首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 625 毫秒
1.
Surveillance systems for foodborne disease vary in capacity by country, especially for marine-related illnesses. Generally, the more developed the country is, the more funding that is put into its surveillance programs, but no country has an outstanding system that could serve as a model for all others. An additional problem is lack of consistency. Approaches to surveillance and available resources change over time, so that apparent trends may reflect more of an administrative function. Most countries have some passive system that allows data on foodborne illnesses to be sent to centralized authorities where summaries are generated. However, these depend on the uneven quality of the source data that vary according to the resources allocated at the local level. Active surveillance systems collect data targeted to answer specific epidemiological questions more efficiently, but at such a high cost that most countries do not have the resources, except on a occasional basis. There is also the issue of what to do with the collected data. There has to be a conscious effort to translate the problems identified from the surveillance programs to consider strategies for prevention and control of foodborne disease. Otherwise, there is little value in having these kinds of monitoring programs. Another problem is lack of coordination in surveillance systems between most countries, so that information can be rapidly and efficiently shared. That being said, surveillance over the years had generated much interesting information on how disease agents are transmitted through the food supply, and where contamination and growth by pathogens in the food production and preparation chain typically occur. In addition, attempts are being made to create regional networks in different parts of the world usually initiated by organizations like WHO and PAHO. The kinds of information collected and programs being introduced are discussed in examples taken from both the developed and less developed world, followed by a series of recommendations for improving surveillance on a global basis. A recent burden in the surveillance system is the potential for a deliberate attack on the food supply with agents not usually involved with foodborne illness. At least in the US, a major concern is for the rapid detection and containment of a massive contamination of the food supply.  相似文献   

2.
For over centuries developments in food production and new food safety management systems in most developed countries have been perceived by many to be efficient in the prevention of food-borne disease. Nevertheless a number of problems remain dominant, one of these being the high level of food-borne microbiological disease which seems, for some pathogens, to have increased over the last decades. The development of an interdisciplinary approach with direct interaction between surveillance and risk analysis systems is described as a potential basis for improved prevention of food-borne disease. Quantitative microbiological risk assessment is a relatively new scientific approach, able to link data from food within the entire food chain and the various data on human disease to provide a clear estimation of risk. Today food safety is one of the WHOs top eleven priorities; the Organization calls for more systematic and aggressive steps to be taken to reduce significantly the risk of microbiological food-borne diseases. Dealing with this challenge is one of the major challenges for the 21st century in regard to food safety, implying a significant re-direction of food microbiology efforts in many parts of the world.  相似文献   

3.
The increasing drought due to climate change poses a threat to issues such as safe and accessible drinking water, food safety, and protection from diseases. The provision of water supply is vital for agricultural and livestock activities, which are commonly practiced around natural ore deposits. Examining traditional “irrigation water quality” methods alone is insufficient; investigating potentially toxic metal content in the region's waters is vital, especially around metallic ore deposits. This study focused on the Kiraz district in Turkey, known for its agricultural activities, to assess the impact of geogenic water pollution on irrigation water quality and its implications for food safety and human health. Geology determines nutrient availability, water resources, and land suitability for agriculture. Conventional irrigation water quality parameters indicate groundwater suitability for irrigation in the study area, considering Na%, sodium adsorption ratio, residual sodium carbonate, permeability index, Kelly ratio, magnesium hazard, and potential salinity. However, when examining the potential toxic metal content in the region, it was determined that the values of Al ranged from 96 to 8676 ppb, Ni values ranged from 27 to 360 ppb, and Sb concentrations varied between 9 and 53 432 ppb. Utilizing geogenically contaminated water for irrigation and its indiscriminate use in livestock, dairy, and food industries can lead to foodborne illnesses (cancer, endocrine disruptors, tuberculosis, antimony spots, thyroid tumors, goiter, neurologic and cardiovascular diseases) that endanger human health. The use of low-quality water throughout the agricultural sector and food production chain increases food safety risks.  相似文献   

4.
Water resources and food program   总被引:1,自引:0,他引:1  
Data on the volumes of renewable water resources and the specific dependable water supply are given for countries with the least water resources available. Data on the current volumes of water resources withdrawal, irrigated land area, and the population size in largest world countries are given. Measures taken by various countries with the aim to enhance water resources availability for agriculture are described. The further increase in the area of arable and irrigated lands, with the current technologies still in use in the agriculture, is shown to be inadmissible. The role of reclamation in the ensuring of food safety in Russia is demonstrated.  相似文献   

5.
Modelling blue and green water resources availability in Iran   总被引:7,自引:0,他引:7  
Knowledge of the internal renewable water resources of a country is strategic information which is needed for long‐term planning of a nation's water and food security, among many other needs. New modelling tools allow this quantification with high spatial and temporal resolution. In this study we used the program Soil and Water Assessment Tool (SWAT) in combination with the Sequential Uncertainty Fitting program (SUFI‐2) to calibrate and validate a hydrologic model of Iran based on river discharges and wheat yield, taking into consideration dam operations and irrigation practices. Uncertainty analyses were also performed to assess the model performance. The results were quite satisfactory for most of the rivers across the country. We quantified all components of the water balance including blue water flow (water yield plus deep aquifer recharge), green water flow (actual and potential evapotranspiration) and green water storage (soil moisture) at sub‐basin level with monthly time‐steps. The spatially aggregated water resources and simulated yield compared well with the existing data. The study period was 1990–2002 for calibration and 1980–1989 for validation. The results show that irrigation practices have a significant impact on the water balances of the provinces with irrigated agriculture. Concerning the staple food crop in the country, 55% of irrigated wheat and 57% of rain‐fed wheat are produced every year in water‐scarce regions. The vulnerable situation of water resources availability has serious implications for the country's food security, and the looming impact of climate change could only worsen the situation. This study provides a strong basis for further studies concerning the water and food security and the water resources management strategies in the country and a unified approach for the analysis of blue and green water in other arid and semi‐arid countries. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

6.
Urban areas of developing countries are facing increasing water scarcity and it is possible that this problem may be further aggravated due to rapid changes in the hydro-environment at different scales, like those of climate and land-cover. Due to water scarcity and limitations to the development of new water resources, it is prudent to shift from the traditional ‘supply based management’ to a ‘demand management’ paradigm. Demand management focuses on measures that make better and more efficient use of limited supplies, often at a level significantly below standard service levels. This paper particularly focuses on the intermittent water supplies in the cities of developing countries. Intermittent water supplies need to be adopted due to water scarcity and if not planned properly, results in inequities in water deliveries to consumers and poor levels of service. It is therefore important to recognise these realities when designing and operating such networks.The standard tools available for design of water supply systems often assume a continuous, unlimited supply and the supplied water amount is limited only be the demand, making them unsuitable for designing intermittent supplies that are governed by severely limited water availability. This paper presents details of new guidelines developed for the design and control of intermittent water distribution systems in developing countries. These include a modified network analysis simulation coupled with an optimal design tool. The guidelines are driven by a modified set of design objectives to be met at least cost. These objectives are equity in supply and people driven levels of service (PDLS) expressed in terms of four design parameters namely, duration of the supply; timings of the supply; pressure at the outlet (or flow-rate at outlet); and others such as the type of connection required and the locations of connections (in particular for standpipes). All the four parameters are calculated using methods and techniques that recognise the relationship between outflow at a water connection and the pressure experienced at that connection. The paper presents a case study where it is demonstrated that the new guidelines can provide an equitable and acceptable level of service throughout the design horizon of the project.  相似文献   

7.
Water scarcity has been an important issue for many countries. The water scarcity is still growing in some region but may be exacerbated by recent climate change. Both international and domestic reports classified Korea into water scarcity country on the basis of Falkenmark indicator. Korea, however, missed the concept of green water in calculating their annual renewable water resources per capita and erroneously defined them as water scarcity country. A new calculation shows that Korea has no water scarcity with 1712 m3 of annual renewable water resource per capita. Wrong information in Korea was badly used for political propagation and private purpose. This may be happening to other countries. Water resources experts need to include the concept of green water in reanalyzing the annual renewable water resources to provide decision-makers with acceptable guideline. Decision should be made with more reliable ground.  相似文献   

8.
Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge – one that affects the lives of one fifth of humanity.  相似文献   

9.
《Water Policy》1998,1(3):267-282
In 1994 the UN Commission for Sustainable Development, CSD, the commission to ensure follow-up of the UNCED, decided that a Comprehensive Assessment of the Freshwater Resources of the World should be undertaken by relevant UN-agencies in cooperation with other relevant organisations represented by the Stockholm Environment Institute. The Assessment, CFWA, that was presented to the CSD and to the UN General Assembly Special Session 1997, served as an ‘alarm clock’ at the highest political level. It demonstrated that many challenges that lays ahead are related to freshwater resources and their managing, including water for global food production and security aspects. The CFWA reiterated the importance of socio-economic links, something that was emphasised in the outcome of the Dublin Conference 1992, where water to be regarded as an economic good is an important principle. The CFWA defined water stress as high withdrawal of the available water resources. Countries with high water stress are using more than 40% of their resources. The CFWA also identified economic capability to coop with water stress by using the World Bank per-capita income index. Four countries were defined (low stress-high income, low stress-low income, high stress-high income and high stress-low income) where different strategies should be applied. The CFWA used scenarios to describe the situation 2025 ‘what if…’. Common strategies for all countries should include the application of an integrated approach where water planning is to be included in all socio-economic planning, and demand management, where demands need to be adjusted to existing supply, by reuse of water etc. The need for partnership and cooperation in implementation is emphasised.  相似文献   

10.
Drought in Africa has been extensively researched, particularly from meteorological, agricultural, and food security perspectives. However, the impact of drought on water security, particularly ground water dependent rural water supplies, has received much less attention. Policy responses have concentrated on food needs, and it has often been difficult to mobilize resources for water interventions, despite evidence that access to safe water is a serious and interrelated concern. Studies carried out in Ghana, Malawi, South Africa, and Ethiopia highlight how rural livelihoods are affected by seasonal stress and longer-term drought. Declining access to food and water is a common and interrelated problem. Although ground water plays a vital role in buffering the effects of rainfall variability, water shortages and difficulties in accessing water that is available can affect domestic and productive water uses, with knock-on effects on food consumption and production. Total depletion of available ground water resources is rarely the main concern. A more common scenario is a spiral of water insecurity as shallow water sources fail, additional demands are put on remaining sources, and mechanical failures increase. These problems can be planned for within normal development programs. Water security mapping can help identify vulnerable areas, and changes to monitoring systems can ensure early detection of problems. Above all, increasing the coverage of ground water–based rural water supplies, and ensuring that the design and siting of water points is informed by an understanding of hydrogeological conditions and user demand, can significantly increase the resilience of rural communities to climate variability.  相似文献   

11.
The current practice of water resources use in irrigated agriculture in the Republic of Azerbaijan has some specific features and causes problems in the management of irrigation systems of different levels, associated with the existing land use and cropping patterns in the country. This article substantiates the need to implement a system of measures for improving water resources management in irrigation aimed to prevent the further depletion of their reserves through modernization of irrigation–reclamation systems and improvement of agricultural practices. The article proposes principles for protection of water resources and measures to mitigate the aftereffects of intense irrigation under anticipated increase in the internal consumption of freshwater and a decrease in transboundary river inflow into the Republic of Azerbaijan in the context of increasing water intake in the countries in Kura–Aras basin and global climate changes.  相似文献   

12.
王加虎  郝振纯  姜彤  施雅风  曾涛 《湖泊科学》2003,15(Z1):277-288
本文以联合国粮农组织推荐的改进彭曼-蒙特斯公式为基础,通过日气温计算年蒸发总量并验证,用典型年预测全流域年平均气温增加时,参照蒸散发的变化情况。研究表明:长江流域的年蒸发量将随年平均气温的上升而增加;上游增幅大于中下游,各月增幅相近;气温增幅的年内分布不容忽视,考虑到年内气温不等量增长后的计算结果相对更为合理。研究结果表明:当流域年平均气温升高1℃时,流域上、中下游参照蒸散发分别将增加5%和4%.研究中未考虑气温日较差的变化.  相似文献   

13.
To increase the resilience of regional water supply systems in South Africa in the face of anticipated climatic changes and a constant increase in water demand, water supply sources require diversification. Many water-stressed metropolitan regions in South Africa depend largely on surface water to cover their water demand. While climatic and river discharge data is widely available in these regions, information on groundwater resources – which could support supply source diversification – is scarce. Groundwater recharge is a key parameter that is used to estimate groundwater amounts that can be sustainably exploited at a sub-watershed level. Therefore, the objective of this study was to develop a reliable hydrological modelling routine that enables the assessment of regional spatio-temporal variations of groundwater recharge to discern the most promising areas for groundwater development. Accordingly, we present a semi-distributed hydrological modelling approach that incorporates water balance routines coupled with baseflow modelling techniques to yield spatio-temporal variations of groundwater recharge on a regional level. The approach is demonstrated for the actively managed catchment areas of the Amathole Water Supply System situated in a semi-arid part of the Eastern Cape of South Africa. In the investigated study area, annual groundwater recharge exhibits a high spatio-temporal heterogeneity and is estimated to vary between ~0.5% and 8% of annual rainfall. Despite some uncertainties induced by limited data availability, calibration and validation of the model were found to be satisfactory and yielded model results similar to (point) data of annual groundwater recharge reported in earlier studies. Our approach is therefore found to derive crucial information for efficiently targeting more detailed groundwater exploration studies and could work as a blueprint for orientating groundwater potential exploration in similar environments.  相似文献   

14.
《Water Policy》1998,1(4):421-436
Against the background of a Mar del Plata 20 year Anniversary Seminar, a global overview of the current water resources dilemma is presented. Three main security threats are highlighted that should be reason for strong concern: continued water quality degradation, slowly reducing the use options of accessible water; food insecurity risk, introducing a water ethics perspective into recommended considerations of water economy; and a growing river depletion in response to intensified food production in the tropics and subtropics. Through a backcasting approach to a more sustainable world by 2025, a set of crucial policy measures are identified. The low coping capability typical for most rapidly growing developing countries is considered a massive challenge to be urgently addressed.  相似文献   

15.
《Water Policy》2001,3(1):47-59
Eureau is the Union of most National Associations of Water Suppliers and Wastewater Services in Europe. Most northern Eureau countries have abundant water resources. There, the need for extra supply through the reuse of treated wastewater is not a priority, but the protection of the receiving environment is considered important. The situation is different in the southern Eureau countries, where the additional resources brought by wastewater reuse can bring significant advantages to agriculture (e.g. crop irrigation) and tourism (e.g. golf course irrigation). There, wastewater is reused but under very diverse regulatory environments. Therefore, considering its various potential benefits (protection of water resources, prevention of coastal pollution, recovery of nutrients for agriculture, augmentation of river flow, savings in wastewater treatment, groundwater recharge, and sustainability of water resource management, etc.), wastewater reclamation and reuse can be applied to the advantage of both northern and southern Eureau countries. In order to take advantage of its full potential, Eureau would like to become involved in setting up international best practices and guidelines related to the reuse of treated wastewater. Such criteria and/or guidelines should contribute to a better management of water resources, a better protection of public health and of the environment and to a more sustainable development. Reclaimed wastewater is a reliable source of water that must be taken into account in formulating a sustainable water policy. To encourage wastewater reclamation and reuse in all Eureau countries and to establish its safe practice, European guidelines for most applications must be developed.  相似文献   

16.
Water resources for agricultural development and landscape enhancement in Kuwait are very scarce; the quality is saline (brackish), and the soil texture is sandy, incapable of holding nutrients and moisture. Most of the rainfall in Kuwait either evaporates due to the high temperatures or percolates through the soil. The rainfall is not sufficient to recharge the underground water supply. A variety of alternative water sources have been studied, including seawater desalination and wastewater treatment. Wastewater treatment proved to be convenient due to the relatively low salinity detected in the treated water. Furthermore, the amount of wastewater is expected to increase as more residential areas are connected to the sewage system as the population increases.

The development of a greenery plan for Kuwait requires intensive water management. This goal can be achieved through manpower training in landscape development, selection of plants tolerant to arid environments, usage of appropriate irrigation and drainage systems, promotion of greenery programs within public and the governmental agencies for their direct participation in urban area beautification, and extension of wastewater treatment techniques.  相似文献   


17.
Multiple stresses are putting great pressure on water resources systems. Population growth, climate change, prosperity, energy production, food crisis, and water governance are among the factors straining water resources. Decision makers from rich to poor countries and from commercial to non-governmental organisations are struggling to devise schemes to adapt to these stressed water conditions. Better efficiency for water resources systems, and particularly irrigation systems, is recommended as one of the most important responses to climate change, unsustainable development, and water shortage. However, using certain efficiencies such as Classical Efficiency caused systems not to perform according to decision makers?? objectives. Effective Efficiency is a robust composite indicator that includes in its formulation both a flow weight, taking into account the leaching fraction, and reuse of return flows. Classical Efficiency is defined as the percentage of the diversion consumed beneficially, such as by crop evapotranspiration. Effective Efficiency, on the other hand, is defined as the ratio of beneficial consumptive use to total consumption, expressed as a percentage. In this paper, a normalised and non-dimensional form of Effective Efficiency is developed and necessary constraints for its successful application are explained. These constraints express water balance, flow weights and their thresholds, water reuse, and total consumptive use. Basic guidelines are proposed for better decision making in determining possible interventions for improving Effective Efficiency. This is done by analysing its domain through analytical and graphical methods. Three real cases are considered, namely, Imperial Irrigation District and Grand Valley irrigation systems in the United States and Nile Valley in upper Egypt. Three-dimensional sensitivity analysis is performed on Effective Efficiency and its variables using the three cases. This leads to an examination of the validity of the analysis and to suggestions for better intervention options. Meanwhile, it is also shown why Classical Efficiency should be used with care.  相似文献   

18.
Chlorinated‐solvent compounds are among the most common groundwater contaminants in the United States. A majority of the many sites contaminated by chlorinated‐solvent compounds are located in metropolitan areas, and most such areas have one or more chlorinated‐solvent contaminated sites. Thus, contamination of groundwater by chlorinated‐solvent compounds may pose a potential risk to the sustainability of potable water supplies for many metropolitan areas. The impact of chlorinated‐solvent sites on metropolitan water resources was assessed for Tucson, Arizona, by comparing the aggregate volume of extracted groundwater for all pump‐and‐treat systems associated with contaminated sites in the region to the total regional groundwater withdrawal. The analysis revealed that the aggregate volume of groundwater withdrawn for the pump‐and‐treat systems operating in Tucson, all of which are located at chlorinated‐solvent contaminated sites, was 20% of the total groundwater withdrawal in the city for the study period. The treated groundwater was used primarily for direct delivery to local water supply systems or for reinjection as part of the pump‐and‐treat system. The volume of the treated groundwater used for potable water represented approximately 13% of the total potable water supply sourced from groundwater, and approximately 6% of the total potable water supply. This case study illustrates the significant impact chlorinated‐solvent contaminated sites can have on groundwater resources and regional potable water supplies.  相似文献   

19.
《Water Policy》2001,3(5):425-448
Worldwide water resources are not uniformly distributed and generally scarce in arid and semi-arid zones such as the Middle East. Lebanon, which is located along the Mediterranean shores of the Middle East, remains blessed with relatively more water in comparison to its neighboring countries. Increased pressure on its water resources requires the formulation and implementation of a comprehensive management plan and strategic policies to pre-empt potential future water shortages. This paper examines existing water laws and regulations under the current institutional framework in Lebanon. Developmental policies and management strategies to address the potential water supply demand imbalance and meet future challenges are presented in the light of existing legal and regulatory constraints and institutional capacities.  相似文献   

20.
滕吉文  杨辉 《地球物理学报》2013,56(12):4164-4188
在当今全球各国对油、气能源的需求和我国在工业化进程中油气能源十分紧缺的前提下,共享世界油、气能源的同时,必须立足于本土,迅速建立起安全、稳定,且可保证持续供给的油、气能源战略后备基地.油、气田勘探和开采中,尚存在着大于或远大于通常所规范的油、气生成稳定温度和深度限定,而向深部勘察油、气的理念又受到传统油、气成因理论的严峻挑战.为此,近些年来,通过对沉积建造、结晶基底,深部油气生成的物理(主指温度、压力)条件、物源和聚集储存空间的研究,提出:①沉积盆地中存在双相(陆相+海相)沉积建造,而基底则分为中、新生代沉积基底和古老的变质岩结晶基底,即双层基底;②地壳深部介质的物理-化学属性和变质岩及存储空间为油、气的生成和聚集提供了物质基础;③厘定了在有机成因主导下,油、气混合成因(有机+无机)的新理念;④第二深度空间(5000~10000 m)的油、气探查和开发将必是未来深部发现大型和超大型油、气田和深化研究的必然轨迹.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号