Water, health and ecosystems

Most of the earth's surface is covered by water, and most of the human body is composed of water –two facts illustrating the critical linkages between water, health and ecosystems.

Global freshwater consumption rose six-fold between 1900 and 1995 – at more than twice the rate of population growth(1). Yet for many of the world’s poor, one of the greatest environmental threats to health remains lack of access to safe water and sanitation, which results in an estimated 1.7 million deaths every year (2).

Other key determinants of water-related disease and death include: poor access to sufficient quantities of water; and contact with contaminated water sources. About one-third of the world's population lives in countries with moderate to high water stress. Two out of every three persons on the globe may be living in water-stressed conditions by the year 2025, if present global consumption patterns continue(1).

Significant impacts on freshwater ecosystems have resulted from the elimination of marshes and wetlands; the diversion of surface water or alteration of flows; increased exploitation of underground aquifers; and contamination of water with industrial and human wastes. The absolute quantity and the diversity of pollutants reaching freshwater systems have increased since the 1970s, and include not only organic materials, but also heavy metals, and thousands of man-made chemicals, such as fertilizers and pesticides. These contaminants have impacts on health as well as environment.

Action on solutions

An ecosystem approach: Natural ecosystems have intricate and resilient mechanisms to filter and replenish fresh water resources, as well as to maintain marine environments, which are equally vital to health. An 'ecosystem approach' recognizes and ascribes value, including economic value, to the 'services' such ecosystems provide, and ensures their sustainability, through modern management regimes.

Integrated water resource management: Different users within a watershed are interdependent; therefore, integrated water resource management is essential. Upstream uses of water impact the potential of downstream users to meet their needs. Land use, agricultural patterns, and industrial development all affect water resources. A wide range of sectors, e.g., agriculture, energy, industry, fisheries, tourism, local government all must plan and coordinate strategies on the full range of developments that affect ecosystems, natural hydrology, and water consumption – with reference to expert advice and guidance of health and environment sectors.

Protecting water from contamination from household to global level: Careful disposal of waste and protection of health from contaminated water sources is a vital principle – from the personal to the international level. It includes simple hygiene tactics like good handwashing practice and safe filtration/storage of household water resources; move onto local and municipal sanitation and waste disposal systems; and also include global regimes/conventions to protect both fresh and marine water sources from transboundary waste, unsustainable resource use, and contamination. Development and implementation of water quality standards, monitoring of water quality/water-related disease indicators, are critical to protection of water sources.

COASTAL ECOSYTEMS: A SPECIAL FOCUS

More than one-third of the world's population lives within 100 kilometer of a sea shore. Coastal ecosystems include features such as wetlands, estuaries, mangroves and coral reefs – all of which provide 'services' vital to human health and well-being. Those range from the natural filtration of freshwater sources in wetlands and forests; provision of habitats for fish and other food sources to spawn and develop; provision of livelihoods and recreational sites; and provision of coastal barriers against sea level fluctuation(3). Unsustainable development of aquaculture and tourism, transport and industrial facilities, and even dams upstream, can irreversibly diminish vital coastal ecosystem services to human health. The health and environment linkages of coastal ecosystems is a special focus of this Water, health and ecosystems section.

TopFoto.co.uk; UNEP; UNEP/Nuntawan Silp

Links to resources

Web accessible directories

General directory of web-accessible links on water resources

Links to water-related web portals, programmes and publications of the United Nations Environment Programme, World Health Organization, and other United Nations agencies are provided in Section 9 of the directory, while links to NGO, IGO and other water-related networks are found in Section 10. Both Section 9 and 10 offer links to a range of web-based meta-networks and meta-data bases, providing access to an even wider range of resources relevant to sustainable management of water resources, environment and health.

Topic index

References

• The state of the environment; freshwater. GEO-2000: Global Environment Outlook. Nairobi, United Nations Environment Programme, 1999.
• WHO, ed. The World Health Report 2002 : Reducing Risks, Promoting Healthy Life. Geneva, World Health Organization, 2002.
• Marine and coastal areas - state of the environment. GEO-2000 - Global Environment Outlook. Nairobi, United Nations Environment Programme, 1999.