AN EVALUATION OF POLLUTANT INDUCED CHANGES IN THE GILLS OF RAINBOW-TROUT USING SCANNING ELECTRON-MICROSCOPY

The effects of phenol, copper and ammonia on the surface ultrastructure of the gills of rainbow trout were determined by scanning electron microscopy (SEM). Although the gills exhibited some common pollutant-induced changes, certain types of pathological response were pollutant-specific. Phenol caused destruction of epithelial layers down to supporting cartilage. Copper damage was characterized by lamellar fusion, swelling in the tips of the filaments and formation of epithelial swellings and ridges. Ammonia caused the development of distinctive circular depressions and pits in the epithelium. These results suggest that SEM of fish gills should be evaluated further as a diagnostic tool in water pollution investigations.