Authors: RAJBIR KAUR, ANISH DUA
Abstract: Labeo rohita were subjected to chronic (15, 30, and 60 days) and recovery (60 days) experiments for kidney histopathology studies using sublethal concentrations (35.4%, 26.6%, and 17.7%) of municipal wastewater collected from Tung Dhab Drain, Amritsar, India. Control fish were maintained simultaneously using laboratory tap water, and exhibited normal structures. The results exhibited both dose- and duration-dependent alterations in exposed tissues. The mean degree of tissue change (DTC) values in treated groups ranged from 37.5 ± 6.60 (17.7%, 15 days) to 149.33 ± 7.75 (35.4%, 60 days), demonstrating reparable to irreparable structural changes. The recorded observations showed changes in tubules that included nuclear and cellular hypertrophy, cytoplasmic vacuolation, narrowing of the tubular lumen (stage I), hyaline droplet degeneration, occlusion of the tubular lumen (stage II), and tubular necrosis (stage III). Clear damage was also witnessed in corpuscles that included enlargement of glomerulus, dilatation of glomerular capillaries (stage I), and reduction of Bowman's space (stage II). The recovery experiments showed statistically significant improvement, as the intensity of damage was less than that recorded after 60 days of treatment. The present study indicates toxicity of drain water at the cellular and organ levels, and recommends the use of kidney histopathology as an analytical tool in toxicology and water surveillance studies.
Keywords: Municipal wastewater, water quality parameters, Labeo rohita, kidney lesions, degree of tissue change
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