湖泊水-沉积物界面DIC和DOC交换通量及耦合关系

以乌梁素海和岱海为研究对象,采用柱状芯样模拟法,开展了2个湖泊水-沉积物界DIC和DOC交换通量及耦合关系研究.结果表明,在夏季90 d的时间内,乌梁素海明水区沉积物表现为上覆水中DIC和DOC的碳源,DIC和DOC的平均释放速率分别为71.07 mmol·(m2·d)-1和185.09 mmol·(m2·d)-1;岱海浅、深水区沉积物整体上表现为上覆水中DIC和DOC的碳汇,浅水区DIC和DOC的平均释放速率分别为155.75 mmol·(m2·d)-1和-1 478.08 mmol·(m2·d)-1,深水区DIC和DOC的平均释放速率分别为-486.53 mmol·(m2·d)-1和-1 274.02 mmol·(m2·d)-1;岱海浅水区和乌梁素海水-沉积物界面DIC与DOC耦合作用(含量、释放速率、总量变化量的同步变化)主要受微生物摄取、微生物或非生物降解及水生植物的影响;岱海深水区水-沉积物界面DIC与DOC耦合作用则主要与Ca CO3共沉淀作用及沉积物中无机碳形态分布特征等有关.总体上,不同类型湖泊或同一湖泊不同湖区的DIC或DOC源/汇功能差异是湖泊类型、离岸距离、湖泊水文地球化学及无机碳形态分布等多种因素综合作用的结果.     

基于线性溶解能关系预测污染物在被动采样材料与环境介质之间的分配系数

半透膜采样装置(SPMD)作为一种重要的被动采样器,被用于监测有机污染物的环境水平.SPMD的采样材料是置于低密度聚乙烯"口袋"中的三油酸甘油酯.根据有机污染物在被动采样材料与环境介质之间的平衡分配系数(包括被动采样材料/空气分配系数K(sA).和被动采样材料/水分配系数K(sw))值,可估算SPMD的采样速率,也可计...     

Oxidation of Toluene on γ-Al2O3 Supported Copper–Manganese Catalysts

Abstract Catalytic incineration of toluene over γ-Al2O3-supported copper–manganese oxide catalysts in the temperature range of 433?K–553?K was investigated using a fixed-bed flow reactor. Catalysts were characterized using Brunauer-Emmett-Teller surface area analysis, scanning electron microscopy, temperature-programmed reduction, temperature-programmed oxidation, X-ray photoelectron spectroscopy, and X-ray diffraction. Incineration of toluene was achieved at temperatures up to 553?K and it was found that the weight ratio of reactants (Cu:Mn) was optimized to be 15:10. Brunauer-Emmett-Teller surface area results had no correlation with the activity of the catalysts. Results of temperature-programmed reduction/temperature-programmed oxidation and X-ray photoelectron spectroscopy showed that the redox peak of the 15Cu-10Mn catalyst shifted at lower temperatures and the binding energy shifted toward higher oxidation levels. These results show that high binding energy and high redox capacity are the causes of...     

Plenty of water,not enough strategy: How inadequate accessibility,poor governance and a volatile government can tip the balance against ensuring water security: The case of Nepal

Water security is arguably the single most important factor regarding the future sustainability of our planet. Without water we have no life, and with depleting freshwater resources conflict can easily ensue. The intersection between hydrology and politics requires a delicate balancing from decision-makers to ensure policy is well-informed and science is well communicated. In this paper, we discuss water issues currently faced by Nepal, a nation where freshwater resources are abundant yet political pressures are threatening future water security. We argue that despite adequate water supplies a nation may still experience severe water insecurity, particularly if effective governance and equitable access are not prioritised. We explore potential policy options necessary to achieve a holistic framework for water resources management, which we suggest, need to consider water resource reliability, accessibility and governance as fundamental pillars for ensuring water security.     

Unusual prenatal presentation of Beckwith–Wiedemann syndrome

When Beckwith–Wiedemann syndrome (BWS) is detected prenatally, it is usually on the basis of macroglossia, exomphalos or enlarged kidneys. We describe a case that presented as gross hepatomegaly and a suspected enlarged pancreas at 20 weeks' gestation, with none of the usual features. Copyright © 2004 John Wiley & Sons, Ltd.     

Environmental,economic and social costs and benefits of a packaging waste management system: A Portuguese case study

The impact of the management of packaging waste on the environment, economic growth and job creation is analyzed in this paper. This integrated assessment intends to cover a gap in the literature for this type of studies, using the specific case study of the Portuguese packaging waste management system (SIGRE).The net environmental benefits associated with the management of packaging waste, are calculated using the Life Cycle Assessment methodology. The results show that, for the categories studied, the impacts associated to SIGRE's various activities are surpassed by the benefits associated to material and energy recovery, with special focus on recycling. For example, in 2011 SIGRE avoided the emission of 116 kt CO₂ equiv. – the equivalent carbon emission of the electricity consumption of 124.000 households in Portugal.The economic impact of SIGRE is evaluated through Input–Output Analysis. It was found that SIGRE's activities also have a significant economic impact. For example, their added value are ranked amongst the upper third of the economic activities with highest multiplier effect at national level: this means that for each Euro of value added generated within SIGRE, 1.25 additional € are added to the rest of the economy (multiplier effect of 2.25).Regarding the social impacts of SIGRE, the number of direct jobs associated with the system is estimated to be more than two thousand and three hundred workers. Out of these, 83% are connected to the management of municipal waste packaging (selective collection and sorting), 15% are connected to the management of non-municipal packaging waste and only 2% are connected to the Sociedade Ponto Verde (SPV, green dot society in English) – the management entity responsible for SIGRE.In general terms, the results obtained provide quantitative support to the EEA (2011) suggestion that moving up the waste hierarchy – from landfilling to recycling – creates jobs and boosts the economy.