Seasonal variations of metals and other mineral constituents of River Yobe

Abstract

Water samples were collected from River Yobe during the rainy and dry seasons at Nguru, Gashua,Azbak, Dumsai and Wachakal. The samples were analyzed for their mineral constituents including Zn, Pb, Fe, Mn and Mg using the Atomic Absorption Spectrometry (AAS) while Na, Ca, and K were analyzed using Flame Emission Spectrometry (FES). The ranges of metal concentrations obtained are; Zn (7.06 mg/dm³ – 13.44 mg/dm³), Pb (0.05 mg/dm³ – 0.135mg/dm³), Fe (0.052 mg/dm³ – 0.53 mg/dm³), Mn (0.102 mg/dm³ – 0.383 mg/dm³), Ca (28.50 mg/dm³ – 87.52 mg/dm³), Mg (7.34 mg/dm³ – 29.4 mg/dm³) , Na (13.95mg/dm³ – 22.98 mg/dm³) and K (40.08mg/dm³ – 78.2mg/dm³ ). From the levels of metals analyzed, it can be concluded that concentrations of Zn, Pb, Fe and Mn were all above WHO and SON permissible limits in all sampling areas. This indicates an increase in metal pollution load, probably due to fertilizer movement, agricultural ashes and sewage-effluent run-off wastes. Water samples sourced from this river may however be used for agricultural and irrigation purposes but unfit for human consumption.

Keywords: Metal, Pollution, WHO, Yobe, Waste