Effect of Lead and Chromium on the Toxicity of Glyphosate Herbicides to African Catfish Clarias Gariepinus (Burchell 1822)

There is a growing increase in pollution of the aquatic ecosystems with a wide range of chemicals including herbicides and heavy metals input through anthropogenic activities, leading to disruption of ecological balance. This study used a static toxicity bioassay to examine the interaction between heavy metals (Pb and Cr) and organophosphorus herbicides (analytical grade glyphosate, commercially formulated - Roundup and Forceup) on African catfish (Clarias gariepinus BURCHELL 1822). Lethal concentrations (LC50) for roundup (RU), forceup (FU), analytical grade glyphosate (AGG), chromium (Cr), and lead (Pb) were 17.23 mg/l, 4877 mg/l, 131.12 mg/l, 21.16 mg/l, and 74.82 mg/l respectively. In addition, fish exposed to varying concentration of chromium (5.0 mg/l and 7.5 mg/l) and lead (20 mg/l and 25 mg/l) with glyphosate (RU: 10 mg/l; FU: 4300 mg/l; and AGG: 100 mg/l) for 96 hours were examined for biochemical parameters. Blood plasma examined for liver and kidney profile indices showed that kidney functions’ parameters (protein, albumin, AST-aspartate aminotransferase, ALT-alanine aminotransferase and Bilirubin) and liver functions parameters (urea and creatinine) increased significantly (p<0.05) when glyphosates combined with lead and chromium treated groups compared with the control group. This study therefore, showed that low concentrations of combined toxicants of glyphosates and heavy metals (Cr and Pb) will synergistically induce deleterious effects on the liver and kidney of Clarias gariepinus.