MODIFY QUECHER’S EXTRACTION METHOD FOR THE DETERMINATION OF ORGANOPHOSPHATE PESTICIDE RESIDUES IN FISH SAMPLES COLLECTED FROM WURBO AND YELWA LAKES OF BALI, TARABA STATE, NIGERIA

Abstract

Organophosphate pesticides (OPPs) have been used worldwide, particularly in many African countries especially in Nigeria for the control of pests and weeds for agricultural purposes. Despite the positive outcomes of using pesticides in agriculture, their usage often results in various harmful environmental and health effects on water systems and aquatic organisms. Pesticides, due to their toxicity and impact on biological components, can be termed as biocides—that is, compounds capable of harming all forms of living organisms, including their intended targets. This research was aimed at determining the residual levels of organophosphates pesticides residues in fish species from Wurbo and Yelwa lakes to find out the extent of contamination in the area. The extraction process was performed using QuEChERS method.  The extracts were later analyzed for organophosphates pesticide residues using GC-MS. The result showed that the levels of organophosphates pesticides residues in fish samples were higher in Mormyrus rume follow by Clarias gariepinus while the Tilapia zilli recorded low concentration. The total of five organophosphate were recorded. Chlorpyrifos recorded high concentration of 1026.46 ppm in Mormyrus rume from Wurbo lake and 691.92 ppm from Yelwa lake. In Clarias gariepinus, Chlorpyrifos recorded the concentration of 584.45 ppm in Wurbo and 359.41 ppm from Yelwa lake. Ronel recorded levels of 42.53 in Clarias gariepinus and 5.56 ppm in Mormyrus rume from Wurbo. Phosphorodithioic acid recorded the concentration of 8.08 ppm in Clarias gariepinus and 4.84 ppm in Mormyrus rume from Wurbo lake. These values were above the maximum residue limits (MRL) by FAO/WHO, (2009, 2010 & 2021), ranges from 0.001 to 0.5ppm. 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.