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 potassium 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 controls was 0.262 +/- 0.018 mg/kg (wet weight). Means of manganese concentrations in axial muscle of the three exposure groups during the 12 weeks of exposure 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 exposure groups; however, no trend toward higher or lower manganese concentrations in muscle could be detected within groups. The mean (+/-SE) concentration 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 groups 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. Manganese was thought to accumulate in liver tissue, however, there were no statistically significant differences between those groups and the controls. Results suggest that potassium permanganate used as a waterborne disease therapeutant for channel catfish does not alter manganese content of edible muscle of channel catfish and should not present any hazard to human consumers.