Abstract

Levels of lead, iron, zinc, copper, arsenic, cobalt, chromium, manganese, mercury and cadmium, as well as the microbial profile were determined in water samples from Aba River. Physico-chemical examinations revealed that manganese (0.03 mg/l), zinc (4.81 mg/l) and copper (0.19 mg/l) were below the maximum allowable levels set by the United States Environment Protection Agency (USEPA), while lead (0.064 mg/l), iron (0.81 mg/l), arsenic (0.1 mg/l) chromium (0.006 mg/l) and mercury (0.009 mg/l) were high but not significantly. The implication is that waste assimilation capacity of the river is high, a phenomenon attributable to dilution, sedimentation and depuration. Quantitative examinations of the microorganisms present revealed that as many as 2.05 x 108 viable bacterial (cfu/ml) were present. The predominant bacterial forms include Staphylococcus species, Streptococcus faecalis, Escherichia coli, Salmonella species, Bacillus and Clostridium species implying that the abattoir wastes discharged into the river may have had a significant impact on the river ecosystem.

Key words: Waste assimilation, effluent, low level metals, pollution.