Pesticides distribution in surface waters and sediments of lotic and lentic ecosystems in Agbede wetlands

An investigation on the availability and distribution of Lindane (HCHs) and Total organochlorine phosphate (TOCP) in the surface waters and sediments of selected water bodies in Agbede wetlands was carried out from December, 2012 to May, 2014 in order to cover seasonal trends in both matrixes. A Gas Chromatograph model Hewlett-Packard (HP9) 5890 Series II equipped with 63Ni Electron Capture Detector (ECD) of activity 15 mCi with an auto sampler was employed for the analysis of the water and sediment samples in the laboratory under standard condition. Spatial and temporal variations showed that the concentrations of TOCP closely followed that of Lindane in surface water and was a replica in the sediment matrix. Meanwhile, the values obtained for Lindane and TOCP in the sediment were slightly higher than (about 3 folds) that in the surface waters. The concentrations of pesticides in the surface waters and sediments of lotic and lentic ecosystems in Agbede wetlands were found to be far below the set limit of 0.01μgL-1 by the Federal Ministry of Environment of Nigeria (FMEnv) and World Health Organisation (WHO) respectively. The low values recorded in this study suggested seldom application of pesticides particularly on a subsistence form and therefore not indicative of possibility of any serious health issues.Key Words: Below Detection Limit, Concentrations, Ecological Zone, Lindan