ASSESSMENT OF PESTICIDES RESIDUES IN WATER, SEDIMENT AND MACROBENTHIC INVERTEBRATES (ENALLAGMA SP AND CARIDINA AFRICANA(Kingsley, 1883)) FROM IKPOBA RIVER, NIGERIA

ABSTRACT

The concentration and distribution of pesticide residues in water, sediment, and macrobenthic invertebrates (Enallagmasp and Caridinaafricana) samples collected from the downstream portion of Ikpoba River, Southern Nigeria was investigated to assess the level of pollution. Samples were collected for two months (February and March) and 17analyte pesticides were analysed using the Gas Chromatography(GC), equipped with Electron Capture Detector (GC-ECD). Mean concentration of total pesticide concentrations ranged ND(Not Detected) to 0.732µg/ml in water, 0.0094µg/ml to 0.0926µg/ml in sediment, ND (Not Detected) to 0.0082µg/ml in Enallagmasp, and ND (Not Detected) to 0.001µg/ml in Caridinaafricana. Mean concentration of pesticides were higher in sediment compared to water, Enallagmasp, and Caridinaafricana. Gamma-BHC(Lindane), and Beta-BHC was the most dominant pesticides in all the matrixes making up to 37%in sediment, 5% in water, 54% in Enallagmasp, and 100% in Caridinaafricana. Pesticide levels in water were observed to be within the EU freshwater guidelines of 0.1µg/ml. It is therefore imperative that the pesticides levels in Ikpoba be continually monitored to ensure the guidelines levels are not exceeded, for the safety of aquatic organisms in the Ikpoba River.