Metal Concentrations in Sediments of the Ogun River, Nigeria

Abstract

Sediment samples were collected from various locations along the Ogun River basin after which they were subjected to physicochemical analysis in order to determine the concentration of metals in the sediments as well as other sediment characteristics like pH, texture, cation exchange capacity etc. The samples were collected using a Van Veen Sediment grab after which they were stored in labeled polythene bags and transported in ice packed coolers to the laboratory. They were air dried, sieved and hand pulverized. Sediment trace metal analysis was determined using the Inductively Coupled Plasma Optical Emission Spectrometry. Data obtained were subjected to Analysis of Variance (ANOVA). From the results obtained, Cd (1.00 ppm) from Lafenwa sediment exceeded the Environment Canada Sediment Quality Guideline (ECSQG) limit of 0.60 ppm. Pb values from Akin Olugbade (46.00 ppm), Lafenwa (323.00 ppm), Copper (46.00 ppm) from Lafenwa, sediment Hg values obtained ranging from 0.945-0.975 ppm were all reported to be higher than the ECSQG limits of 35ppm for Pb, 35.7 ppm for Cu and 0.17 ppm for Hg respectively. There is need to monitor Cd values in sediment, from all the locations particularly Lafenwa so that appropriate measures can be put in place to reduce increase in Cd concentrations in the Ogun River basin especially from anthropogenic sources such as indiscriminate dumping of wastes into the river. Other metals like Pb, Cu and Hg should also be monitored frequently.