(Received October 7, 1984)

Increasing urbanization, industrialization and population growth in developing countries of the Third World will potentially increase the number of hypertrophic freshwater ecosystems unless suitable effluent and water quality standards are promulgated. Unchecked eutrophication, or enrichment, of freshwater with plant growth nutrients leads to hypertrophy. Hypertrophic systems are those which have been enriched to the point where massive algal and/or macrophyte populations appear and major changes in ecosystem structure occur. While these systems are highly productive they also tend to be ecologically unstable. Algal population collapses or huge oxygen demands from anaerobic hypolimnia at lake overturn can lead to whole lake anoxia. Hypertrophy can result in the servere impairment of water use, increased costs to provide potable water and cause major health problems.