Metals and Histopathological Alterations in the Kidneys of Schizothorax niger, Heckel from the Dal Lake of Kashmir Valley

Abstract

Ruqaya Yousuf, Sajad Hussain Mir, M. M. Darzi, Masood Saleem Mir

The study was conducted to evaluate the metal induced abnormalities in the kidneys of Schizothorax niger, Heckel from Dal lake seasonally for a period of two years. The varied seasonal metal concentrations for copper (64.61 ± 3.10 to 78.90 ± 3.42 ppm), zinc (88.77 ± 3.52 to 101.99 ± 4.03 ppm), iron (200.99 ± 5.04 to 292.61 ± 4.25 ppm) and manganese (0.84 ± 0.06 to 06.95 ± 0.93 ppm) were observed during the entire period of study. The highest concentration of metals was observed in the summer seasons and the lowest concentrations in the winter seasons during the study period. Further, histochemical analysis demonstrated high levels of metal ion (Cu, Fe and Zn) in the kidneys of the fish in summer seasons during the study period. Analysis of these levels demonstrated by wet digestion-based Atomic Absorption and combined with histochemical methods, showed probable relationship between these high metallic levels and kidney pathology. The general changes in the kidneys of the host included tubular atrophy with hypercellularity and hyperplasia. The other changes in the kidneys included mild congestion during winter seasons to severe tubular degeneration during summer seasons. The accumulation of different metals in the kidneys of the host can be attributed to the water pollution of Dal Lake by various metals and the subsequent histological abnormalities can be speculated to be due to the higher sensitivity of the host to different contaminants. From the present study it was concluded that the metals in the environment are polluting the water bodies and their subsequent deleterious effects harm the aquatic fauna particularly the native fish Schizothorax niger which would be one of the reasons for its decline from fresh water resources of the Kashmir Valley.