HISTOPATHOLOGICAL CHANGES IN GILLS OF FISHES OF DIFFERENT SITES OF NARMADA RIVER AT JABALPUR DUE TO HEAVY METALS AND OTHER CONTAMINANTS.

The present study was undertaken to assess the contamination of heavy metals in different six sites of Narmada River in Jabalpur region. The study was conducted during September, 2022 to February, 2023. Water samples were collected from different sites: Site A (Near Mangeli village, opposite site of Gwarighat), Site B (Khirnighat), Site C (Khandarinala), Site D (Gwarighat), Site E (Tilwaraghat) and Site F (Bhedhaghat) for the analysis of water chemical parameters viz., dissolved oxygen (DO), carbon dioxide (CO₂ ) and total ammonia. Level of DO was found lower in the Site B and Site C as compared to the Site D to F and Site A. Levels of CO₂ and total ammonia were observed higher in the Site B and Site C as compared to the Sites D to F and Site A, indicating more heavy metal contamination in sites B and C as compared to the site D, E and F. Water samples of different Sites A to F were also assessed for presence of heavy metals by spot test. The results indicated the presence of heavy metals (lead, copper and mercury) in the sites B and C. Results showed poor water quality of these sites due to the different anthropogenic activities. Twenty-four fishes (Nile tilapia, Oreochromis niloticus) were collected from different sites for histopathological study. Gill tissues were collected from all fishes. The gills tissues of fishes showed normal structure in control group (Site A). In the fishes of Site B, the gill section showed necrosis of epithelial cells of secondary gill lamellae. In the fishes of Site C, the gill section showed degeneration of gill lamellae and hyperplasia of chloride cells. In the fishes of Site D, the gill sections showed degenerative changes and disruption of primary gill lamellae. However, the gill tissues showed degeneration of gill lamellae and secondary gill lamellae in the fishes of Site E. Similarly, the gill tissues showed degeneration and disruption in the fishes of Site F. [ABSTRACT FROM AUTHOR]