most information deals with Egypt; few studies have been done in Sudan, Ethiopia and Tanzania. Egypt is the most populous, agricultural and industrial country in the basin. Therefore, most sewage release to the river takes place in Lower Egypt. Lakes in northern Egypt are affected by drainage of polluted water and this affects the diversity of their fish, phytoplank-ton and other microorganisms. Nile pollutants are derived from sources such as industrial wastewater, oil pollution, municipal wastewater, agricultural drainage, and include natural cyanotoxins. In order to monitor pollutants, test organisms are needed in which these compounds can be traced at the tissue level. Various fish, shellfish, aquatic animals, aquatic plants and algae are used for this purpose.
