Histological analysis of fish gills as an indicator of water pollution in the Tamiš River

Abstract

Water pollution and effects of waterborne pollutants on aquatic organisms and humans have become a great concern over the last few decades. Since fish gills are in direct contact with the environment and are very sensitive to changes in water quality, the aim of this study was to evaluate the effects of waterborne pollutants from the Tamiš River on gill histology. The sample included a total of 78 individuals of the following fish species: wels catfish (Silurus glanis), pike (Esox lucius), roach (Rutilus rutilus), chub (Squalius cephalus), freshwater bream (Abramis brama), Prussian carp (Carassius gibelio) and pike-perch (Sander lucioperca). Histological observations showed moderate to intense histological alterations of the gill tissue. Progressive histological alterations were the most abundant in most of the species analyzed. The most common progressive alterations were hyperplasia and hypertrophy of the gill epithelium. Epithelial lifting was the most common regressive alteration and was observed in virtually all fish species. Circulatory disturbances were slightly pronounced. Results show that the histological alterations in the gill tissue were most likely caused by increased concentrations of certain pollutants. Furthermore, these results are an additional reason to proceed with detailed monitoring of the Tamiš River and the wildlife therein.