ISSN: 2577-4050
Authors: Awoke JS*, Nwele HO, Oti EE and Okoro CB
A semi-static bioassay method was used to study the toxicity effect of acute exposure of a commercial formulation of glyphosate herbicide (Mulsate) on the behaviour and haematological profile of Clarias gariepinus juvenile. Sample fish were exposed to lethal concentrations of mulsate at 0.00mg/l, 55.00mg/l, 65.00mg/l, and 75.00mg/l for 96 hours. Behavioural characteristics observed in exposed fish include respiratory distress, erratic swimming, loss of equilibrium, lethargies and sudden fish death. These varied greatly with differences in concentration of the toxicant. Mortality increased with an increase in concentration of the toxicant. The differences observed in the mortalities of C. gariepinus at varying concentrations were significant (P<0.05), an indication that mortality could be a factor of concentration and time of exposure. After 96 hr of exposure, the LC50 for mulsate glyphosate herbicide was found to be 44.67mg/l. Furthermore, the toxicant led to significant reduction (P<0.05) in haematological parameters as the toxicant concentration increased. Mean Red Blood Cells (RBC), Haemoglobin content (Hb), Packed Cell Volume (PCV), reduced as the concentration of toxicant increased. Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) were significantly different (P <0.05) between the treated and control fish. Our results indicate that the commercial formulation of glyphosate herbicide (Mulsate) is toxic to C. gariepinus. The herbicide must hence be applied with care in our environment particularly close to water bodies to avoid ecotoxicological consequences.
Keywords: Bioassay; Toxicity; Herbicide; Glyphosate; Biota; Haematology
