Xanthate effects on cadmium uptake and intracellular distribution in rainbow trout (Oncorhynchus mykiss) gills

Xanthates can form hydrophobic complexes with heavy metals, thus enhancing bioavailability of the latter to fish. Using the perfused-head technique, uptake of cadmium-109 (and, for comparison, carbon-14-labelled phenol) by trout gills was measured in the presence of xanthates. After perfusion, levels of radioactivity in gill filaments were measured and intracellular distribution of cadmium-109 was determined after homogenization and centrifugation of the tissue. There was an increase in cadmium-109 retention in gill tissue at xanthate concentrations greater than 10 uM, i.e. those concentrations at which hydrophobic complexes are formed. Rate of cadmium transfer through gills was also increased at high xanthate concentrations. Rate of phenol transfer across gill epithelium was much higher than rate of cadmium transfer irrespective of the presence of xanthate, suggesting different uptake mechanisms. Xanthates enhanced binding of cadmium to the membrane-risk subcellular fractions and altered the cytosolic distribution of the metal. Xanthate carried cadmium from the water into branchial epithelial cells, where the complex then dissociated. There are 38 references.