The impact of water pollution on White Nile Water quality and fisheries at Khartoum state

Abstract

Abstract , A ' This study was carried out during February 2009-August 2010 to investigate the impacts of sewage and industrial disposal from Elauzozab musruf into the White Nile around Khartoum on water quality, planktonic community and accumulationvlevels of Cd and Pb in fish (Orechromis niloticus). ' ' Samples-of water and plankton were taken monthly from four sites: J ebel Aulia (upstream),Al musraf, Elauzozab (disposal site), Almogran (downstream). _ Samples of water -for'physical and chemical analysis, Gills of fish (Orechromis nil0ticus)_~were examined for accumulation level of Cd and Pb as biological indicators of water pollution. The result revealed: ‘. . ' i At the disposal site and downstream sewage effluent increased conductivity (sss umho), TDS (492 mg/L), TSS (137 mg/L), BOD (30 mg/L), COD (56 mg/L), P04-P (0.46mg/L), NO;-N (l2mg/L), Cf! (0.54mg/L), Cd= (o.s6 mg/L), Pb = (0.45 mg/L) and depleted dissolved oxygen (4_mg/L). The maximum planktonic growth occurred in winter 2010 whereas the minimum growth rates recorded in summer and July 2010 and almost disappeared in autumn 2009(August to October). The pattern of abundance in phytoplankton was almost reversed, due of many diatoms replaced by blue green algae and the appearance of Euglenophyceae. In Zooplankton copepods dominated over cladocerans and Rotifers which were of less abundance .

The accumulation levels of Cd and Pb in Orechromis niloticus gills confirm the presence of high significant levels of Cd (1.518 ug\g) and Pb (2.l65ug\g) lthle concentration of Cd and Pb in water and fish gills exceeds the permitted limits by WHO and Sudanese standard for drinking water guideline.(Cr,0.005mg/1, Cd=0.005mg/1, Pb=0.05mg/l) . _ The finding contributes to understanding of distribution and dynamics‘ of pollutants in the White Nile ecosystems