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661.
662.
Exhaust emissions of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin/furan (PCDD/F) congeners, tetra-octa PCDD/F homologues, 12 WHO 2005 polychlorinated biphenyl (PCB) congeners, mono-nona chlorinated biphenyl homologues, and 19 polycyclic aromatic hydrocarbons (PAHs) from three legacy diesel engines were investigated. The three engines tested were a 1985 model year GM 6.2 J-series engine, a 1987 model year Detroit Diesel Corporation 6V92 engine, and a 1993 model year Cummins L10 engine. Results were compared to United States’ mobile source inventory for on-road diesel engines, as well as historic and modern diesel engine emission values. The test fuel contained chlorine at 9.8 ppm which is 1.5 orders of magnitude above what is found in current diesel fuel and 3900 ppm sulfur to simulate fuels that would have been available when these engines were produced. Results indicate PCDD/F emissions of 13.1, 7.1, and 13.6 pg International Toxic Equivalency (I-TEQ) L−1 fuel consumed for the three engines respectively, where non-detects are equal to zero. This compares with a United States’ mobile source on-road diesel engine inventory value of 946 pg I-TEQ L−1 fuel consumed and 1.28 pg I-TEQ L−1 fuel consumed for modern engines equipped with a catalyzed diesel particle filter and urea selective catalytic reduction. PCB emissions are 2 orders of magnitude greater than modern diesel engines. PAH results are representative of engines from this era based on historical values and are 3-4 orders of magnitude greater than modern diesel engines.  相似文献   
663.
Investigations of place have often focused on either place meaning (utilizing interpretive designs) or place attachment (using quantitative measures). Rarely have researchers explored the association between place meaning and place attachment. Hence, this investigation was designed to explore how individuals' attachment to a natural environment is reflected in their depictions of why the resource is meaningful.  相似文献   
664.
Through linkage creation, commodity extraction has the capacity to support local industrial production and capabilities building. Drawing on the experience of supplying inputs into the East African gold mining industry, this paper examines the constraints experienced by local suppliers arising from the purchasing procedures of large mining corporations and specialist construction companies contracted to construct these mines. Lead firms become locked-in to particular ways of working which minimise the opportunities that local suppliers have in providing products and services. After reviewing the situation for local mining suppliers in East Africa, the paper examines ways in which lead firms, the suppliers themselves and others (governments and industry associations) can better support local supplier involvement.  相似文献   
665.
An on-site visitor survey instrument was developed to examine visitor perceptions of resource impacts resulting from backcountry hiking activities. The survey was conducted in the Bear Lake Corridor of Rocky Mountain National Park, CO and examined visitor characteristics that may influence visitor perceptions of specific resource conditions. Findings indicate that visitors are more perceptive of recreation-related resource impacts that are the result of undesirable behavior and, while visitors do perceive resource impacts, visitors tend to be more affected by crowding. Factors such as local ecological knowledge and knowledge of minimal-impact practices positively influence visitor perceptions of resource impacts. These findings support the use of visitor education on ecological knowledge and minimum-impact as a means of increasing visitor awareness of recreation impact issues.  相似文献   
666.
We modeled changes in area of five habitats, tidal-freshwater forest, salt marsh, maritime shrub-scrub (shrub), maritime broadleaf forest (oak) and maritime narrowleaf (pine) forest, in coastal Georgia, USA, to evaluate how simultaneous habitat loss due to predicted changes in sea level rise (SLR) and urban development will affect priority bird species of the south Atlantic coastal plain by 2100. Development rates, based on regional growth plans, were modeled at 1% and 2.5% annual urban growth, while SLR rates, based on the Intergovernmental Panel on Climate Change’s A1B mean and maximum scenarios, were modeled at 52 cm and 82 cm, respectively. SLR most greatly affected the shrub habitat with predicted losses of 35–43%. Salt marsh and tidal forest also were predicted to lose considerable area to SLR (20–45 and 23–35%, respectively), whereas oak and pine forests had lesser impact from SLR, 18–22% and 11–15%, respectively. Urban development resulted in losses of considerable pine (48–49%) and oak (53–55%) habitat with lesser loss of shrub habitat (21–24%). Under maximum SLR and urban growth, shrub habitat may lose up to 59–64% compared to as much as 62–65% pine forest and 74–75% oak forest. Conservation efforts should focus on protection of shrub habitat because of its small area relative to other terrestrial habitats and use by Painted Buntings (Passerina ciris), a Partners In Flight (PIF) extremely high priority species. Tidal forests also deserve protection because they are a likely refuge for forest species, such as Northern Parula and Acadian Flycatcher, with the decline of oak and pine forests due to urban development.  相似文献   
667.
Volunteered geographic information and social networking in a WebGIS has the potential to increase public participation in soil and water conservation, promote environmental awareness and change, and provide timely data that may be otherwise unavailable to policymakers in soil and water conservation management. The objectives of this study were: (1) to develop a framework for combining current technologies, computing advances, data sources, and social media; and (2) develop and test an online web mapping interface. The mapping interface integrates Microsoft Silverlight, Bing Maps, ArcGIS Server, Google Picasa Web Albums Data API, RSS, Google Analytics, and Facebook to create a rich user experience. The website allows the public to upload photos and attributes of their own subdivisions or sites they have identified and explore other submissions. The website was made available to the public in early February 2011 at and evaluated for its potential long-term success in a pilot study.  相似文献   
668.
Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008–2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al3+ compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al3+ and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al3+ were determined in the summer, and the lowest in spring.  相似文献   
669.
Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Andes. These studies documented a range of impacts on vegetation, birds and mammals; including changes in plant species richness, composition and vegetation cover and the tolerance of wildlife of visitor use. There was little research on the impacts of visitors on soils and aquatic systems and for some ecoregions in the Andes. We identify research priorities across the region that will enhance management strategies to minimise visitor impacts in Andean ecosystems.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0550-7) contains supplementary material, which is available to authorized users.  相似文献   
670.
Chemical leasing is a new and innovative approach of selling chemicals. It aims at reducing the risks emanating from hazardous substances and ensuring long-term economic success within a global system of producing and using chemicals. This paper explores how, through chemical leasing, the consumption of chemicals, energy, resources and the generation of related wastes can be reduced. It also analyses the substitution of hazardous chemicals as a tool to protect environmental, health and safety and hence ensure compliance with sustainability criteria. For this, we are proposing an evaluation methodology that seeks to provide an answer to the following research questions: (1) Does the application of chemical leasing promote sustainability in comparison to an existing chemicals production and management system? 2. If various chemical leasing project types are envisaged, which is the most promising in terms of sustainability? The proposed methodology includes a number of basic goals and sub-goals to assess the sustainability for eight different chemical leasing case studies that have been implemented both at the local and the national levels. The assessment is limited to the relative assessment of specific case studies and allows the comparisons of different projects in terms of their relative contribution to sustainable chemistry. The findings of our assessment demonstrate that chemical leasing can be regarded as promoting sustainable chemistry in five case studies with certainty. However, on the grounds of our assessment, we cannot conclude with certainty that chemical leasing has equivalent contribution to sustainable chemistry in respect of three further case studies.  相似文献   
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