Toxic Metals in Oyo Dumpsite Soils as Potential Hazards to Residents Within Dumpsite Catchment Areas, Southwestern Nigeria

Heavy metals constitute indispensable raw materials in industries, agriculture, medicine and technology contributing to socioeconomic life of man. Though heavy metals are elements required by plant and animals, the toxic level of the metals in soil and water can create serious threats to human health and his environment. The focus of this study is to examine the possible dangers that arbitrary dumping of refuse within residential areas could cause to the environment and the people. Fifteen (15) active dumpsites located between Latitude N07o ا47 to N07o 52¹ and Longitude N003o ا47 to E003o 581 were sampled at 10cm depth to the surface. They were air- dried in the laboratory, sieved to 75µm size and pulverized for geochemical analysis using the Atomic Absorption Spectrophotometric (AAS) method. Results show average values of metal concentration in the soils as Fe (49,032.68ppm), Pb (73110.21ppm), Mn (63.57ppm), Cu (21.20ppm), Ni (6.39ppm), Co (0.04ppm), Zn (28.19ppm), Cd (0.05ppm) and Cr (3.61ppm). Heavy metal pollution in the soils were assessed using geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (Cf), and pollution load index (PLI). Results show that the soils are extremely contaminated with Pb but moderately contaminated in Fe while Mn, Cu, Ni, Co, Zn, Cd and Cr all show low level of contamination. The pollution load index of Fe and Pb show high values. The overall results indicated that Fe and Pb are major source of potential hazards in the study area