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601.
The feasibility of using a chemical reaction-based approach for evaluating and modelling the role of adsorption reactions in determining the geochernical confinement capacity of natural geological barriers is being studied as part of an on-going R & D programme. The confined superficial aquifer underlying the Centre de Stockage de l'Aube facility, a geological barrier for this site, has been used as a case study with the following aims. First, development of a site characterisation protocol and demonstration of its use to determine the principal geochemical characteristics of aquifer materials using batch experiments and to represent the information obtained in terms of a chemical model. The experimental results obtained for Ni2+ partitioning as a function of total Ni, pH, total Ca and total solid can be satisfactorily represented in terms of reactions with an ion exchange site and a single amphoteric surface hydroxyl site with ferrihydrite reaction constants. A second objective is the incorporation of the reactions in a coupled geochemistry/transport code, and to verify the applicability of the coupled code predictions for Ni2+ mass transfer by comparison with the results obtained during column tracer experiments. The breakthrough curve and equilibrium solid phase Ni loading, predicted by a one-dimensional coupled model for a column tracer experiment, agree closely with observed data.Additional studies are underway to reduce model conditionality, to extend the adsorption model to other analogue cations and anions, to incorporate the effect of natural organic matter and to take into consideration precipitation/dissolution of amorphous Fe surface phases. 相似文献
602.
603.
Estuaries and coastal lagoons are characterized by a strong spatial and temporal variability of physicochemical characteristics and productivity patterns. In these environments, the magnitude and direction of the ecological responses to inorganic nutrient increase (i.e. eutrophication) are difficult to predict. In the framework of the project, New Indicators of Trophic state and environmental quality of marine coastal ecosystems and transitional environments (NITIDA), we analysed benthic indicators of trophic state, ecosystem efficiency, and environmental quality in four different transitional environments. The trophic state of the sediments was assessed in terms of quantity and bioavailability of sediment organic C pools; ecosystem efficiency was determined in terms of the prokaryote efficiency in exploiting enzymatycally degraded organic C; environmental quality was determined in terms of meiofaunal diversity. Here, we provide a synopsis of the results obtained and a meta-analysis of the scores assessments obtained using the different ecological indicators of environmental quality and demonstrate that trophic state, ecosystem efficiency, and biodiversity in transitional ecosystems are closely linked. We conclude that the assessment of the environmental quality of transitional ecosystems should be based upon a battery of trophic state indicators and 'sensors' of ecosystem functioning, efficiency, and quality. 相似文献
604.
US Energy Conservation and Efficiency: Benefits and Costs 总被引:1,自引:0,他引:1
D. Pimentel A. Pleasant J. Barron J. Gaudioso N. Pollock E. Chae Y. Kim A. Lassiter C. Schiavoni A. Jackson M. Lee A. EATON 《Environment, Development and Sustainability》2004,6(3):279-305
With increased energy conservation plus the adoption of diverse energy efficient technologies, the US economy could save about 32 quads or about 33% of its current energy consumption, if sound conservation energy use policies were implemented over approximately 10 years. This potential of 32 quads is slightly greater than the current US oil imports. The systems that have the greatest potential to provide major energy savings are transportation, residential energy use, and the food system. Not only saving energy has merit in itself, but it would save US citizens approximately $438 billion per year, helping support the US economy, a high standard of living, and energy security. In addition, this analysis suggests that reducing the $40 billion in taxpayer money spent on subsidies of the energy industries would further increase conservation. 相似文献
605.
厚果含笑(Michelialacei)生长在供给6mmolL-1NO3-(高氮)和2mmolL-1NO3-(低氮)Hoagland溶液的盆栽土中,利用PAM-2100叶绿素荧光仪、Licor-6400LCF荧光叶室和WatersHPLC分别测定叶绿素a荧光参数和类胡萝卜素组分,研究氮营养对光系统II(PSII)光化效率和光或暗下热耗散过程的影响.结果表明,在自然光日进程中叶片的开启PSII反应中心的内在量子效率(Fv/Fm)随光辐射增强而降低.低氮叶片Fv/Fm较高氮叶片降低明显(P<0.05).低氮叶片表现较明显的光抑制现象,反映低氮叶片对光抑制比高氮叶片敏感.高氮叶片比低氮叶片有低的PSII光化效率(ΦPSⅡ,P<0.05).高氮叶片依赖光的ΔpH和叶黄素介导的热耗散效率(ΦNPQ)和光下热耗散速率(JNPQ)则较低氮叶片高(P<0.05),结果反映高氮营养增进光下热耗散效率和速率.高氮叶片的紫黄质(A) 玉米黄质(Z)和叶黄素循环色素的转换态(A Z/V A Z)则较低氮叶片高(P<0.05).高氮叶片有较高光下热耗散(NPQ)和相应较高的(A Z)或(A Z/V A Z),叶片通过叶黄素循环色素以热的形式耗散过剩能;而低氮叶片表现高的总荧光淬灭和暗下热耗散.充足氮叶片有较低的光化效率,增高了光呼吸,并通过增强通过叶黄素循环色素的大量耗散过剩能.结果显示,过量氮输入将降低植物光能利用效率.图6表3参28 相似文献
606.
Chen Ying Zhao Yong & Liu ChangmingSchool of Environment Beijing Normal University State Key Joint Laboratory of Environment Simulation Pollution Control Beijing ChinaChina Institute of Water Resources Hydraulic Research Beijing China 《中国人口.资源与环境(英文版)》2004,2(2)
Water saving and developing water conservation society are the two key strategies both for wise water allocation and sustainable utilization. The paper analyses the connotation of water saving and water conservation society. Essentially, water saving means freeing up water from non-beneficial uses and providing it to some more productive uses. Basic principles for setting indicator are presented by providing efficient use of water, considering social issues and ecological protection. An integrated assessing water saving system aiming at more sustainable and efficient consumption is given considering unbalanced social and economic development in regions and basins. The hierarchy indicator system provides qualified tools to the practice of water conservation and evaluates the value for water conservation society construction. 相似文献
607.
以中国29个省市自治区为研究对象,并以2001~2015年PM2.5年度均值作为衡量霾污染的指标,构建了全要素能源效率对中国霾污染影响的空间杜宾模型.研究表明:中国绝大部分省市的霾污染演变趋势具有倒"U"的特点,这说明中国的霾污染在2001~2015年间经历了先上升后下降的总体变化趋势;无论是采用地理相邻权重还是经济权重,中国省际间的霾污染均存在显著空间集聚效应,这揭示霾污染的治理与控制需要地区间建立恰当的合作机制,避免出现"损人利己"现象;在对一系列经济社会因素控制的基础上,全要素能源效率对霾污染存在显著的负向影响并且具有显著的空间溢出效应,这表明全要素能源效率的提高不仅会显著降低本地区的霾污染水平,还将对周边地区的霾污染产生显著的负向影响;分解方程结果显示,技术进步和技术效率对霾污染的负向效应显著,并且技术进步的直接效应大于技术效率,但两者的间接效应均显著大于直接效应,这揭示了技术扩散对霾污染具有重要的潜在促降效应.因此,在治理霾污染的过程中,要通过不断优化能源结构和开发新能源技术以发挥全要素能源效率的减霾效果,以及通过地区间的交流与合作发挥技术扩散效应在霾污染治理中的作用. 相似文献
608.
1IntroductionAsanunrenewablemineralresource,phosphorusisoneoftheimportantesentialelementsforlivingbeings.Phosphorushasmadeagr... 相似文献
609.
610.
以Hg(NO3)2、Cu(NO3)2水溶液为模拟工业废水,以侧链具N、S配位基的网状聚合物冠醚为吸附剂,研究了聚合物冠醚对HP(2+)、Cu(2+)的吸附性能。讨论了溶液温度、pH值、金属离子浓度及时间对吸附性能的影响,该聚合物冠醚对Hg(2+)具有较高的吸附容量和较快的吸附速度。 相似文献