Effects of Acute Exposure to Cadmium on the Electrolyte Balance in Plasma of the Carp and Girella.

Abstract

The effects of cadmium exposure on the concentrations of blood plasma electrolytes (sodium, potassium, calcium, and magnesium) in the carp Cyprinus carpio and the girella Girella punctata were examined. In the carp, all four electrolytes examined decreased significantly after 24-h exposure to 0.3mg Cd/l. The total calcium concentration in plasma decreased significantly during the camdium ex-posure. The depression of the total calcium concentration in plasma depended on the ambient cadmium concentration. The total magnesium concentration in plasma increased significantly after a transient decrease. In the girella, the plasma concentrations of sodium and total magnesium increased significantly and the concentrations of potassium and total calcium showed a tendency to decrease during the exposure to 10mg Cd/l. However, the decrease of the total calcium and potassium concentrations in plasma did not necessarily depend on the cadmium concentration in the seawater. The results of the study suggest that cadmium of high concentrations could increase the electro-lyte permeability of the apical plasma membrane of the obsorption site, and that the uptake of potassium and calcium from water into the body of fish could be particularly inhibited by lower cadmium concentrations.