Impact of Bauxite Ore Powder on Histomorphology of Renal Tissue of Spotted Snakehead Fish, Channa punctatus (Bloch, 1793)

Bauxite extraction and the waste it produces are recognized as major contributors to water pollution, especially in areas lacking effective environmental controls. The runoff from bauxite mining contains heavy metals and alkaline compounds. These compounds have been reported to impose deleterious impact not only on physico- chemical properties of nearby soil and water bodies, but also on the organisms inhabiting in them. Present study was aimed to assess the impact of bauxite exposure on the histological structure of the kidney in Channa punctatus. Fish were divided into 3 groups with 5 individuals in each. Group 1 served as control. Fish in group 2 and 3 were treated with low (1/10th of LC50; 0.4212 g/L) and high (1/3rd of LC50; 1.5 g/L) dosage of bauxite powder, respectively. 24 h LC50 (4.212 g/L) of the bauxite was taken from previously published report. Duration of the exposure was kept acute (15 days) and chronic (30 days) for group 2 and 3, respectively. At the end of the experiment, kidney tissues of fish from each group were collected and processed for histological preparation. The tissue sections were stained with hematoxylin and eosin for evaluation of histological changes. Histological alterations in the kidney post- intoxication with bauxite were expressed in terms of presence of clusters of hematopoietic cells, disintegration in renal epithelium, cytoplasmic vacuolization, loss of nucleus, focal lipidosis and distortion of glomerulus and Bowman’s capsule. The extent of damage increased with increasing the dose and duration of exposure. The findings demonstrated that bauxite exposure induced significant renal histomorphological alterations in Channa punctatus, highlighting its potential ecological risk in freshwater environments. This study supports the use of Channa punctatus as a sentinel species for aquatic pollution monitoring and underscores the need for stricter regulation for bauxite mining activities.