闽江福州段与城市内河表层沉积物重金属污染特征研究

为了探讨城市内河对闽江福州段重金属污染的影响特征,本文对闽江福州段和福州城市主要内河表层沉积物中的Cr、Ni、Cu、Zn、As和Pb 6种重金属元素进行了系统的分析,并采用地累积指数法和潜在生态风险评价法进行污染情况和潜在危险评估.研究结果表明,表层沉积物中重金属Cr、Ni、Cu、Zn、As和Pb含量范围分别为:5.55~131.35、0.74~138.82、2.45~95.84、24.24~609.72、2.82~95.90、13.91~108.45mg·kg~(-1),各重金属含量平均值明显高于福建省土壤环境背景值,但低于国家土壤环境质量Ⅱ类标准值(除As略高于Ⅱ类标准).地累积指数法评价结果表明,表层沉积物中重金属大多为无污染或中污染程度,受人类活动影响强烈.潜在生态风险评价法表明,表层沉积物中重金属Cr、Ni、Cu、Pb和Zn存在轻微潜在风险,As以中等潜在风险为主,总体存在轻微潜在风险.重金属污染物的空间分布与福州市的发展格局相适应,人类活动集中的老城区和工业密集区,是闽江与内河重金属污染物含量相对较高的区域.城市内河汇入闽江后,携带的大量重金属污染物加剧了闽江重金属污染.建议加强对闽江重金属含量较高的晋安河段、光明港段-磨溪河段的污水排放监控.     

A Street Categorization Method to Study Urban Noise: The Valladolid (Spain) Study

Abstract We describe the application of a categorization method for road traffic noise (TN) evaluation. The method assumes that urban noise is stratified according to a five-category classification of streets based only on their use as communication routes. The method has previously been shown to be valid for towns under 220,000 inhabitants, and in the present case is applied to study the urban noise in Valladolid (Spain), a town with a population of nearly 320,000 inhabitants. Novel mathematical tools in this field are used to analyze the method. We demonstrate the existence of a stratification of the streets sound levels. Thus, the categories defined seem to be quite adequate for towns of this size range. Moreover, noise level predictive capacity of the method was also analyzed, and an overall value for the predictive capacity of 80% was obtained. Thus, our method can be a simple, low-cost strategy to make a statistical evaluation of the TN in a city.     

Hybridization,agency discretion,and implementation of the U.S. Endangered Species Act

The U.S. Endangered Species Act (ESA) requires that the “best available scientific and commercial data” be used to protect imperiled species from extinction and preserve biodiversity. However, it does not provide specific guidance on how to apply this mandate. Scientific data can be uncertain and controversial, particularly regarding species delineation and hybridization issues. The U.S. Fish and Wildlife Service (FWS) had an evolving hybrid policy to guide protection decisions for individuals of hybrid origin. Currently, this policy is in limbo because it resulted in several controversial conservation decisions in the past. Biologists from FWS must interpret and apply the best available science to their recommendations and likely use considerable discretion in making recommendations for what species to list, how to define those species, and how to recover them. We used semistructured interviews to collect data on FWS biologists’ use of discretion to make recommendations for listed species with hybridization issues. These biologists had a large amount of discretion to determine the best available science and how to interpret it but generally deferred to the scientific consensus on the taxonomic status of an organism. Respondents viewed hybridization primarily as a problem in the context of the ESA, although biologists who had experience with hybridization issues were more likely to describe it in more nuanced terms. Many interviewees expressed a desire to continue the current case‐by‐case approach for handling hybridization issues, but some wanted more guidance on procedures (i.e., a “flexible” hybrid policy). Field‐level information can provide critical insight into which policies are working (or not working) and why. The FWS biologists’ we interviewed had a high level of discretion, which greatly influenced ESA implementation, particularly in the context of hybridization.     

Assessing impacts on urban greenspace,waterways, and vegetation in urban planning

Parks, waterways, and vegetation enhance the well-being of urbanites and thus warrant consideration in planning and policy-making. It is, however, difficult to assess how land-use change may impact these features and how this in turn may impact well-being. I use a case-study approach to present a framework that combines geospatial and economic valuation techniques to generate indicators of the effects of land-use policies that alter these amenities on community well-being. This framework quantifies the impacts of land-use change on urban environmental amenities in a way that could help communities plan land use so as to maintain well-being as they urbanise.     

Expansion of Urban Space and Land Use Control in the Process of Urbanization: an Overview

Urban expansion brought by the rapid progress of urbanization has caused many problems in China. It is a significant issue to evaluate the extent of urban expansion and to make appropriate controls over the sprawl of urban areas. With a comparative study of international experiences, this article analyzed the mechanism and consequences of urban expansion, reviewed the typical planning and financial policies adopted by other countries for controlling urban sprawl, and discussed the suitable densities of urba...     

Environmental injustice of informal e-waste recycling in Agbogbloshie-Accra: urban political ecology perspective

This paper provides additional empirical knowledge of injustice embedded in the urban governance of informal-sector electronic waste (e-waste) recycling in Ghana. It uses Urban Political Ecology and Environmental Justice perspectives to explain how divergent interest and power among diverse actors in the e-waste sector engender social and environmental (in)justice in Accra. Using the case study approach, this paper reveals that the persistent struggles over interest and power which characterise the governance and management of informal e-waste recycling generate inequity, false accusations, misrecognition, disrespect, devaluation, neglect, exclusion, and abuse of freedom and rights. Inclusive of the finding is the development of local resistance and social movement in defence of interests and against state aggression, oppression, domination and neglect. The study concludes to suggest that the governance of urban socio-economic and ecological space of Accra should involve coordination, participation, holistic inclusion of diverse interest, so as to minimise trade-offs and reap synergies.     

Living the green city: Freiburg's Solarsiedlung between narratives and practices of sustainable urban development

The solar settlement (Solarsiedlung) in Freiburg, Germany, has been widely hailed as an eco-city or green city neighbourhood and a blueprint for sustainable urban development. However, as there is a noticeable lack of critical analysis of what constitutes Solarsiedlung as an “eco-city”, this paper studies narratives and practices of sustainable urban development. First, we look at Solarsiedlung as a best-practice model – a narrative that was produced and perpetuated by architects, urban planners, investors and academics celebrating this neighbourhood as a technologically leapfrogging, economically sound and socially integrated project. Second, we explore the everyday practices and lived experience of the residents in Solarsiedlung. Bringing together these two perspectives, we contribute to a more comprehensive understanding and critical reading of the interplay between the ecological, economic and social dimensions of sustainable development as seen from different viewpoints. Findings indicate that Solarsiedlung as a best-practice model is embedded in growth-oriented neoliberal strategies that are in conflict with the everyday practices and lived experience of the residents. Our findings put into question the widely assumed transferability of best-practice models in sustainable urban development.     

The role of scale in integrating climate change adaptation and mitigation in cities

By using a scale framework, we examine how cross-scale interactions influence the implementation of climate adaptation and mitigation actions in different urban sectors. Based on stakeholder interviews and content analysis of strategies and projects relevant to climate adaptation and mitigation in the cities of Copenhagen and Helsinki, we present empirical examples of synergies, conflicts and trade-offs between adaptation and mitigation that are driven by the cross-scale interactions. These examples show that jurisdictional and institutional scales shape the implementation of adaptation and mitigation strategies, projects and tasks at the management scale, creating benefits of integrated solutions, but also challenges. Investigating the linkages between adaptation and mitigation through a scale framework provides new knowledge for urban climate change planning and decision-making. The results increase the understanding of why adaptation and mitigation are sometimes handled as two separate policy areas and also why attempts to integrate the two policies may fail.     

Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater1

Schiff, Kenneth C. and Liesl L. Tiefenthaler, 2011. Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater. Journal of the American Water Resources Association (JAWRA) 47(1):136‐142. DOI: 10.1111/j.1752‐1688.2010.00497.x Abstract: Despite broad observations of first flush within storms, the scientific understanding of seasonal flushing remains incomplete. Seasonal flushing occurs when initial storms of the season have greater concentrations or loads than storms later in the season. The goal of this study was to census stormwater concentrations and loads from an arid, urban watershed to quantify seasonal flushing. Samples were collected every 15 min during the 1997‐1998 wet season from the Santa Ana River and analyzed for total suspended solids. Initial storms of the season generated event mean concentrations 3‐10 times the event mean concentration of storms later in the season. Cumulative flow‐weighted mean concentrations were calculated as the season progressed. Early season storms discharged only 6% of the annual volume, but influenced flow‐weighted mean concentrations well past the midpoint of the wet season. Mass‐based estimates also indicated a disproportionate load in the early portion of the year; over 52% of the annual load was discharged in the first 30% of the annual volume from the highly urbanized lower watershed. Other stormwater pollutants, including six trace metals (Cd, Cr, Cu, Pb, Ni, Zn), were highly correlated with total suspended solids and also exhibited a significant seasonal flush.     

Occupational Safety and Health Status of Sanitation Workers in Urban Areas: A Pilot Study From Wuhan,China

Sanitation workers ‘ workload increases quickly with rapid urbanization, but there is almost no evidence or policy recommendations for their management in developing countries. This study describes the health status and occupational protection of sanitation workers; it also explores risk factors related to their health status in Wuhan City, China. Three hundred and eighty-five sanitation workers from 54 streets of Wuhan were surveyed. Their prevalence of 2-week illness and arthritis was relatively higher than in the general population in China. Findings related to occupational protection showed that both sanitation workers (users) and their managers (providers) neglected the role of low-cost protection measures, especially masks, soap/hand sani-tizer and prejob training (use rate of 7.27%, 26.75% and 43.64%, respectively). High-intensity workload was an important risk factor for 2-week illness, and prejob training was an important protective factor against arthritis.