Assessment of Organochlorines Pesticides Residues in Water, Fish and Sediment Samples from Wurbo Lake, Bali, Taraba State, Nigeria

Abstract

Organochlorines pesticides (OCPs) have been used worldwide, particularly in many African countries as in Nigeria for the control of pests. OCPs are characterized by their bioaccumulation in the environment, especially in the food chain, where they find their way into the human body. The research was aim to estimate the residual concentrations of different OCPs in water, fish and sediment from Kundi Lake to find out the extent of pesticide contamination and accumulation. The water sample was subjected to liquid-liquid extraction method while the fish and the sediment samples were subjected to soxhlet extraction. The extracts were later analysed for organochlorines pesticide residues using Gas-Chromatography coupled with mass spectrometer (GC-MS). The average length, average weight and condition factor of the studied fish species were measured. The Mormyrus rume had the highest average length of 17.12±0.05 cm, and average weight of 195.36±0.05 g follow by Clarias gariepinus which had the average length of 16.83±0.01 cm, and average weight of 189.43±0.03 g. Tilapia zilli was the least species of fish sample with a length of 12.75±0.03 cm and average weight of 102.21±0.02 g. Also, all the fish species sampled in this present study had condition factors>1. Based on the results obtained from all samples, it was found that the levels of organochlorine pesticides residues in water were generally below MRL as compared with FAO/WHO (0.5ppm). In fish samples, highest concentration of pesticide residues in Mormyrus rume follow by Clarias gariepinus, while the Tilapia zilli recorded low concentration of the pesticide residues. The Endosulfan II recorded high concentration of 4.68 ppm in Mormyrus rume follow by Endrin which recorded the concentration of 2.75 ppm, Aldrin 1.78 ppm and Atrazine 1.72 ppm all in Mormyrus rume. In Clarias gariepinus, Simazine 1.56 ppm follows by Endosulfan I 1.28 ppm while In Tilapia zilli, Endosulfan II 1.16 ppm follows by Atrazine 0.91 ppm and Beta Lindane 0.81 ppm. The results indicate that the area is contaminated with high levels of these pesticides in fish and sediment which may pose a great danger to the environment. Regular monitoring is therefore required to control the levels of pesticide residues in the water bodies.