap on urban tunnel ventilation engineering design. Therefore, a detailed monitoring investigation was conducted from May 22 to June 2, 2013 in Changsha Yingpan Road Tunnel, China. The study aim was to measure the traffic characteristics, air velocity and the carbon monoxide (CO), nitrogen oxides (NO_x) and fine particulate matter (PM_2.5) concentrations in this tunnel, which has two lanes per bore and multiple ramps. Measurement results show that during the workday morning peak, the maximum traffic flow was 1560 passenger-car-unit/h per lane with vehicle speed around 33.6 km/h in the eastbound tunnel, the average air velocity was 3.07 m/s, and the proportion of the light-duty vehicles (LDV) was 97.3%. Under the traffic force (not open fan), the CO and NO average concentrations at the main tunnel outlet were 20.3 ppm and 1.65 ppm, respectively. The gas pollutant concentrations are effectively controlled within the multiple-ramps tunnel and the design air volume flow is noticeably reduced. The traffic air flow was found to provide 32.5% of the required air volume to dilute NO_x in blocked traffic condition (vehicle speed of 10 km/h). In addition, the PM_2.5 concentration is mainly affected by the value of background outside the tunnel. The result can provide a quantitative assessment method to support pollutant concentration control and contribution of requested air volume by traffic flow in urban complex structure tunnel.     

德国空间秩序规划与城市规划、专项规划的空间要素管理与协调

德国经过长期的立法与规划管理实践,形成了联邦、州和地区的空间秩序规划与城市规划、专项规划相互协调的空间管理机制。三者除了在空间要素上各有侧重点,其依法管理的约束对象也存在差别。综合的、跨地方的、指导性的空间秩序规划通过具有强制约束力的目标约束公共机构,基于地方自治的城市规划依法对具体的建设实施进行管理,针对特定用途或综合用途协调的专项规划在特定项目上具有优先权。本文基于对德国空间研究与州域规划学会和杜塞尔多夫行政区地区发展32号办公室的采访,对比了三类规划的空间要素,对法定的"双向反馈原则"和有关冲突协调的法律规定进行解读,总结了德国规划实现有效空间管理的协调机制,为我国国土空间规划体系的依法构建提供借鉴。     

Stochastic modeling of total suspended solids (TSS) in urban areas during rain events

The load of total suspended solids (TSS) is one of the most important parameters for evaluating wet-weather pollution in urban sanitation systems. In fact, pollutants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), phosphorous and organic compounds are adsorbed onto these particles so that a high TSS load indicates the potential impact on the receiving waters. In this paper, a stochastic model is proposed to estimate the TSS load and its dynamics during rain events. Information on the various simulated processes was extracted from different studies of TSS in urban areas. The model thus predicts the probability of TSS loads arising from combined sewer overflows (CSOs) in combined sewer systems as well as from stormwater in separate sewer systems in addition to the amount of TSS retained in treatment devices in both sewer systems. The results of this TSS model illustrate the potential of the stochastic modeling approach for assessing environmental problems.     

Exploring an integrated method for measuring the relative spatial equity in public facilities in the context of urban parks

This paper proposes a new integrated modeling framework that contributes to the evaluation of public facility distribution for spatial equity in urban development. The framework consists of two integrated models—accessibility and mobility—that, based on the gravity model, are integrated as a framework for measuring the relative spatial equities of urban public facilities. They are presented as geographic information system (GIS) and spatial analysis models. The models consider individual traffic behavioral abilities and simulate regional differences in the spatial equities of urban parks. The results show unequal regional spatial development that affects mismatches between urban park services. The accumulated travel time costs associated with different resident traffic mobility and urban park location types affect the access opportunities of residents. This integrated model could be a useful reference to help urban planners analyze, investigate, and adjust the distribution of public facilities in a more equitable manner.     

角色分析与空间计策在城市设计教学中的运用（下）

城市设计在指向未来的发展中面临着一个相反相成的局面：一方面所涉及的社会理论知识越加深广,另一方面对空间形态控制的要求越来越高——二者缺一不可。针对于此,本次城市设计教学改革试点实施“齐步走”的程序,以角色分析和空间计策作为主要手段,从社会分析与空间形态设计这两个基本方面引导和训练学生。最后学生们不约而同地选择了“混搭”作为统一的空间计策,并在此基础上发展出了多样化且合理的空间形态设计成果,证明了本次教学改革的基本成功。