Assessment of water and sediment quality of the river nile, damietta branch, Egypt

Abstract

Water of Damietta Branch, River Nile is contaminated by different domestic and industrial wastes. It contains various inorganic, organic and biological pollutants which causes serious environmental impacts and significance. This study performed to assess the pollution degree in Damietta Branch-River Nile. Twelve different sampling points were selected along the study area, River Nile Damietta branch from its spring at Cairo to its estuaries at Ras ELbar-Damietta. The results revealed that Dissolved Oxygen concentrations in river water ranged from 2.7 to 9.2 mg/l; BOD values were in the range of 10.5 to 40.6 mg/l, whereas Chemical Oxygen Demand ranged from 30.6 to 92 mg/l. Total nitrogen ranged from 0.125 to 1.4 mg/l. Total phosphorus ranged from 1.1 to 2.8 mg/l. Also, a high concentration of dissolved and suspended salts as total salts ranged from 38.49 to 93.04 mg/l. These results also confirmed with sediment analysis. The concentrations of heavy metals in sediment samples, followed the order Fe> Zn> Pb> Co> Ni> Cu> Mg, while, in the water samples it followed the order Pb> Fe> Cu> Co> Cd> Ni. Through the results of water quality index (WQI) based on 10 critical parameters (pH, Temperature, DO, BOD, COD, TP, TN, Turbidity, TS and Salinity), it indicated that site 5 (Eladlia WQI= 49), site 8 (Bosat Kareem Eldein WQI=47), site 9 (Talkha WQI=45) and site 10 (Smnood WQI=45) were more polluted than the other sites along the river branch. Overall, the results of WQI indicated that the Nile water quality of the studied area classified as medium quality (WQI average 55). The concentrations of Fe, Zn and Cu in water samples were within the safe limits of Egyptian standard regularities of article 60 law No. 48/1982. By contrast, the concentrations of Cd and Pb in water samples were above safe limits.