Sublethal toxicity effects of glyphosate and propanil on some haematological parameters in juveniles of freshwater catfish, Clarias gariepinus (Teugels, 1986)

Abstract

The use of agrochemicals in developing countries for the eradication of different pests/weeds has been on the increasing trend. This might be due to increasing human population, intensive agriculture, industrialization and urbanization. However, the objective of this work is to study the sub-lethal toxicity effects of glyphosate and propanil on some haematological changes in the freshwater fish Clarias gariepinus juveniles. The experiment was conducted in the laboratory for a period of 56 days. Juveniles fish of Clarias gariepinus of mixed sexs, males and females were randomly exposed to sub lethal concentrations of the two herbicides, 0.11, 0.14, 0.21 mg/L and control (0.00 mg/L) for glyphosate and 0.23, 0.31, 0.46 mg/L and control (0.00 mg/L) for propanil respectively. However, blood samples were collected for the determination of some haematological changes after 56 days. Assessment of haematological parameters revealed significant decreases in RBCC, HB and PCV. In contrast, a highly significant (p≤0.05) dose and duration dependent elevation was recorded in WBCC and MCH in all experimental groups compared with control exposures. There was also increased in lymphocytes and decreased in neutrophils counts in glyphosate and propanil exposure of C. gariepinus juveniles. The study has shown that the exposure of the fish C. gariepinus juveniles to the herbicides glyphosate and propanil can lead to alterations in the haematological parameters of both stages of the fish which could inflicts unfavourable physiological changes in the target organism, therefore leading to death of fish. Howerver, there is the need to protect fish with a view to sustaining our rich biodiversity in Nigerian. The study therefore, revealed that exposing C. gariepinus juveniles to sublethal concentrations of glyphosate and propanil causes an upset on the haematological parameters and implies poor environmental fitness for fish exposed to herbicides in natural environments.