An Integrated Approach Towards Assessing the Value of Water: A Case Study on the Zambezi Basin

The aim of this paper is to develop a methodology for assessing the value of water in the different stages in the water cycle. It is hypothesised that if a cubic metre of water provides some benefit in some spot at a certain moment, this cubic metre of water has a certain value not only at that point in space and time, but in its previous stages within the water cycle as well. This means that, while water particles flow from upstream to downstream, water values ‘flow’ in exactly the opposite direction. The value of water in a certain place is equal to its value in situ plus an accumulated value derived from downstream. This value-flow concept is elaborated for the Zambezi basin. It is found that water produces the smallest direct economic benefits in the upper part of the Zambezi basin. However, water flows in this part of the basin − due to their upstream location − have the highest indirect values. Return flows from the water-using sectors are particularly valuable in the upstream sub-basins. The analysis shows that the value per unit of river water increases if we go from downstream to upstream. Another finding of the study is that percolation of rainwater is generally more valuable than surface runoff. Finally, a plan to export water from the river Zambezi to South Africa is evaluated in terms of its opportunity costs. The results of this study show that the value-flow concept offers the possibility of accounting for the cyclic nature of water when estimating its value. It is stressed, however, that for the current study many crude assumptions had to be made, so that the exact numbers presented should be regarded with extreme caution. Further research is necessary to provide more precise and validated estimates. This revised version was published online in July 2006 with corrections to the Cover Date.     

Photolysis Behavior of Herbicide Propisochlor in Water Media and Preliminary Analysis of Photoproducts Under Different Light Sources

Photolysis behavior of a new herbicide propisochlor in water media as well as the effects of light sources, initial concentration of propisochlor, pH value, dissolved oxygen (DO) level, and salinity on the photolysis process was investigated. It was found that the relationship between initial concentration of propisochlor and its photodegradation rate was negatively correlated. The changes in acidity and alkalinity of the reaction medium influenced the photoreaction rate evidently. In the alkaline solution the degradation was accelerated. In the reaction media with different pH values, the photolysis followed the first-order kinetics. The presence of dissolved oxygen may promote the photolysis and there existed an optimum of dissolved oxygen concentrations. Increasing the DO level can weaken the promotion and even have an adverse effect. It was demonstrated that with dissolved oxygen the photodegradation of propisochlor followed the first-order kinetics equation. The addition of salt ions Ca²⁺ and Mg²⁺ changed the ionic strength and solvent polarity, resulting in the effect on propisochlor photolysis. The photoproducts were detected by both HPLC and GC-MS methods. It was found that photolysis products varied under different light sources. Conclusions may be reached that in the photodegradation of propisochlor, the benzene ring remained intact under irradiation of both solar light and high-pressure mercury lamp, and the amido link was relatively stable, while dechlorination was liable to take place; moreover, α-hydrogen at the substituent of benzene ring was active.     

基于耕地综合价值的土地征收补偿标准研究

由于现行耕地征收补偿仅对耕地的农业经济价值以及部分就业保障价值进行补偿,忽视了耕地的其他价值,导致了耕地征收中的一系列社会经济问题产生.因此,合理制定耕地征收补偿标准对于维护农民土地权益,保护耕地资源具有十分熏要的意义.论文从耕地资源综合价值角度出发,将土地征收补偿标准的构成分解为农业经济价值、社会价值和生态环境价值三部分,并分别采用收益还原法、成本替代法和支付意愿法对他们进行量化测算,并以江苏省南京市为例进行了实证研究.结果表明,按照耕地资源综合价值建立征地补偿标准,农民将比现行征地补偿多获得6.6倍的补偿金,而且由于新的征地补偿能有效将耕地的外部性价值如社会稳定价值和生态环境价值等内部化,清除了耕地征收中的市场失灵,更有利于耕地资源非农化配置效率提高.此外,由于新的征收补偿标准远低于现行的建设用地基准地价,因此,该标准在经济上是可行的,社会可接受的.     

活性污泥胞外聚合物提取方法优化

试验对比了不同离子交换树脂(CER)含量和pH条件下胞外聚合物(EPS)的提取效果差异。结果表明,EPS各组分提取浓度均随离子交换树脂用量增加而增加,但各组分趋势不同。TOC的最佳树脂剂量为100 g CER/g VSS,而蛋白质、多糖和DNA的最佳树脂剂量约为70 g CER/g VSS。pH值对TOC、DNA和多糖的提取浓度影响较小,但对蛋白质影响比较大。各提取条件下,EPS各组分提取浓度随时间的变化过程可以分为平稳增长期、快速增长期及稳定期。     

玛纳斯河流域生态系统服务功能价值研究

土地利用/覆被变化是生态环境演变最重要的因素之一,其研究对于促进区域生态经济协调发展有重要意义。根据1976年和2006年玛纳斯河流域两期遥感影像资料,基于生态经济学的最新方法采用卫星遥感技术以及Costanza等的生态系统服务价值评价手段,对期间玛纳斯河流域生态服务系统服务功能价值变化进行分析研究。结果表明:①玛纳斯流域土地利用结构变化在30年间表现为草地、林地、不断减少,而耕地、水域、沙地和建设用地不断增加,反映出人类因素及生态环境恶化的趋势;②该流域生态系统服务功能价值总额由1976年123.831 08元减少至2006年101.521 08元。减幅:18.02%,年均减少0.741 08元,通过对玛纳斯河流域生态系统服务功能价值进行评价,为玛纳斯河流域生态开发和治理,以及环境整治提供决策依据。     

试论低碳经济背景下的政府职能

伴随着经济与社会的进步,能源短缺与环境污染正愈演愈烈,迫切需要由高碳经济转向低碳经济。中国目前的发展模式与消费结构仍处于高碳状态,因此发展低碳经济势在必行。政府作为经济活动的有机组成部分,应当在发展低碳经济的过程中履行好其对外交流、对内调控的政府职能。     

药食保健野菜——苋菜的开发利用

苋菜是一种具有较高利用价值的药食两用蔬菜,对其进行开发利用已成为国内外医疗保健、食品、化工领域的研究热点。介绍了苋菜的识别特征、固有营养价值、保健作用、微量元素与食疗原理,提出了苋菜资源的开发利用方向。     

引入资源价值补偿机制的资源税改革研究

资源是社会经济发展的基础,也是社会可持续发展的动力和保证,随着我国经济的快速发展,资源短缺现象日益突出,资源补偿不足的问题也日益凸显.国内外研究证明,资源补偿和资源税改革息息相关,资源价值补偿作为一种有效的资源补偿方式,具有很好的适用性和可操作性,是政府调控资源生产、消费和恢复的有效手段之一.长期以来,我国的资源税改革一直受到关注焦点,但学者门多关注于如何提高税率,扩大税基,而忽视了资源税改革中的资源补偿问题.本文首先回顾了相关研究成果,在此基础上借鉴国外经验,在资源税改革中引入资源价值补偿机制,并构建资源环境CGE模型(即RECGE模型),从资源价值补偿对社会经济、资源环境以及社会福利等方面进行模拟分析,研究资源价值补偿的影响.研究表明:资源价值补偿能有效缓解资源压力,改善环境状况,而合理而有效的资源补偿能有效协调经济和资源环境系统,促进社会经济的可持续发展.     

Epiphytic lichen diversity in central European oak forests: Assessment of the effects of natural environmental factors and human influences

We investigated lichen diversity in temperate oak forests using standardized protocols. Forty-eight sites were sampled in the Czech Republic, Slovakia and Hungary. The effects of natural environmental predictors and human influences on lichen diversity (lichen diversity value, species richness) were analysed by means of correlation tests. We found that lichen diversity responded differently to environmental predictors between two regions with different human impact. In the industrial region, air pollution was the strongest factor. In the agricultural to highly forested regions, lichen diversity was strongly influenced by forest age and forest fragmentation. We found that several natural factors can in some cases obscure the effect of human influences. Thus, factors of naturality gradient must be considered (both statistically and interpretively) when studying human impact on lichen diversity.