Histological Alterations in Kidney of Two Fresh Water Fish Species Living Karasu River, Erzurum, Turkey

Abstract

Karasu River, the only river in the Erzurum plain, is the source of the famous river Euphrates. It is considered that artificial fertilizers, insecticides, municipal sewage, industrial effluents and factory wastes are polluted the river. The pollution in the Karasu River also threatens the Euphrates basin. Fish live in direct contact with their immediate external environment. Therefore, fish are frequently used to determination of aquatic pollution. In this study, Capoeta capoeta and Leuciscus cephalus were caught at three different sites in Karasu River, namely Aşkale, Dumlu and Serçeme. The histological changes kidney of fish were detected microscopically and evaluated with quantitative analyses. Also, heavy metals have been determined in the surface water samples in these sites. Results showed that the Aşkale site was polluted by different kinds of heavy metals. In Aşkale site, some heavy metals such as Cd, Al, As, Pb and Mn levels were mostly detected at concentrations above the TSE values. Meanwhile, various histopathological abnormalities were observed in kidney of the fish species. The observed histological alterations in kidney included glomerulopathy with dilated Bowman’s space, degenerations of renal parenchyma and tubuli, melanomacrophages aggregates, vacuolar hypertrophy of tubule epithelium, glomerular pleomorphism and  congestion. It was found that the pathological frequency was not significant between the fish species. All of abnormalities were observed in both fish species. The pathologic abnormalities did not show significant increasing between fish species caught from Serçeme and Dumlu streams, statistically. But, the pathology increased in Aşkale site and this increase was found to be statistically significant. The increase in histopathology and heavy metal levels indicate that the Karasu River is contaminated with toxic pollutants and the observed abnormalities are related to the discharge of wastes into the river.