The species of free fatty acids (FFAs) in the sediments of some important rivers of South-Western Nigeria were analyzed to provide baseline data / information for their levels in Nigeria river sediments. The standard methods based on lipid extraction, isolation and methylation of the free fatty acids were modified and Gas chromatograph based on flame ionization detector was used for quantitative analysis of the complex mixtures of the free fatty acids. The results reveals that palmitic acid (C16:0) is the predominant FFA species, followed by unsaturated C-18 fatty acid (C18:u). Stearic acid (C18:0), lauric acid (C12:0), myristic acid (C14:0) are present in medium concentration while myristoleic acid (C14:1) is present in trace quantities. The average concentrations of the FFA species in all the river sediment samples of the dry and wet seasons are 101.37±19.60 µg/kg and 98.99.46±29.65 µg/kg respectively. These represent the baseline data on which further studies on FFAs in rivers sediments of Nigeria could be based.
