Accumulation of Heavy Metals in Long-Evans Rat Through Feeding Fishes of Buriganga River and Their Histopathological Evaluation.

The study was conducted to evaluate the impacts of industrial discharges, including from tanneries, in terms of heavy metal loads in fin-fish of the Buriganga river, Dhaka, Bangladesh, and to find out the ultimate effects of feeding those heavy metal-contaminated fishes to Long-Evans rats to examine rats' heavy metal accumulation along with viable architectural alterations on various organs through histopathological screenings. Being the most edible by the populace, Labeo rohita was chosen for this purpose. Labeo rohita was collected from five different spots in the river close to the industrial outlets, covering three seasons: monsoon, winter, and summer throughout the year. Experiments unearthed that the deposition of heavy metals inside fishes always surpassed the standard margin, implying a pernicious aquatic milieu. The empirical data suggests that the mean concentrations of Cu, Pb, Cr, and Cd were higher than the permissible limits of WHO and FAO after feeding heavy metal-contaminated fishes for a period of 120 days. Seasonal variations were also taken into account, and it was noticed that rats fed with fish collected in winter had the highest heavy metal concentrations (P < 0.05). Significant architectural changes were observed during histopathological screening of rats' livers and kidneys characterized by necrosis, inflammation, and congestion. After gauging the obtained data, it might be concluded that consumption of heavy metal-contaminated fish entails accumulation of heavy metals, which causes histopathological changes in rats' livers and kidneys, including necrosis and severe structural deformational changes compared to those of control groups.