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For any form of publication, please include the link to this page and give the cartographer/designer credit (in this case Philippe Rekacewicz, UNEP/GRID-Arendal)
Global Environment Monitoring Systems (GEMS), Freshwater Quality Programme, United Nations Environment Programme (UNEP), 2001
Uploaded on Saturday 25 Feb 2012
Regional trends in biological oxygen demand
Philippe Rekacewicz, UNEP/GRID-Arendal
The graphic is a global comparison of the biological oxygen demand measured in milligrams per litre. It covers the years from 1976 - 2000. The biological oxygen demand refers to the amount of oxygen required by aerobic microorganisms to decompose the organic matter in a sample of water, such as that polluted by sewage.