Organochlorine Pesticide Residues in Water, Sediment and Various Species of Fish from Komadugu River Basin, Yobe State, Nigeria.

Abstract

Water, sediment and fish (Clariasanguillaris, Tilapia zilli, Synodontisbudgetti and Heterotisniloticus) samples from Komadugu river basin of Yobe State, Nigeria were collected on seasonal basis (rainy, dry seasons and harmattan period) for the determination of the levels of organochlorine pesticide residues (OCPs). Extraction and clean-up of water, sediment and fish samples for OCPs was carried out using standard procedures. The concentrations of all the OCPs in water, sediment fish samples were determined using GC/MS SHIMADZU (Agilent 7890A).The total concentration of OCPs in water samples from the study area ranged from 6.70E-01 μg/L to 2.55E+00 μg/L. The concentrations of OCPs in the different species of fish samples ranged from2.00E-02 to 1.42E+00 mg/kg. Alderin shows the highest concentration (1.42E+00 mg/kg)during the rainy season. The total OCPs (7.26E+00mg/kg)was obtained during the rainy season, while the lowest concentration of 5.68E+00 mg/kg was recorded during the dry season.The concentrations of OCPs residues in sediment samples studied ranged from 1.03E+00 to 1.20E+01 mg/kg, with dieldrin showing the highest total concentration of 1.20E+01 mg/kg during the rainy season. Dieldrin was the most abundant pesticide residues in the studied water, sediment and fish samples. The highest levels of all the studied pesticides were observed during the rainy season when compared to harmattan period and the dry season. This study revealed that pesticide residues levels in the fish samples studied were above the maximum residue limits (MRLs) and acceptable dietary intake (ADI) and could be an important process of transferring pesticides to humans.