Changes in gill structure of the goldfish (Carassius auratus) during sub-chronic exposure to organic pollutants

Organic pollutants are large group of pollutants that cause histological alterations in aquatic animals. These changes are used as indicators to evaluate the effect of human xenobiotic in these organisms and reflect ecosystem general health conditions. This study evaluated the pathologic alterations of gill exposed to Bisphenol A, Naphthalene, Butachlor. These Pollutants were added to aquariums containing goldfish with doses of 500 µg/l, 200 µg/l, 0.28 µl/l respectively, for 15 days, then sampling was performed on days 15. Second gill arc were removed and fixed by Bouins solution, processed, embedded in paraffin, sectioned at 6µ thickness, further stained by Hematoxylin-Eosin staining method. Based on the histological study, secondary lamella curling, lamellar capillaries dilation, complete lamellar fusion, degeneration of epithelium of filaments and second lamella in gill tissue. It seems these alterations in gills were formed to prevent pollutants to penetrate to fish body.