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851.
Modern science is global. This is particularly true of environmental science, which has been guided to a considerable extent by international environmental policy. Accordingly, one might expect the standards of scientific research around the globe to have unified over the last 30 years. Yet environmental scientists from different nations and scientific schools have demonstrably dissimilar views on key environmental issues. This is the conclusion we reached after a series of in-depth interviews with prominent American and Russian environmental scientists. The greatest difference was found in the perception of two global issues—stratospheric ozone depletion and climate change.  相似文献   
852.
The major problem associated with gravity dam was siltation of reservoir which reduced its effective water storage capacity. In order to maintain effective storage capacity of reservoir, dredging of deposits was required and dredged material was disposed of haphazardly causing damage to the sensitive environment. A better alternative could be the possibility of utilization of dredged deposits in construction works involving large quantities of material. The dredged material consisted of very fine sandy silt possessing poor geotechnical characteristics and was required to be stabilized with suitable additives before use as construction material. This laboratory investigation evaluated geotechnical properties of dredged reservoir material stabilized with cement, fly ash and fiber for its probable use as subbase in lightly trafficked roads. Compaction, unconfined compressive strength and tensile strength tests were performed on appropriate combinations of the constituent materials. The results of study revealed significant improvement in unconfined compressive strength and split tensile strength after stabilization with cement and fly ash. The unconfined compressive strength and split tensile strength of cement–fly ash-stabilized dredged reservoir material improved further upon addition of polypropylene fiber. The composite possessed the potential to be utilized as sustainable material in subbase of roads subject to further validation before application in the field. The dredging of sediments improved effective storage capacity of reservoir and increased its sustainable life period. The utilization of fly ash could diminish the environmental and economic concerns arising out of its haphazard disposal.  相似文献   
853.
Assessment of physicochemical parameters of Ganga Canal water was carried out during 2012–2013 at Haridwar (Uttarakhand) with two different sites, i.e., Bhimgoda Barrage (site 1—control site) and Bahadrabad (site 2—contaminated site), where canal water flows with loads of pollution from highly commercial and industrial areas. During investigation, maximum turbidity (287.72 ± 56.28 JTU), total solids (1167.60 ± 303.90 mg l?1), free CO2 (1.88 ± 0.22 mg l?1), total hardness (60.14 ± 1.13 mg l?1), pH (7.1 ± 0.13), nitrate (0.048 ± 0.010), nitrite (0.019 ± 0.001), biochemical oxygen demand (2.866 ± 1.098), chemical oxygen demand (6.8 ± 2.61) and phosphate (0.087 ± 0.015), while minimum velocity (1.71 ± 0.19 ms?1), transparency (0.12 ± 0.08 m) and dissolved oxygen (7.95 ± 0.44 mg l?1) were recorded in monsoon season at site 2 in comparison with site 1. The mean values of these parameters were compared with WHO and ISI standards and found significant differences (p < 0.05) in the mean values of turbidity, total solids, pH, dissolved oxygen, free CO2 and total hardness with sampling sites. The turbidity of both the sites 1 and 2 was recorded above the permissible limit. Turbidity of site 2 is much higher than of site 1, so it is counted as more polluted. The values of the studied parameters were more during monsoon season and summer season at site 2 as compared to site 1. The results indicated that most of the physicochemical parameters from Ganga Canal system were within or at periphery in comparison with permissible limit of ISI and WHO for drinking water and therefore may be suitable for domestic purposes, but it requires perceptible consideration due to intense changes in climate and increase in pollution.  相似文献   
854.
From the ontological point of view, environmental health problems do not differ from problems of unsustainability. This leads us to think that sustainability science could contribute to resolve important questions that studies on environmental health are not resolving. A literature review was made in order to analyse the scope and limitations of studies on environmental health problems. Based on the characteristics of environmental health studies, we highlighted some examples of questions that are being ignored and analysed four contributions that sustainability science could make to solve them. These contributions come from three key components of sustainability science: (1) the unit of analysis—social–ecological systems, (2) a theory—resilience theory and, specifically, social–ecological resilience, (3) and the approaches of complex systems and transdisciplinarity. From a sustainability science perspective, four contributions could be made: environmental health problems are redefined as social–ecological systems; environmental health is assumed to be the result of adaptation processes; the environment and society are recognized as systems, not as matrices of factors; and human action acquires content and structure and, in turn, explains the behaviour of environmental health problems.  相似文献   
855.
Tehran metropolitan region (TMR) has experienced rapid urbanization in the last few decades. This accelerating urbanization trend mainly arising from high natural population growth and rural–urban migration along with rapid socioeconomic changes formed unplanned and uncontrolled urban expansion in peri-urban areas and resulted in degrading environmental quality and considerable changes in the urban landscapes of the TMR. Thus, the main objective of this research is to model spatial pattern of urban growth in eastern corridor of TMR using GIS-based SLEUTH model and the prediction of future developments of the region from 2014 to 2060. The SLEUTH is one of the most powerful models for urban growth modeling. This model analyzes the spatial pattern of urban growth based on historical data obtained from satellite images of 1987, 2003, 2011, and 2014. The results indicate that the most important factors affecting the urban growth are slope resistance and road gravity. The slope resistance is the highest coefficients value, which illustrates the limiting influence of the slopes on general trend of urban growth in eastern corridor of the TMR. The road gravity stands in second place where it displaces orientation of linear form of outlying pattern alongside the transportation network; it represents that the main pattern of urban growth in peri-urban areas of the region have a linear nature and edge expansion due to slope resistance and road-influenced growth, while spread, diffusion, and breed coefficients display low probability of new spreading center and spontaneous growth in the study area. In addition, the prediction of urban growth for 2020–2060 revealed that urban expansion which was 41,500 ha in 2014 will increase to 179,400 ha in 2060 with noticeable growth rate of 145.6 %. Comparing study area and other researches indicate that the urban growth happens in high rate in eastern corridor. One of the main reasons of this growth goes back to the formation of the second homes for residents of Tehran metropolitan city.  相似文献   
856.
Coastal Regulations in India are traced back to the UN Conference on Human Environment, held in Stockholm in 1972. The Environment Protection Act (EPA) 1986 was enacted to implement India’s commitments as a signatory. The Coastal Regulation Zone (CRZ) Notification of 1991 was made under the provisions of the EPA in order to protect coastal environments and social and livelihood security of fishing community. This paper assesses the effects of CRZ rules and violations in the Mumbai Metropolitan Region, which has experienced tremendous growth due to the rapid industrialization and urbanization. This process has led to the destruction of mangroves and other important species of fish which play a crucial role in sustaining the coastal ecology and urban biodiversity; high population density and uneven growth have exacerbated adverse environmental and socioeconomic consequences. The Koli (fishing community) in this region faces huge problems of survival and sustenance in small-scale fishing, due to the rampant commercial fishing by big trawlers and large-scale dumping of waste materials by the industries surrounding the vicinity into the sea. In small but significant ways, the fishing communities through their traditional commons-based resource management and livelihood systems protect the coastal ecology and help the cities in reducing their carbon footprints. On the basis of primary field research in Thane–Mulund Creek Bhandup, Chimbai, and Sewri, this paper attempts to assess CRZ violations taking place on coastal areas and is causing damage to the coastal ecology. The research specifically has focused on the particular fishing-related activities and spaces—such as: jetties, parking of boats, access to sea, weaving and drying of nets, landing grounds, drying and cleaning of fish that are more affected by encroachment of seashore area and by CRZ rules violations. It evaluates the actions taken by Maharashtra Coastal Zone Management Authority and Bombay Municipal Corporation while implementing rules and making Integrated Coastal Zone Management plan for management of marine environment. It raises broader issues relating to the contradictions and complementarities involved in ICZM plans vis-a-vis management of biodiversity, within a larger context of rapid urbanization and demands for real estate growth. The paper argues that urban biodiversity management requires clear valuation of the long-term ecological and socioeconomic benefits of sustenance of coastal ecology and related livelihoods.  相似文献   
857.
Eco-certification has been used as a tool to mitigate adverse effects of aquaculture production and might thus be understood as a private approach to sustainable ecosystem management. In production forests in Ca Mau, Vietnam, where mangrove have suffered degradation despite legal protection, different projects have targeted reversing this trend by means of private certification using the ‘Naturland’ organic standard as a reference. So far the outcomes have, however, been proven unsatisfactory. With the aim to better understand the reasons for these poor outcomes, a survey of forty households was conducted in a production forest in Rach Goc commune, Ngoc Hien District. We evaluated farmers’ perceptions on mangrove management, the drivers guiding shrimp farming, and whether there was a difference between participants and non-participants in a former ‘Naturland’ organic project. To complement the survey, a range of stakeholders involved in shrimp value chains were interviewed to better understand the terms and benefits of certification. The results of this survey suggested that, when applied to shrimp–mangrove farming systems in production forests in Ca Mau, ‘eco-certification’ and associated benefits are not very satisfactory. The survey results revealed that certified farms do not show significant differences to non-certified farms in terms of social and environmental benefits. As far as the implementation process was concerned, the survey results showed that a failure to integrate local farmers as participants consequently resulted in households becoming ‘objects’ for certification and not project partners with equal weight and power. It appears that rather than being a tool for improvement, ‘Naturland’ certification for shrimp–mangrove farming systems in Ca Mau’s production forests has become an end in itself.  相似文献   
858.
Irrigation is indispensable to overcome insufficient rainfall and to achieve a stabilized yield for tea production. As the severe scarcity of water resources because of climate change, water conservation through efficient irrigation has turned into a vital strategy for tea sector in solving this rising challenge. This paper analyzes irrigation water use efficiency of small-scale tea farms in Vietnam and identifies its determinants applying stochastic frontier analysis. Results showed that under decreasing returns to scale, the mean irrigation water use efficiency was 42.19 %, indicating the existence of substantial water waste. If farmers become more efficient in using water, saving 57.81 % of irrigation water is possible unaccompanied by reducing the observed output. The factors affecting tea farms’ irrigation water use efficiency were investigated by Tobit model. Gender, water shortage awareness, soil and water conservation practice, off-farm income share, extension services access and well water utilization showed significant influence on the efficiency of irrigation water. The study’ results provide insights to policymakers in implementing better water resource management amid climate change.  相似文献   
859.
Decentralized power generation, using locally available biofuels from non-edible oilseeds, is an option for rural electrification in many developing countries. However, due to prevailing high price of non-edible oilseeds, such as Jatropha curcas, the cost of electricity generation is very high. This paper provides detailed financial analysis of straight vegetable oil (SVO)-based decentralized power project and proposes an innovative model for enhancing their financial viability. While for implementing agency operational cost recovery is the key for viability, affordable tariff is crucial for end-users. The paper attempts to estimate minimum desired price of electricity from the stakeholders' (producer and users) perspective using data gathered from selected operational SVO-based power generation projects in India. Analysis carried out in this paper indicates that operating the decentralized power plant at higher capacity utilization factor, by introduction of productive load, and differentiated tariffs for commercial and domestic consumers may not alone be sufficient to achieve the financial viability. The paper proposes an innovative integrated model of using biogas, obtained from the by-product de-oiled cake of non-edible oilseeds, as a feedstock for power generation, instead of using the SVO in engines. This reduces the fuel cost of power generation, thereby helping to bring down the tariff within the paying capacity of rural consumers. The main produce, viz. extracted non-edible oil, which was otherwise used as fuel for generating power, can be sold in local market for earning revenue, thereby enhancing the project’s economic viability. This paper sets forth the proposed integrated model as a viable biofuel-based decentralized power project for sustainable rural development in areas with adequate availability of oilseeds.  相似文献   
860.
The hunting of wild animals remains a common activity in various parts of the world, especially in rural communities with poor socioeconomic conditions. To investigate patterns of mammal hunting, this study adopted a rural community located in semiarid Brazil as a model to test whether variables such as perceived abundance, activity period (day or night) and animal biomass could influence the consumption potential of mammal taxa. For this study, a checklist/interview technique using 32 photographs of mammals recorded in the region and two photographs of species that did not occur in the region, which acted as “control” species, was used, in addition to other visual stimuli and free lists. All species presented in the photographs, with the exception of the “control” species, were recognized as occurring in the region. Fourteen species were cited as being those most hunted locally. The species cited as most hunted had an average perceived abundance higher than the group of the least-hunted species. However, there was no significant relationship between hunting of a species and its locally perceived abundance. No significant difference in hunting pressure between diurnal and nocturnal species was found, nor was a relationship between animal biomass and hunting pressure observed. Our findings suggest that perceived abundance is an important factor for choosing a resource fauna, but other factors such as intended use, meat flavor and vulnerability to hunting, among others, may influence the potential use of a species.  相似文献   
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