Effect of waterborne potassium permanganate exposure on manganese content in liver and axial muscle of channel catfish

Adult channel catfish Ictalurus punctatus were exposed to waterborne potass ium permanganate for 12 weeks to determine if such exposure would alter the manganese content of axial muscle or liver tissue. Continuous exposure to 0.5 mg KMnO4/L or exposlire to 1 or 2 mg KMnO4/L on alternate days did not cause a significant increase in manganese in axial muscle or liver tissue. The mean (+/-SE) concentration of manganese in axial muscle of unexposed co ntrols was 0.262 +/- 0.018 mg/kg (wet weight). Means of manganese concentra tions in axial muscle of the three exposure groups during the 12 weeks of e xposure were 0.289 +/- 0.021 mg/kg, 0.269 +/- 0.018 mg/kg, and 0.239 +/- 0. 013 mg/kg for 0.5 (continuous), 1, or 2 mg/L (alternate days), respectively . At specific sampling times there were differences between controls and ex posure groups; however, no trend toward higher or lower manganese concentra tions in muscle could be detected within groups. The mean (+/-SE) concentra tion of manganese in liver tissue of controls was 1.67 +/- 0.09 mg/kg (wet weight). Manganese concentrations in liver tissue of the three exposure gro ups were 1.57 +/- 0.07 mg/kg, 1.68 +/- 0.08 mg/kg, and 1.58 +/- 0.10 mg/kg, for 0.5 (continuous), 1, or 2 mg/L (alternate days), respectively. Mangane se was thought to accumulate in liver tissue, however, there were no statis tically significant differences between those groups and the controls. Resu lts suggest that potassium permanganate used as a waterborne disease therap eutant for channel catfish does not alter manganese content of edible muscl e of channel catfish and should not present any hazard to human consumers.