Non-agglutinating cholera-like Vibrios in sewage,surface water and sea water

Routine bacteriological analysis of sewage work effluents and surface waters has not revealed evidence of Vibrio cholerae or Vibrio El Tor, whereas, non-agglutinating cholera vibrios of Heiberg's groups I and II [so-called non-agglutinating strains (NAG)] have been detected quite frequently. This frequency of NAG presence is approximately equivalent to the presence of Salmonella. Depending on local conditions, quantitative studies of equal amounts of sewage resulted in a ratio of about 1 NAG/10²Salmonella/10⁷E. coli.When it became known that NAG vibrios were capable of producing a clinical appearance in man that resembled cholera by its symptoms and severeness, NAG vibrios raised epidemiological interest. Unlike Salmonella, the nutrient requirements of NAG vibrios are moderate. The decisive factors for their persistence in the environmental are attributed to a certain chloride content in the water and an elevated pH value. Both factors are preferably present in sea water. Over a period of 3 yr, samples of water from the Baltic Sea (Lübecker Bucht) were regularly examined for the presence of NAG vibrios. During this period, there have been a number of positive findings in a sample of 100 ml water while identical samples were always Salmonella-negative.     

水资源权属管理改革形势下水权确权登记制度研究

水资源作为一种公共资源,由于其产权制度的不明晰,导致水资源的利用效率低下,污染和浪费现象严重,水环境形势严峻,水资源权属管理制度亟需改革。水资源权属管理应该重点关注水资源的使用权,包括取水权、农村集体经济组织水使用权、少量用水权和应急用水权。水资源确权登记是水资源权属管理改革中的基础和根本环节。文章通过演化博弈模型构建用水户之间的复制动态和进化稳定策略,论证建立水资源确权登记制度的理论支撑,结果表明一个区域内取水量越小,采取超额取水策略的用水户比例越大,当采取超额取水策略的用水户比例较高时,区域内各个用水户的期望收益和整体期望收益都较低,极易造成水资源使用过程中的用水矛盾冲突,而用水户采取限额取水策略能够增加总体的期望收益。本文明确了水资源产权确权与登记制度的主要含义,重点研究了水资源确权登记的范围包括取水权和农村集体经济组织水使用权,并在此基础上明确了取水权和用水权的确权主体和确权内容、水权确权登记的机关、确权和登记的具体程序,提出水资源确权在整个确权登记过程处于主导地位,而登记是取水权交易的前提条件,在此基础上提出对当前取水许可制度进行改革,按照产权制度的要求,强化水权的权属管理和水权的法律保护。据此,本文提出中央机构应与地方政府相互配合,明确分工,密切结合实际,做好水资源确权登记工作,改善水资源权属管理混乱的现状,加快水资源权属管理改革。     

Impacts of climate change on surface water quality in relation to drinking water production

Besides climate change impacts on water availability and hydrological risks, the consequences on water quality is just beginning to be studied. This review aims at proposing a synthesis of the most recent existing interdisciplinary literature on the topic. After a short presentation about the role of the main factors (warming and consequences of extreme events) explaining climate change effects on water quality, the focus will be on two main points. First, the impacts on water quality of resources (rivers and lakes) modifying parameters values (physico-chemical parameters, micropollutants and biological parameters) are considered. Then, the expected impacts on drinking water production and quality of supplied water are discussed. The main conclusion which can be drawn is that a degradation trend of drinking water quality in the context of climate change leads to an increase of at risk situations related to potential health impact.     

Managing the village-level open-access water resources in a region facing rapidly declining water availability

Growing population, human settlements, industrialization and intensification in groundwater-based cultivation have resulted in severe onslaught on underground aquifers in West Bengal, an eastern province of India with high population density. The present paper focuses on this water resource management issue. The study shows that traditional, village-level surface water reservoirs which for centuries had supplemented irrigation in addition to providing water for all sorts of domestic needs are now in doldrums. Through statistical analysis, the study shows that for all practical purposes, there is very little effective management of these precious open-access water resources. The situation calls for paradigm shift in policy on water resource management that entails development of community-based management catalyzed by government intervention, external agencies and NGOs under supervision and control of local elected bodies.     

Evaporation of solutes from water

A model is developed to define the evaporation rates of solutes from water. The rate equation, similar in form to the Knudsen equation, takes into consideration the effect of air and subwater turbulences on the evaporation loss. At given system conditions, the factor accounting for the air turbulence appears to be essentially constant and independent of temperature (3.5–25°C) for various organic chemicals and water. These characteristics allow one to study the rate of evaporation from water and the relative enhancement by subwater mixing for different solutes. This report shows that the volatilization loss of pure substances and solutes with low Henry's law constants is enhanced by air turbulence, not by subwater mixing. However, the loss of volatile solutes (high Henry's law constants) may be promoted both by air turbulence and by subwater mixing, in which the extent of enhancement by liquid mixing is determined primarily by the Henry's law constant. The present model provides a theoretical basis to explain these effects and others, which appear to be important for assessment of pollutant evaporative transport in the environment.     

The human cycle of water: water management and anthropogenic contaminant pathways in Pótam,Sonora, Mexico’s water cycle

Women are the primary decision makers regarding household water sources in many developing nations, but are often overlooked by researchers and organizations as primary water managers. This study took place in Pótam, Sonora, Mexico, during the summer of 2007, with a follow-up visit in February 2008. The study aimed at understand the human cycle of water by identifying potential exposure pathways for water contamination, as well as to understand the link between cultural beliefs, perceptions, and associated health issues. In total, sixty women were interviewed, as well as community elders and the Water Committee president. Discussions of household water use decisions, perceptions of disease causation, and treatment proved crucial in the discovery of potential pathways by which anthropogenic contaminants come into contact with the water cycle in Pótam. Most of the households (87%) believe their water sources are contaminated with biological and or chemical contaminants. Furthermore, of the sixty informants interviewed, seventy percent reported diarrhea as a common symptom. The majority of informants (76%) made a link between consumption of contaminated water and high rates of diarrhea. The study determined that the community is in need of outreach programs geared toward women as household water managers, independent lab analysis of water quality samples, and an epidemiological study to determine the causes for the most commonly reported illness and symptoms.     

Quantifying monthly water balance to estimate water deficit in Mayurakshi River basin of Eastern India

Environment, Development and Sustainability - Recorded seasonal variation and uneven distribution of rainfall is one of the major issues to the agrarian society and the domestic water users today....     

Risk assessment on disinfection by-products of drinking water of different water sources and disinfection processes

The occurrences of trihalomethanes (THMs) and haloacetics (HAAs) in the water supply in Beijing and Canada were investigated. The concentrations of THMs and HAAs in Beijing and Canada were below the maximum contaminant levels specified by the USEPA and WHO standards. The multi-pathway risk assessment (assessed through oral ingestion, dermal absorption and inhalation exposure to drinking water) was used to assess the cancer risk and the hazard index of THMs and HAAs from fifteen waterworks in Beijing, China and three treatment plants using different disinfection processes in Canada. Residents in Beijing and residents who were served by three treatment plants using different disinfection processes in Canada had a higher risk of cancer through oral ingestion than through the other two pathways. The cancer risk resulted from disinfection by-products (DBPs) was 8.50E-05(for males), 9.25E-05(for females) in Beijing, China, while it was 1.18E-04, 1.44E-04 in Canada. The risk was higher when water treatment plants used surface water source than when they used ground water source and mixture water source in Beijing. The risk showed different changes in three treatment plants using different disinfection processes in Canada. The lifetime cancer risk for THMs followed the order: Plant 2>Plant 1>Plant 3. And, the lifetime cancer risk for HAAs was: Plant 1>Plant 2>Plant 3.     

A commentary on recent water safety initiatives in the context of water utility risk management

Over the last decade, suppliers of drinking water have recognised the limitations of relying solely on end-product monitoring to ensure safe water quality and have sought to reinforce their approach by adopting preventative strategies where risks are proactively identified, assessed and managed. This is leading to the development of water safety plans; structured 'route maps' for managing risks to water supply, from catchment to consumer taps. This paper reviews the Hazard Analysis and Critical Control Point (HACCP) procedure on which many water safety plans are based and considers its appropriateness in the context of drinking water risk management. We examine water safety plans in a broad context, looking at a variety of monitoring, optimisation and risk management initiatives that can be taken to improve drinking water safety. These are cross-compared using a simple framework that facilitates an integrated approach to water safety. Finally, we look at how risk management practices are being integrated across water companies and how this is likely to affect the future development of water safety plans.     

Human health effects of residual carbon nanotubes and traditional water treatment chemicals in drinking water

The volume of industrial and domestic wastewater is increasing significantly year by year with the change in the lifestyle based on mass consumption and mass disposal brought about by the dramatic development of economies and industries. Therefore, effective advanced wastewater treatment is required because wastewater contains a variety of constituents such as particles, organic materials, and emulsion depending on the resource. However, residual chemicals that remain during the treatment of wastewaters form a variety of known and unknown by-products through reactions between the chemicals and some pollutants. Chronic exposure to these by-products or residual chemicals through the ingestion of drinking water, inhalation and dermal contact during regular indoor activities (e.g., showering, bathing, cooking) may pose cancer and non-cancer risks to human health. For example, residual aluminium salts in treated water may cause Alzheimer's disease (AD). As for carbon nanotubes (CNTs), despite their potential impacts on human health and the environment having been receiving more and more attention in the recent past, existing information on the toxicity of CNTs in drinking water is limited with many open questions. Furthermore, though general topics on the human health impacts of traditional water treatment chemicals have been studied, no comparative analysis has been done. Therefore, a qualitative comparison of the human health effects of both residual CNTs and traditional water treatment chemicals is given in this paper. In addition, it is also important to cover and compare the human health effects of CNTs to those of traditional water treatment chemicals together in one review because they are both used for water treatment and purification.     

Artificial wetlands and water quality improvement

This paper illustrates the role of plants to assist the treatment of water pollution in man-made wetlands in tropical and temperate climates. It also considers the potential for environmental education of these wetland systems. The management and natural treatment of pollution is described in the Mai Po Marshes, Hong Kong and a wetland in London which is also an important site for birds. The design of the Putrajaya Lake and Wetland system in Malaysia is compared with a constructed wetland and lake for the treatment of urban surface runoff in a new residential development in the United Kingdom. The benefits of these natural systems are discussed in the context of the global trend for introducing sustainable methods of environmental management and low cost pollution treatment systems.     

Removal of hydrocarbons from Nile water

The need to remove hydrocarbons from water supply sources raises questions on the efficiency of the present water treatment processes in removing hydrocarbons. Therefore, the effectiveness of physicochemical processes involving chlorination, chemical coagulation and sand filtration were investigated. The effect of variable filtration media was also examined. In addition, the use of an activated carbon column was considered, and the effect of different retention times was evaluated. Results of this study showed that chemical coagulation using alum and Nalco removed only 32% of the total hydrocarbons and 80% of turbidity. Use of sand and a mixture of anthracite and sand filters showed additional removal of hydrocarbons and turbidity during the continuous filtration process. Increasing the anthracite depth relative to the total effective filtration depth increases the efficiency of the filter. Adsorption on granular activated carbon was shown to be an effective means for the removal of hydrocarbons. Results obtained indicated that the carbon adsorption capacity increases linearly as the retention time increases.     

The transition in Dutch water management

Over the past decades, the Dutch people have been confronted with severe water-related problems, which are the result of an unsustainable water system, arising from human interventions in the physical infrastructure of the water system and the water management style. The claims of housing, industry, infrastructure and agriculture have resulted in increasing pressure on the water system. The continuous subsidence of soil and climate change has put pressure on the land. Hence, the nature and magnitude of water-related problems have changed. Longitudinal research of relevant national policy documents reveals that the water management regime has changed its water management style over the past 30 years from a technocratic scientific style towards an integral and participatory style. We have investigated if the historical development in Dutch Water management can be characterized as a transition. Based on longitudinal research through an integrated systems analysis, document research and expert interviews, we have reconstructed the historical narrative by using the transition concepts of multi-level and multi-phase. This research indicates that the shift in Dutch Water management can be characterized as a transition. This transition is currently in the take-off stage and near the acceleration stage. This is a crucial stage as long as the considerable gap between the strategic macro-vision and the practical implementation at the micro-level remains. As long as these levels are not compatible (modulation), the transition will not be completed successfully. Transition management as multi-level governance model should therefore be adopted to facilitate the modulation.     

Sustainability indicators of water sharing compacts

There is an increasing crisis of fresh water availability throughout the world. Sharing the available water resources in a sustainable manner among numerous stakeholders in the backdrop of this crisis is more challenging. Very often water conflicts are triggered out in this challenging scenario. These conflicts are sometimes reconciled with compacts on sharing. Water sharing compacts on both surface and aquifer resources are very common. Whether these compacts are founded on postulates of sustainability is the important question we want to investigate. Conflicts resurface when the sustainability of a compact is at stake. In this paper, we are reviewing three compacts on surface water sharing to understand their sustainability perspectives and how it has helped addressing conflicts. An introduction to various legal instruments promulgated aiming water conflict abatement is given first. Different types of water sharing agreements being signed in the current water management practice are also looked into. Theoretical background of sustainability analysis, both quantitative and qualitative, applicable in the case of water sharing models is then discussed. This is followed by specific case study analysis of three interstate water sharing agreements executed in basins of different agro-climatic regions across the world. It includes the Colorado basin (USA), Murray Darling basin (Australia) and the Parambikulam Aliyar Project (PAP) basins (India). Interstate water sharing agreement of these basins is critically examined and compared to comment on its sustainability perspective. The Murray Darling basin and its compact appear to be better in its overall considerations of sustainability. Compared to Colorado and Murray Darling, PAP requires major revisions in its sustainability context. E flows and stochastic modeling are the thrust areas of PAP that require major revision.     

Significant issues in water resources policy

The difficulties in resolving water resource policy questions are analogous in many ways to the difficulties in resolving energy policy questions — technical, legal, institutional and social. Federal involvement in water resources began in 1809 and continues to the present time. The most recent comprehensive study was the Second National Water Assessment by the U.S. Water Resources Council in 1979. Conclusions reached were that water quality and quantity and surface and ground water are artificial distinctions, that water policies should reflect national needs and priorities, that flood control must be accelerated and drinking water quality protected and that more decisions should be made at a local level while integrated into national planning and development. Though the study disaggregated the U.S. into 106 subregions, its projections of a single future rather than a range of futures gives an erroneous sense of predictability to the work. To help resolve the major problems, inadequate supply and contamination and flooding and erosion, ultrasophisticated mathematical models are widely utilized without sufficient verification. A more tractable approach for policy studies would be to use simplified semi-empirical models rather than first principle models. Possibly more important, policy resolution awaits social value resolution which means that the policies adopted must be flexible, incremental, and non-divisive.     

水权市场研究述评与中国特色水权市场研究展望

水权水市场改革是我国水资源管理改革的重要内容,也是当前我国资源环境研究领域的热点之一。我国水权市场尚未发育完成,水权交易还未成体系,更缺乏水权交易的制度体系和技术支撑。国内外的研究表明,有效运作的水权市场,需要具备产权明晰、计量监测技术支撑、监管制度完善等多方面的条件,同时也会受到交易成本、第三方效应、社会文化等多方面的影响;从已有的水权交易模型来看,国内学者基本上是沿用了西方发展起来的水权交易模型,很少考虑中国国情因素。总体来看,国内水权水市场研究目前存在三个方面的主要缺陷。第一,在水权市场发展的规律研究方面,过于强调市场的作用和市场制度本身,对水权市场运作的内在机制认识不足;第二,在水权市场的国际经验借鉴方面,过于强调个别国家的"先进经验",对水权市场发展的教训和伴随的问题认识不足;第三,在水权交易和市场制度建设过程中,过于强调理想意义上的自由市场模式,对国情条件的制约和中国特色的因素认识不足。当前亟需开展更为深入的研究,系统探索中国国情因素对水权市场构建的影响,重点揭示中国特色的水权市场制度体系特征,提出中国情境下的水权交易模式、交易规则、水权监管制度以及与国情条件相适应的水价政策。通过理论集成和知识创新,增进对中国特色水权市场制度的理解,为水资源管理体制改革和水资源的可持续利用提供研究支撑。     

Governing water in federal river basins

Regional Environmental Change -