Identification and Quantification of Organochlorine Pesticides Residues in Water, Sediment and Fish Species from Central Mayokam and Suntai Rivers of Central Taraba State, Nigeria

Abstract

Pesticides use has increased worldwide, particularly due to the low yield of food production as a result of harm caused by pests and unwanted weeds. As a result, residues of these chemical contaminate the environment. Water, sediment and fish (Tilapia zilli, Clarias gariepinus, Mormyrus rume) samples were collected from Mayokam and Suntai river for the determination of levels of organochlorine pesticide residues. The extraction process was performed using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method and GC-MS for separation and detection of pesticides residues. The morphometric and condition factor of the studied fish species were measured. All the fish species sampled in this present study had condition factors > 1. A total of fourteen (14) organochlorine pesticide residues were detected. From the results obtained, the pesticides residues were recorded low in water as compared to that of fish and sediments. Based on the result of the water sample, Beta-lindane recorded higher concentration of 0.39 ppm from Mayokam, follow by Endosulfan II, 0.33 ppm from Suntai and Aldrin, 0.16 ppm from Mayokam River. In the fish samples, Endosulfan II recorded high concentration of 6.02 ppm in Mormyrus rume, 2.56 ppm in Clarias gariepinus and 2.03 in Tilapia zilli from Suntai river follow by Aldrin which recorded the concentration of 2.57 ppm in Mormyrus rume and 1.43 ppm in Tilapia zilli also from Suntai river. Endrin recorded 2.56 ppm in Clarias gariepinus from Mayokam river. Furthermore, about 65% of these residues in fish and sediment were above the MRL values set by World Health Organisation and  Food and Agricultural Organisation (WHO/FAO). The results indicate that there is a high level of contamination of these pesticides in fish 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.