Patterns of Bottom Sediment Contamination in Parts of River Ogun Lagos, Nigeria

The study analyzed the patterns of bottom sediment contamination in parts of

River Ogun Lagos, Nigeria. Samples were randomly collected from ten locations and were

analyzed for ten heavy metals using the digestion and atomic absorption spectrophotometer

technique. Data were analyzed using descriptive and environmental indicators. The result

shows that the concentrations of Pb, Cd, As, Cu and Hg exceeded the global background values

of bottom sediment in the study area. The contamination factors of Pb, As, Cd and Hg indicate

very high contamination. All the locations indicate pollution based on the PLI value. Half of

the locations indicate very severe contamination based on the pollution contamination index

with contributions from Pb, Cd, As, Cu and Hg. The I-geo of Cr, Ni, As and Cu indicate low

contamination while only 40 and 30% of the locations are indicative of heavy and extremely

contamination based on the I-geo of Mn and Cd respectively. The study concluded that Ogudu

is the worst site based on heavy metal concentrations, Cf, and PLI. The study provides useful

baseline information on heavy metal concentrations and ecological risk of bottom sediments

contamination in the study area. Proper monitoring and regulation of heavy metal in the aquatic

environment for policy decisions with greater priority at Ogudu due to its worst quality status

were proffered.