You are viewing an archived web page, collected at the request of United Nations Educational, Scientific and Cultural Organization (UNESCO) using Archive-It. This page was captured on 10:12:10 Dec 29, 2015, and is part of the UNESCO collection. The information on this web page may be out of date. See All versions of this archived page.
Loading media information hide
Hydrology for the Environment, Life and Policy

  Home to Water Portal
  • Home to HELP
  • About HELP
  • News
  • You and HELP
  • Archives
  • HELP Action Areas
  • Water and Climate
  • Water and the Environment
  • Water Quality and Human Health
  • Water and Food
  • Water and Conflicts
  • Improving Communication

  • HELP Basins

  • Printer friendly version

  • Home > Water Quality and Human Health - Updated: 09-09-2004 7:43 am
    In 1992, 20 per cent of the world's population did not have a safe supply of water, and about 50 per cent of the population lacked adequate sanitation. A recent UN report states that more than 5 million people die annually from diseases caused by unsafe drinking water, and lack of sanitation and water for hygiene. According to the World Health Organisation, billions of people are at risk due to water-borne diseases.    

    Water quality and policy

    A wide range of chemical and biological agents adversely affects human health, and it is important to establish policies regarding activities that affect water quality and the health of downstream users. Legal and other vehicles, including the establishment of water-quality standards, need to be instituted, using an interdisciplinary and inter-institutional approach. The relative importance of chemical and biological agents varies according to differences in culture, and socio-economic and hydrological conditions. These differences need to be recognised in policies. For developed countries, key issues are micro-organic pollutants and micro-organisms, and appropriate policies need to be continually developed as we increase our understanding of the transport and fate of these constituents.

    The provision of potable water and sanitation are high priorities for developing countries, which require carefully crafted policies that accommodate human and environmental needs. Even in developed countries, particular subgroups may require special policy considerations.

    Water-quality laws (standards) for drinking water, recreational water and agriculture, as well as for wastewater effluents, are essential policy components for the protection of human health. Policies are required that not only support capacity building in water quality, but that also empower qualified individuals and organisations to implement appropriate action. Raising public awareness and participation are important elements of policies and actions for water quality and human health protection and management. Land-use and other policies (for example biotechnology and the release of genetically engineered organisms) need to consider the implications for water quality and human health. An important objective for HELP is to prevent narrow approaches to resolving water and health issues. These are cross-cutting issues, to be approached from several directions concurrently and in partnership.

    Water quality and management

    Water-quality management is becoming one of the most important aspects of water management. Some countries, particularly developing countries, focus only on point-source pollution issues because of their severe impact on the environment. In developed countries, where most point-source pollution has now been controlled, concern focuses on diffuse pollution and the hydro-ecology of water bodies. Management procedures are thus very different in different countries. More complete knowledge of the hydrological cycle will assist resource managers, because water is a primary conveyance for pollutants in the landscape. Evaporation increases concentrations, which can ultimately lead to poisoning of the landscape through land salinisation. In contrast, rainfall and associated runoff mobilise contaminants through and over the landscape, and the relative magnitude of contributions of water along the various hydrological pathways has major consequences for the resulting pollutant transport.

    The water environment capacity (WEC) is important for determining the limit for pollutant control. Knowing the WEC for different contaminants in varying environments will help managers prioritise source controls and determine appropriate best-management practices. The WEC has several features that are important for water-quality management. The WEC is a kind of resource, which is limited and can be consumed. Therefore, we need to clarify the maximal capacity for a body of water to receive a pollutant, so as to determinethe limit to which the water can be utilised. Parts of the WEC may be renewable, however, so that if the extent to which it used is soundly controlled we can achieve sustainable utilisation. When the WEC is destroyed, recovery is very difficult.

    Diffuse pollution is more common and severe than point-source pollution, and more challenging to manage. Diffuse pollution originates from extensive areas that produce soluble or solid pollutants. When these pollutants enter water bodies, such as rivers, lakes and reservoirs, water pollution and eutrophication can be induced. The main sources are normally soil erosion, applications of pesticide, chemical fertiliser and animal manure to farmland, and surface runoff from urban areas. Diffuse pollution is thus acomplex, random process. Even more alarmingly, we do not know the transit and residence times of contaminants in sub-surface water to be able to advise water managers on changes in water-land management policy. The management of diffuse pollution will bean important aspect of HELP.

    Water for human health is another important aspect that should be adequately emphasized in water quality management. Drinking water and water for sanitation account for small proportion of the total water consumed by mankind. However, it is this water that is vital to human health, and is the component which causes or potentially causes water-related diseases through unsafe drinking water and skin-contact with contaminated water.
    The water for drinking and sanitation is either abstracted from surface water or underground water. Surface water sources need to take into account the effect of the discharge and emissions upstream. Underground water is also a very important water source for drinking and sanitation in many countries, especially the countries in arid and semi-arid land. Therefore, the key challenge in water quality management is to take appropriate measures to prevent, control and reduce the underground water pollution and to mitigate the impact of pollution (including the transboundary impact) on drinking water and water for sanitation.

    We know that integrated catchment management is an effective way to manage both water resources and water quality. Several institutions have recently been established to manage international river basins according to signed agreements. Examples are the Mekong River Commission, the International Commission for the Protection of the Danube, the International Commission for the Protection of the Meuse and the International Commission for the Protection of the Scheldt. The provisions of the agreements define the powers and functions of such committees. Their main tasks include harmonising actions between users of the riparian zone, establishing unified monitoring systems, information exchange and ensuring that the participants follow the agreement. The convention or agreement is thus a precondition of the establishment of any such unified institution for international river-basin protection.

    Domestic catchment institutions have been established for a long time, with successful examples in some developed countries, such as the USA, France and the UK. The experience of these institutions is that when catchments are separately managed by several independent bodies, the environment quality tends to degrade. When the catchment is managed as a unit, the maximum potential of multiple uses and economy can be achieved. At the same time such institutions can co-ordinate the conflicts between different tributaries, reaches and sectors.No one generalised model to be applied to all catchments, because the form, structure and function of such institutions depend on local conditions. The power and function of such integrated management may include water resources management, water pollution control, fisheries, flood protection, soil conservation, hydro-ecology and the preservation of water bodies, and collection of charges.

    Water-quality management procedures lay the foundation for water-quality management in implementing related lawsand policies. Each country has drawn up its own procedures. These procedures can apply to water pollution control of existing projects, proposed projects, pollutants, or the protection of the hydro-ecology and the water environment. While the procedures will be different in each country because of different environmental conditions, they should all:
  • formulate unified protection planning;
  • implement an integrated monitoring programme;
  • use GIS to assist in decision making;
  • focus on hydro-ecological recovery;
  • identify links between water quality and human health;
  • promote the mutual understanding, information exchange, and participation of institutions and the public at all levels.

  • Many countries do not plan for water environment protection uniformly for each catchment. Planning is either particular to individual catchments or regional, only applying to some sectors or sub-areas of the catchment. Some countries have constituted integrated planning, but lack an integrated evaluation of the impacts of water resources fluctuations (due to climatic variability) on water quality. In addition, the legal, institutional issues and the participation of the public are not emphasised. It is therefore very important to formulate integrated plans for water environment protection in water environment management, according to the present conditions and future tendency of each catchment, taking into consideration the harmonisation of the economy, society and environmental development.

    The hydrological science contribution

    The main scientific objective is to develop the necessary integrated view of how catchments work, in order to understand the relations between water quality and water quantity at variable spatial and temporal scales. We have tounderstand how water quality is affected by varying land uses and management approaches – that is, to understand the basic evolution of water quality. So far, there has been an inadequate research effort in combined process hydrology and water quality processes. Our understanding of processes linked with contaminant transfer and temporary adsorption (or absorption) through the land system – before entry into organised surface drainage – is extremely poor. With understanding, it will be possible to evaluate the cause-and-effect relationships between physical, chemical, and biological processes, for example between hydrology and pathogens, or between hydrochemistry and toxin-producing species.

    To meet the above objective, the first priority is to establish appropriate water-quality monitoring programmes.

     ID: 1320 | guest (Read) © 2004 - UNESCO - Contact