SEDIMENT QUALITY ASSESSMENT IN COASTAL COMMUNITIES OF ONDO STATE, NIGERIA

Abstract

Sediments serves as sink for heavy metals and other pollutants in river bodies. Aquatic organisms can accumulate heavy metals through a polluted sediment as most of them obtained their food from it. The present study was undertaken to evaluate the risk of heavy metals in sediment of Oluwa river, Okitipupa Igbokoda axis to aquatic organisms. Eighteen sediments samples were collected in triplicates from the river, digested and analyzed for heavy metals using Proton Induced X-ray Emission (PIXE). The sediment was highly enriched with Fe, Al and Pb having enrichment factors (EF) of 75.3, 51.1 and 12.7 respectively with Cu as normalising elements. The order of Geo-accumulation index (Igeo) in all the samples are Al > Fe > Pb > Mn > Sr with Igeo values 2.102, 2.097, 1.543, 1.373 and 1.279 respectively. The order of Contamination factor Cf in Oluwa river are Pb > Fe > Cd > Zn. The overall Pollution Load Index (PLI) and Ecological risk (Er) for the metals are 5.77 and 207.44 respectively which indicates that the sediments are polluted and toxic to organisms. The main source of these heavy metals in sediment is the improper dumping of waste into the water body. Waste disposal facilities should be provided and monitored for people to prevent continuous deterioration of surface water in coastal Communities.