Environmental Damage Caused by Wastewater Discharge into the Lake Manzala in Egypt

Abstract

Lake Manzala is a brackish lake in northeastern Egypt on the Nile Delta. It is the largest of the northern Delta lakes of Egypt. The Lake is exposed to high inputs of pollutants from industrial, domestic, and agricultural sources. Climate gases and large amounts of particulate matter, nutrients, bacteria, heavy metals, and toxic organics are transported to the Lake through the wastewater discharge. Water samples were collected and subjected to physicochemical analysis and microbiological study. Results have shown great changes in physical and chemical properties of water including: temperature (13.5°C in winter-32°C in summer), pH (7.8-9.2), dissolved oxygen (2.5-12.8 mgl-1), total dissolved solids (1033-43406 mgl-1), total suspended solids (120-387 mgl-1), ammonia (2.5-32.3 mgl-1), nitrite (0-0.076 mgl-1), nitrate (0.01-7.88 mgl-1), phosphate (0.26-2.37 mgl-1), Fe (0.01-0.63 mgl-1), Zn (0-0.35 mgl-1), Cu (0.01-0.91 mgl-1), Cn (0.002-0.029 mgl-1) and Ni (0-0.002 mgl-1). Results, also, showed a quit great density of total viable bacterial count and indicator organisms including total Coli forms, fecal coli forms, Aeromonas spp., Staphylococcus spp. and Vibrio spp. It is concluded that water in Lake Manzala is highly damaged and the phenomena need more attention in order to reduce the pollution load that reaches the Mediterranean Sea.