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close this bookCentral Eurasian Water Crisis: Caspian, Aral, and Dead Seas (UNU, 1998, 203 pages)
close this folderPart I: introduction
close this folder3. Major environmental problems in world lakes
View the document(introductory text...)
View the documentDeclining water levels
View the documentRapid siltation
View the documentAcidification
View the documentThe progress of eutrophication
View the documentContamination with man-made toxics
View the documentThe collapse of aquatic ecosystems
View the documentAcknowledgements
View the documentReferences

The progress of eutrophication

Eutrophication is spreading, owing to the combined effects of such factors as industrialization, the urban concentration of populations, changing ways of life toward mass consumption and mass dumping, the increased application of fertilizers on cropfields, deforestation and other types of ecosystem disturbance in catchment areas, the submergence of terrestrial biomass caused by reservoir construction, aquaculture within lakes, and so on.

Eutrophication has been, and perhaps will continue to be, the most widespread type of environmental pollution of water bodies. It is expanding rapidly from industrialized or urban areas to rural areas, from small streams to larger rivers, from small lakes to larger lakes, and from inland waters to coastal marine waters. The current situation in some lakes of overpopulated areas is critical, because newly growing large cities have to depend for their water supply on hyper-trophic lake water filled with blooms of blue-green algae. Eco-technological measures are not effective enough to overcome the crisis in the short term, and large-scale environmental technology such as sewage treatment systems is too expensive to be easily adopted.