Abstract

The behaviour and fate of pesticides in the environment will determine their impact on both humans and non-target organisms. Biochemical biomarkers are increasingly used in ecological risk assessment to identify the incidence of exposure to and effects caused by xenobiotics. This study was undertaken to investigate the potential toxic effect of a locally produced insect powder called “Rambo” (which contain 0.6% permethrin) on non-target organisms exemplified with albino rats. The results obtained showed that glutathione S-transferase (GST) activity in the newly-weaned rats (NWR) and middle-aged rats (MAR) groups were found to increase significantly (p<0.05) in the liver homogenates at the concentrations used (1, 5 and 10%) compared with their parallel controls. In the plasma and brain homogenates, a decrease in GST activity was observed, this decrease was significant (p<0.05) in the brain homogenates, but in the blood plasma the decrease in GST activity was not significant (p>0.05). However, the highest GST activity (398.44 ± 23.44) U/L was recorded in the liver homogenates while the least activity (9.07 ± 3.44) U/L was obtained in the plasma sample. The significance of such a decrease in intracellular GST is that, protection against reactive intermediates may be lost and thus affect vital metabolic processes that may result to death. This shows that GST can be used as a biomarker in ecological risk assessment of pesticide contaminated environment.

Key words: Glutathione S-transferase, biomarkers, pesticides, risk assessment.