Water : Glossary

There are 59 documents in this section.

  • Water withdrawal

    8 December 2000

    Removal of freshwater for human use from any natural source or reservoir, such as a lake, river or aquifer. If not consumed, the water may return to the environment and can be used again.

  • Water scarcity

    8 December 2000

    According to a growing consensus among hydrologists, a country faces water scarcity when its annual supply of renewable freshwater is less than 1,000 cubic meters per person. Such countries can expect to experience chronic and widespread shortages of water that hinder their development.

  • Water stress

    8 December 2000

    A country faces water stress when its annual supply of renewable freshwater is between 1,000 and 1,700 cubic meters per person. Such countries can expect to experience temporary or limited water shortages.

  • Pathogen

    22 August 2000

    Agent causing disease.

  • Pesticides

    22 August 2000

    Chemical products designed to kill or restrict the development of pests. They include fungicides, herbicides and insecticides. Pesticides range from relatively simple elements such as sulphur (S) to complex chemical compounds such as chlorinated hydrocarbons and may be broad-spectrum or narrow-spectrum agents. Pesticides also vary in their persistence in the environment, and in general, the longer they remain chemically stable the greater is their potential for environmental damage. The use of pesticides has undoubtedly benefited society, by preventing disease and improving the food supply. At the same time, ignorance of the environmental impact of pesticides, the indiscriminate use of certain products and inadequate control of the production and use of pesticides has created problems for wildlife and natural vegetation and has threatened human health.

  • Water-washed diseases

    22 August 2000

    Diseases spread from one person to another due to inadequate supplies of water for personal hygiene. These include infections of the skin and eyes (e.g. trachoma) and infections carried by lice, e.g. louse-borne epidemic typhus.

  • WHO (World Health Organisation)

    22 August 2000

    A UN agency created in 1948 to deal with global health issues and to achieve as high a level of physical, mental and social well-being as possible for peoples of the world. It is involved in a variety of environemental studies, including the impact of climate change and ozone depletion on health, in conjunction with other agencies such as the World Meteorological Organisation (WMO) and the United Nations Environment Program(UNEP).

  • Cholera

    21 August 2000

    A bacterial disease caused by drinking water contaminated by sewage or eating food that has not been washed or is inadequately cooked. It is common in areas where the growth in population has outstripped the development of facilities for providing clean water or disposing of sewage. The problem is most severe in warm climates where high temperatures encourage the growth of the cholera bacteria.

  • Ecological balance

    21 August 2000

    Stability in an ecosystem achieved through the development of equilibrium among its various components. This does not imply that the community is static. It is subject to natural variations associated with ecological succession and other influences such as fire, disease and climate change, but the system is normally sufficiently elastic to make the necessary adjustments without major displacement of the balance. Human intervention that includes the introduction or removal of plants and animals, pollution of the environment and destruction of habitat is now a main cause of imbalance in many ecosystems.