Keywords: cadmium, fish gills, scanning electron microscopy, freshwater teleosteans, Cyprinus carpio, Australoheros facetum, Astyanax fasciatus, freshwater ecotoxicology, water pollution, surface gill morphology, gill damage
Effects of sublethal waterborne cadmium on gills in three teleosteans species: scanning electron microscope study
The effects of acute exposure for 96 h to a sublethal concentration of cadmium (300 µg L−1) on the surface gill morphology of the teleosteans Cyprinus carpio, Australoheros facetum and Astyanax fasciatus were studied using Scanning Electron Microscopy (SEM). The main cadmium-induced gill damages in the three species were: structural alterations, oedema and fusion of adjacent secondary lamellae; there was a remarkable disruption of the gill epithelium in Australoheros facetum and excretion of large amount of mucus on the lamellae in Astyanax fasciatus. The reversibility of the alterations after a depuration period was also investigated; in all cases the fishes exhibited a considerable recovery of the gill structure after 96 h in a cadmium-free medium.