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991.
Impact of land use changes on water quality in headwaters of the Three Gorges Reservoir 总被引:1,自引:0,他引:1
Huicai Yang Guoqiang Wang Lijing Wang Binghui Zheng 《Environmental science and pollution research international》2016,23(12):11448-11460
The assessment of spatial and temporal variation of water quality influenced by land use is necessary to manage the environment sustainably in basin scales. Understanding the correlations between land use and different formats of nonpoint source nutrients pollutants is a priority in order to assess pollutants loading and predicting the impact on surface water quality. Forest, upland, paddy field, and pasture are the dominant land use in the study area, and their land use pattern status has direct connection with nonpoint source (NPS) pollutant loading. In this study, two land use scenarios (1995 and 2010) were used to evaluate the impact of land use changes on NPS pollutants loading in basins upstream of Three Gorges Reservoir (TGR), using a calibrated and validated version of the soil and water assessment tool (SWAT) model. The Pengxi River is one of the largest tributaries of the Yangtze River upstream of the TGR, and the study area included the basins of the Dong and Puli Rivers, two major tributaries of the Pengxi River. The results indicated that the calibrated SWAT model could successfully reproduce the loading of NPS pollutants in the basins of the Dong and Puli Rivers. During the 16-year study period, the land use changed markedly with obvious increase of water body and construction. Average distance was used to measure relative distribution patterns of land use types to basin outlets. Forest was mainly distributed in upstream areas whereas other land use types, in particular, water bodies and construction areas were mainly distributed in downstream areas. The precipitation showed a non-significant influence on NPS pollutants loading; to the contrary, interaction between precipitation and land use were significant sources of variation. The different types of land use change were sensitive to NPS pollutants as well as land use pattern. The influence of background value of soil nutrient on NPS pollutants loading was evaluated in upland and paddy field. It was found that total nitrogen (TN) and total phosphorous (TP) in upland were more sensitive to NPS pollutants loading than in paddy fields. The results of this study have implications for management of the TGR to reduce the loading of NPS pollutants into downstream water bodies. 相似文献
992.
Jianxin Shou Huaping Dong Jianfa Li Jiaxing Zhong Saijun Li Jinhong Lü Yimin Li 《Environmental science and pollution research international》2016,23(19):19156-19163
Biochars’ properties will change after application in soil due to the interactions with soil constituents, which would then impact the performance of biochars as soil amendment. For a better understanding on these interactions, two woody biochars of different surface areas (SA) were physically treated with aluminum oxide (Al-oxide) to investigate its potential influence on biochars’ sorption property. Both the micropore area and mesopore (17~500 Å in diameter) area of the low-SA biochar were enhanced by at least 1.5 times after treatment with Al-oxide, whereas the same treatment did not change the surface characteristics of the high-SA biochar due partly to its well-developed porosity. The enhanced sorption of the pesticide isoproturon to the Al-oxide-treated low-SA biochar was observed and is positively related to the increased mesopore area. The desorption hysteresis of pesticide from the low-SA biochar was strengthened because of more pesticide molecules entrapped in the expanded pores by Al-oxide. However, no obvious change of pesticide sorption to the high-SA biochar after Al-oxide treatment was observed, corresponding to its unchanged porosity. The results suggest that the influence of Al-oxide on the biochars’ sorption property is dependent on their porosity. This study will provide valuable information on the use of biochars for reducing the bioavailability of pesticides. 相似文献
993.
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
994.
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
995.
996.
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
997.
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: |
998.
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
999.
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
1000.
Richard C. Foltz 《Journal of Agricultural and Environmental Ethics》2007,20(6):533-542