Recycling study of some heavy metals in the Egyptian aquatic ecosystem

Abstract

The effect of season and locality variation on the distribution of heavy metals in ecosystem components (fish, sediment and water) was studied. In fish, the highest mean concentrations of Pb (1.08), Cr (0.62), Cu (1.92), Mn (0.95) and Fe (13.77) were recorded in winter, Zn (8.36) in spring and Cd (1.06) in summer. The lowest concentrations for all metals were in autumn except for Cu and Cr (summer) and Pb (spring). In sediment samples, the highest concentrations (mg/kg wet weight) for Pb (2.7), Cr (0.4), Zn (4.9) and Cu (14) were in winter and autumn and for Cd (1.2), Mn (24.0) and Fe (47.0) in spring. The lowest concentrations for Pb (1.0) and Zn (3.4) were detected in spring, for Cu (0.4) in summer, and for Mn (2.0), Cr (0.0) and Fe (4.0) in autumn. In water the concentrations for Cd and Cu were highest in spring (0.3 and 0.5 mg/kg, respectively) and lowest concentrations were detected in autumn. The maximum concentrations for Zn (0.55) and Fe (0.8) were in autumn and winter and the lowest concentrations in summer. The maximum concentrations for Pb were 0.5 mg/kg in summer and 0.95 mg/kg in autumn. In the Red Sea, fish had the highest concentrations (mg/kg wet weight) of Pb (1.5), Cu (1.8), and Fe (13.8) and the lowest of Zn (1.8). The maximum concentrations of Cr (0.6), Zn (7.0) and Mn (0.5) and the minimum concentrations of Pb (0.4), Cd (0.06) and Fe (6.4) were in Alexandria. Manzala showed the highest concentration of Cd (1.6) and the lowest concentrations of Cr (36.0), Cu (0.80), and Mn (0.02). In sediment, the River Nile showed the maximum concentrations of Cr (0.4), Zn (7.6), Cu (1.0) and Mn (38.6). However, the Red Sea showed the maximum concentrations of Pb (1.9) and Cd (3.2) and the minimum concentrations of Cr (0.15), Zn (1.2), Mn (0.8), and Fe (11.1). The highest concentration of Fe (60) and the lowest concentration of Cu (0.30) were in Manzala. Alexandria showed the minimum concentrations of Pb (0.2) and Cd (0.01). In water, the highest concentrations of Cu (0.5), Mn (1.1), and Fe (0.07) and the lowest concentrations of Cr (0.4) were in the River Nile. The Red Sea showed maximum concentrations of Pb (0.5), Cd (0.3), and Cr (0.7), and the minimum concentration of Zn (0.2). The highest concentration of Zn (0.5) and the lowest concentrations of Pb (0.3), Cd (0.05) and Fe (0.5) were in Alexandria.