ABSTRACT Deltamethrin is a pyrethroid insecticide widely used in pest control in Brazilian agriculture. The intensive and disordered use of this pesticide in the Amazon region can drive it into aquatic ecosystems in several ways, but mainly by runoff and leaching. The present study was conceived to determine the acute toxicity (LC50) of a deltamethrin based pesticide (DBP) and to characterize its effects on two biochemical biomarkers, glutathione-S-transferase (GST) and acetylcholinesterase (AChE), in tissues of the electric fish Microsternarchus cf. bilineatus. Fishes were exposed to concentrations of 1, 2, 3, 4 and 5 μg L-1 of DBP for up to 96 hours. For each treatment, the absolute activity of the enzymes GST (muscle and liver) and AChE (muscle and... |