SPATIAL AND TEMPORAL VARIATIONS IN HEAVY METALS CONCENTRATION OF JABI DAM, LOWER USUMA DAM AND GWAGWALADA RIVER IN FEDERAL CAPITAL TERRITORY, ABUJA, NIGERIA

Heavy metal concentrations of Jabi dam, Lower Usuma dam and Gwagwalada River in the Federal Capital Territory, Abuja were investigated between June 2005 and January 2007 in order to assess their composition, concentration and dynamics. Water samples were taken and analyzed for Iron (Fe), Copper (Cu), Lead (Pb), Zinc (Zn), Manganese (Mn), and Magnesium (Mg) using Atomic Absorption Spectrometer (AAS) monthly from these water bodies. The results obtained were subjected to statistical Analysis of Variance (ANOVA). The result revealed that Gwagwalada river had the highest copper mean value of 1.08 mg/l followed by Lower Usuma dam and Jabi dam which had 0.99 mg/l and 0.87 mg/l respectively though the mean concentrations were not significantly different (P>0.05). Lead concentration showed Gwagwalada river to be 3.53 mg/l, Lower Usuma dam 3.06 mg/l and Jabi dam had the least concentration of 2.81 mg/l. however, the differences were not significant at P>0.05. Gwagwalada river had the highest iron mean value of 5.56 mg/l which was significantly different (P<0.05) from those of Jabi and Lower Usuma dams which had 3.14 mg/l and 1.79 mg/l respectively. Zinc mean values were 0.03 mg/l, 0.29 mg/l and 0.03 mg/l for Gwagwalada River, Lower Usuma dam and Jabi dam respectively. Gwagwalada river had the highest Magnesium mean value of 20.86 mg/l which was significantly different (P<0.05) from those of Lower Usuma dam (13.18 mg/l) and Jabi dam (12.62 mg/l). Most of the parameters fell within the acceptable and permissible limit for aquaculture. Cu and Pb had their wet season mean higher than their dry season mean while Fe, Zn and Mn had their dry season mean higher than their water season in the three water bodies studied.