Abstract
The three main Nile Delta wetland ecosystems, Manzala, Burullus and Edku lagoons, are among the most ecologically important and productive habitats in Egypt. We studied the area degradation and the human health risks associated with trace metal accumulation in Tilapia zillii harvested from these lakes. The area of Manzala lagoon has shrunken from about 3035km(2) in 1800 to about 288km(2) in 2015, the area of Edku has shrunken from about 336km(2) in 1824 to about 18km(2) in 2014, and the area of Burullus has shrunken from about 1116km(2) in 1949 to about 546km(2) in 2014. This area degradation is attributed to drying for housing, land reclamation and fish farming. As a result, the concentration of pollutants and nutrients has subsequently increased, and large parts of the lakes have been overgrown with aquatic vegetation, which increased the rate of degradation and land transformation. Metal pollution was detected in water, sediment and edible fish harvested from the lakes. The hazard index, an indicator of human health risks associated with fish consumption, showed adverse health effects of zinc and lead metals for habitual fish consumers. The impact of the high dam on the lakes was discussed.