420DISTRIBUTION, SOURCES AND CONTAMINATION RISK ASSESSMENT OF SOME TRACE METALS IN BOTTOM SEDIMENTS FROM SELECTED LOCATIONS IN LAGOS LAGOON, SOUTH WESTERN NIGERIALagos lagoon can be described as a depository of last resort for all the solid and liquid wastes generated in the adjoining land area. In order to assess the current trends in trace metal concentrations from crustal, industrial and domestic source ;Fe, Mo, Zn, Cu, Pb, Ni and Cr in bottom sediments from twelve stations in Lagos Lagoon, were analysed by Atomic Absorption Spectrophotometer (AAS) after acid digestion. The mean concentration of the sediments are as follows:11,425.74mg/kg(Fe), 367.75mg/kg(Mn), 259.78mg/kg(Zn), 14.94mg/kg(Cu), 13.27mg/kg(Pb), 9.38mg/kg(Ni) and 6.00mg/kg(Cr). Potential contamination benchmarks; contamination factor (CF), enrichment factor (EF), geoaccumulation factor (Lgeo) and pollution load index (PLI), were used to assess whether, the observed concentrations represent background and contaminated levels. Based on these; it was concluded that zinc metal represents a contaminated level in the analysed sediments, but the overall toxicity level of the Lagos Lagoon sediments to the aquatic biota is lowlekanpoesam@gmail.comResearch5122015Lagos lagoon, Solid and liquid wastes,Atomic Absorption Spectrophotometer,Background and contaminated levels,Sediments,Toxicity levelPopoola Samuel Olatunde,Oyatola Opeyemi Otolorin,AppiaJoupeleJuliano,Ebohon Joy OsiuareDepartment of Physical and Chemical Oceanography, Nigerian Institute for Oceanography and Marine Research, P.M.B, 12729, Lagos, Nigeria,,Department of Physical and Chemical Oceanography, Nigerian Institute for Oceanography and Marine Research, P.M.B, 12729, Lagos, Nigeria,,Department of marine geology and geophysics, Nigerian institute for oceanography and Marine Research, PMB, 12729, Lagos, Nigeria,Department of Biological Oceanography, Nigerian Institute for Oceanography and Marine Research, P.M.B, 12729, Lagos, Nigeria