One of the most significant environmental problems arising from landfills is the emission of methane into the atmosphere. In this study, methane emissions from a currently in-use Spanish landfill were modeled as well as being experimentally measured using a two-step method. The first step involved a qualitative walkover survey to detect where gases were being emitted on the surface of the landfill. The second stage comprised a quantitative analysis of these surface methane emissions at a selected number of points on the landfill surface using a specially designed flux chamber. The statistical analysis of the data obtained was based on the Sichel function and resulted in an average emission rate of 74.9 g·m?2·day?1, with 27.8 and 202.1 g·m?2·day?1 as the lower and upper limits of the 95% confidence interval, respectively. The total emission for the landfill, with an emitting surface of 335,000 m2, is 9.16 × 103 ton/yr. These values have been compared with those from three different models, with the model results being above the calculated mean emissions measured at the landfill, but below the upper confidence limit at 95%.
Implications: One of the main environmental problems arising from the presence of landfills is the emission of biogas (which mainly contains methane and carbon dioxide) into the atmosphere. Several experimental methods as well as models have been developed to quantify these emissions. In this work, the authors have compared the results obtained using experimental measurements with those provided by some local and international models using the default parameters proposed. The results obtained from the experimental method are in accordance with those provided by the models, although the models could be slightly overestimating these emissions. 相似文献
In order to further understand the contamination of the citrus pulp pellets (CPP) that were exported to Europe in 1997 we examined both contaminated lime and CPP samples for the distribution of polychlorinated biphenyls (PCBs) and chlorinated benzenes (tri–hexa). Standard isotope dilution techniques were applied for all samples, which were analysed by selected ion monitoring high resolution GC–MS. Lime that is used in the production of CPP product is highly contaminated with PCBs and chlorobenzenes. 相似文献
This article discusses the importance of social networks as survival strategies, testing the impact of segregation on the structure and organisation of personal networks of low-income individuals. It presents preliminary results of an ongoing study on personal networks of individuals living in situations of poverty in São Paulo. We analyse the characteristics of 89 personal networks of poor individuals living in three urban locations, characterised by different social contents and different contexts of segregation. The results indicate a considerable heterogeneity of networks (in terms of size, diversity of sociability spheres, among other dimensions) and a strong localism, which is commonly found in the three different urban contexts. At the same time, the analysis suggests a low impact of segregation and a more complex relationship between networks and space than previously described by the international literature. 相似文献
Summary. Scent signals are the main source of information transmission in carnivores, being particularly important for those with nocturnal
habits like the ringtail (Bassariscus astutus), a Procyonid widely distributed in Mexico. However, faecal marking behaviour of free-ranging ringtails has not been described
previously. The aims of this study were to describe the use of latrines in ringtails and to test if single faeces and latrines
have a marking function, based on the spatial characterisation of the defecation places and revisits to these sites. The study
was conducted at an urban reserve within Mexico City in 2003, where 80 defecation points were analysed. The results showed
that ringtails deposit faeces repeatedly in the same sites (latrines), which contain a variable number of faeces (between
2 and 19). The spatial distribution of latrines was not random, but a selection of substrates and zones that enhanced the
effectiveness as faecal marks was observed. Latrines were preferentially placed on objects above ground level and at road
margins. Latrines and single faeces that were in inconspicuous zones were generally deposited on conspicuous substrates and
latrines and single faeces that were in conspicuous zones were deposited more frequently on inconspicuous substrates. 相似文献
While in many cases the benefits of ecosystem services (ES) can be enjoyed on different scales, the provision of ES requires engagement and commitment at the local scale. Therefore, the local level becomes important when thinking about compensation schemes or payments for ecosystem services (PES) as an approach to managing ES. The difficult task of bringing together different actors and institutions at different scales for specific conservation projects at the local level often remains in the hands of intermediaries. In this paper, we investigate the role of a civil society organisation (CSO) as an intermediary organisation in a PES scheme, the Community Blue Carbon Project (CBCP) in Costa Rica. To assess the role of intermediaries in a PES scheme, we rely on social network analysis and examine the position and role of the intermediary organisation. Based on Net-Map interviews, which is an interview-based mapping tool that helps people understand, visualise, discuss and improve situations in which many different actors influence outcomes, we find that the intermediary organisation in the CBCP is composed of several institutional and individual intermediaries who create both formal networks for connecting the international to the local level and informal networks for creating trusting relationships among the actors. Different spatial levels are reflected within the CSO’s organisational structure, and the CSO mitigates the distributional, procedural, recognition and contextual aspects of environmental justice. 相似文献
Humans are rapidly depleting critical ecosystems and the life support functions they provide, increasing the urgency of developing
effective conservation tools. Using a case study of the conversion of mangrove ecosystems to shrimp aquaculture, this article
describes an effort to develop a transdisciplinary, transinstitutional approach to conservation that simultaneously trains
future generations of environmental problem solvers. We worked in close collaboration with academics, non-government organizations,
local government and local communities to organize a workshop in Puerto Princesa, Palawan, Philippines. The primary objectives
of the workshop were to: (1) train participants in the basic principles of ecological economics and its goals of sustainable
scale, just distribution and efficient allocation; (2) learn from local community stakeholders and participating scientists
about the problems surrounding conversion of mangrove ecosystems to shrimp aquaculture; (3) draw on the skills and knowledge
of all participants to develop potential solutions to the problem; and (4) communicate results to those with the power and
authority to act on them. We found that the economic and ecological benefits of intact mangroves outweigh the returns to aquaculture.
Perversely, however, private property rights to mangrove ecosystems favor inefficient, unjust and unsustainable allocation
of the resource—a tragedy of the non-commons. We presented the workshop results to the press and local government, which shut
down the aquaculture ponds to conserve the threatened ecosystem. Effective communication to appropriate audiences was essential
for transforming research into action. Our approach is promising and can be readily applied to conservation research and advocacy
projects worldwide, but should be improved through adaptive management—practitioners must continually build on those elements
that work and discard or improve those that fail. 相似文献