Bioconcentration and Acute Intoxication of Brazilian Freshwater Fishes by the Methyl Parathion Organophosphate Pesticide

Figure 1

Tissue distribution of cholinesterase activity in pacu, piavussu and curimbatá (control fish). The box shows the substrates used in enzyme assays. Results are expressed as μmol of products formed per minute per gram of wet tissue (U g⁻¹) or per mL of serum (U mL⁻¹). Liver and brain ChE activities were assayed in homogenates, while heart and muscle ChE activities were assayed in the enzymatic fraction solubilized with Triton and NaCl. Results are average values with the corresponding SEM of assays carried out in five individuals of each species.