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871.
Rose N. L. Shilland E. Yang H. Berg T. Camarero L. Harriman R. Koinig K. Lien L. Nickus U. Stuchlík E. Thies H. Ventura M. 《Water, Air, & Soil Pollution: Focus》2002,2(2):251-260
Spheroidal carbonaceous particles(SCPs) are produced only from high temperaturecombustion of fossil-fuels. In mountain lakesystems, they provide an unambiguous indicator ofatmospheric deposition. In order to comparedepositional fluxes of SCPs between mountainareas experiencing various pollutant regimes,intensive bulk deposition sampling was undertakenat five sites across Europe. Catchment soil coresand lake sediment cores were also taken at eachsite to compare SCP storage over the post-industrial period. Atmospheric, sediment and soilSCP data showed similar patterns. Highestcontamination was found in Scotland, Slovakia andSpain with the Austrian site intermediate and themid-Norwegian site least contaminated. A highproportion of accumulated SCPs were found to bestored in catchment soils at each site.Therefore, a significant increase in soilerosion, possibly as a result of future climatechange, could lead to the input of largequantities of catchment stored SCPs and, byimplication, other atmospherically depositedcontaminants to the lake ecosystem. 相似文献
872.
Mihail Ionescu Zoran S. Petrović Xianmei Wan 《Journal of Polymers and the Environment》2007,15(4):237-243
Soybean polyols prepared by ring opening reactions of epoxidized soybean oil with hydrogen active compounds (water, alcohols,
organic or inorganic acids, thiols, hydrogen etc.) have a low reactivity in the reaction with isocyanates because the hydroxyl
groups are secondary. This paper presents a simple and convenient method to increase the reactivity of soybean polyols with
secondary hydroxyl groups by ethoxylation reactions with the preservation of triglyceride ester bonds. The method uses mild
reaction conditions: low alkoxylation temperature of 35–45 °C, low pressure of 0.1–0.2 MPa (15–30 p.s.i.) and a superacid
as catalyst (HBF4). The new soybean polyols have a higher reactivity toward isocyanates in polyurethane formation due to the high percentage
of primary hydroxyl groups. The primary hydroxyl content was determined by the second order kinetics of polyol reaction with
phenyl isocyanate. 相似文献
873.
Christos Giannakopoulos Effie Kostopoulou Konstantinos V. Varotsos Kostas Tziotziou Achilleas Plitharas 《Regional Environmental Change》2011,11(4):829-843
Climate changes in the Mediterranean region, related to a significant increase in temperature and changes in precipitation
patterns, can potentially affect local economies. Agriculture and tourism are undoubtedly the most important economic sources
for Greece and these may be more strongly affected by changing future climate conditions. Climate change and their various
negative impacts on human life are also detected in their environment; hence this study deals with implications, caused by
changing climate, in urban and forest areas. Potential changes for the mid-twenty-first century (2021–2050) are analysed using
a high-resolution regional climate model. This paper presents relevant climatic indices, indicative for potential implications
which may jeopardise vital economic/environmental sectors of the country. The results provide insights into particular regions
of the Greek territory that may undergo substantial impacts due to climate change. It is concluded that the duration of dry
days is expected to increase in most of the studied agricultural regions. Winter precipitation generally decreases, whereas
an increase in autumn precipitation is projected in most areas. Changing climate conditions associated with increased minimum
temperatures (approximately 1.3°C) and decreased winter precipitation by 15% on average suggest that the risk for forest fires
is intensified in the future. In urban areas, unpleasantly high temperatures during day and night will increase the feeling
of discomfort in the citizens, while flash floods events are expected to occur more frequently. Another impact of climate
change in urban regions is the increasing energy demand for cooling in summer. Finally, it was found that continental tourist
areas of the Greek mainland will more often face heatwave episodes. In coastal regions, increased temperatures especially
at night in combination with high levels of relative humidity can lead to conditions that are nothing less than uncomfortable
for foreigners and the local population. In general, projected changes associated with temperature have a higher degree of
confidence than those associated with precipitation. 相似文献
874.
875.
Benjamin K. Sovacool 《Environment, Development and Sustainability》2007,9(2):187-201
Contrary to claims from American politicians, lobbyists, and oil and gas executives, allowing energy development in the Alaskan
Arctic National Wildlife Refuge (ANWR) will harm the environment, compromise international law, erode the social significance
of wilderness protection, and ultimately fail to␣increase the energy security of the United States. After exploring a brief
history of the ANWR controversy, this piece argues that the operation of oil and gas refineries in ANWR will release discharged
solids, drilling waste, and dirty diesel fuel into the ecosystem’s food-chain, as they have from oil operations in Prudhoe
Bay. Less obvious but equally important, oil and gas exploration in ANWR will violate a number of international treaties on
biodiversity protection. In the end, development in ANWR will threaten the concept of wilderness protection, and will do little
to end US dependence on foreign sources of energy.
About the Author: Benjamin K. Sovacool is a doctoral candidate in the Department of Science and Technology Studies at the Virginia Polytechnic
Institute & State University in Blacksburg, Virginia. He works as a research analyst for the Consortium on Energy Restructuring
and is a Senior Research Fellow for the Virginia Center for Coal and Energy Research. He also just completed a Graduate Fellowship
in Energy Policy at the Oak Ridge National Laboratory in Oak Ridge, Tennessee.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
876.
Ian Calder Ashvin Gosain M. S. Rama Mohan Rao Charles Batchelor M. Snehalatha Emma Bishop 《Environment, Development and Sustainability》2008,10(4):537-557
This paper recommends a revision of watershed development policy in India in relation to the planning of development interventions
involving agricultural intensification and rainwater harvesting following biophysical and societal impact studies carried
out on two watershed development projects in Karnataka. A need for changes in policy has arisen in response to progressive
catchments closure at the basin level and declining volumes of water flowing into village level reservoirs (known locally
as tanks). Flow reductions have occurred largely as a result of increased agricultural intensification over the past 10–15 years.
Field levelling, field bund construction, soil water conservation measures, farm ponds, the increase in areas under horticulture
and forestry and the increased abstraction and use of groundwater for irrigation are all contributing factors to reduced flows.
Planning methodologies and approaches, which may have been appropriate 20 years ago for planning water harvesting within watershed
development projects, are no longer appropriate today. New planning approaches are required which (1) take account of these
changed flow conditions and (2) are also able to take account of externalities, which occur when actions of some affect the
livelihoods of others who have no control or influence over such activities and which (3) contribute to the maintenance of
agreed minimum downstream flows for environmental and other purposes.
相似文献
Ian CalderEmail: |
877.
This study deals with the emission of methane in relation to changing environmental conditions and human impact, in three
mangrove ecosystems of south India. Time-varying fluxes of methane adopting the close chamber technique were used to estimate
CH4 emission from an unpolluted site (Pichavaram mangroves) and two polluted sites viz. (1) Ennore Creek mangroves (affected
by fertilizer effluents and crude oil discharges) and (2) Adyar estuary mangroves (affected by the discharges of organic and
industrial wastes), covering monthly and seasonal variations. The results indicate annual average CH4 emissions of 7.4, 5.02 and 15.4 mg m−2 h−1 from the sediment–water interface of the Pichavaram, Ennore Creek and Adyar estuary respectively. Emission characteristics
obtained at Pichavaram mangroves represent a natural variability with changing physico-chemical factors, whereas the emission
characteristics at Ennore Creek and Adyar estuary mangroves show anthropogenic influence. Several environmental factors such
as oxygen availability, organic matter, soil physical and chemical properties, in addition to human-mediated interventions
have been identified as influencing emission rates in the mangrove ecosystems. Preliminary CH4 emission estimates for the mangrove ecosystems along the Indian sub- continent and the tropical and subtropical coastline
of the world by linear extrapolation based on surface area range from 0.05 to 0.37 and 2.8 to 19.25 Tg CH4 year−1 respectively. Our results also highlight the impact of human activities on future emission of methane from the mangrove ecosystems.
Received: 3 March 1999 / Accepted: 14 September 1999 相似文献
878.
Pan Chen Megan Culbreth Michael Aschner 《Environmental science and pollution research international》2016,23(14):13802-13810
It has become increasingly apparent that global manganese (Mn) pollution to air and water is a significant threat to human health. Despite this recognition, research is only beginning to comprehend the detrimental effects of exposure. Mn, while essential, is particularly harmful to the central nervous system, and overexposure is symptomatic of several neurological disorders. At-risk populations have been identified, but it is still unclear whether typical exposure levels have any long-term consequences. Those at an elevated risk have diminished intellectual function, learning and memory, and mental development. While the overall mechanism of toxicity is undetermined, Mn has been found to induce oxidative stress, exacerbate mitochondrial dysfunction, dysregulate autophagy, and promote apoptosis, ultimately enhancing neurodegeneration. Extrapolation of this in vitro and in vivo data to humans is difficult. There is a definite need to correlate epidemiological studies with causative effects. It is imperative that research efforts endure, so threats are appropriately identified and exposure properly regulated. 相似文献
879.
A. P. Novoselov 《Russian Journal of Ecology》2018,49(2):143-151
The general characteristics of ichthyofauna from the Northern Dvina River are obtained. Based on the results of ichthyological surveys in 1984–2012, as well as bibliographical and archival data, the present composition of the fish community is presented with an accounting of introduced and self-colonized species. The taxonomic status of fish and their belonging to various faunal complexes is considered. In the ecological aspect, the belonging of fish to different ecological groups differing in the feeding and natural reproduction (spawning substrate, methods of spawning, and spawning periods) is distinguished. 相似文献
880.
Increasingly, performance measurement is being used to hold federal agencies accountable, represent environmental progress, and evaluate the effectiveness of environmental programs. The need to track measurable outputs has created a tendency to present programmatic progress solely by quantifiable data, despite the inherent complexity of natural resource management. Wetlands and fire management programs are two specific environmental arenas that have come to overemphasize the tracking of acreage numbers to validate existing policy direction. In both of these arenas, we find the definition and categorization of "countable" acres to be inconsistent and unreliable. We explore this systemic flaw for both wetlands and fire programs and describe its implications for environmental policy and natural resource management more broadly. We conclude with recommendations for improved performance measurement in these arenas. 相似文献