DOWN STREAM

This study uses the piscine micronucleus assay to evaluate environmental contamination in Oreochromis niloticus (Nile tilapia) from the downstream of Ovia River in Edo State. The assay assessed genotoxicity induced by heavy metal pollution in the aquatic environment. Ten (10) fish samples were collected, and heavy metal concentrations were analyzed in the fish skin. Nuclear abnormalities (NAs) such as micronuclei (MN), blebbed cells (BL), notched cells (NC), anucleated (AN), and binucleated (BN) cells were examined in erythrocytes. The results revealed a significant increase in NAs in exposed fish compared to controls, with nuclear abnormality frequencies ranging from 6.02% to 17.45%, and a mean of 9.21%. In contrast, control fish exhibited a lower mean frequency of 0.72%, indicating a statistically significant difference (p ≤ 0.001). Heavy metal analysis revealed elevated concentrations of iron (Fe), lead (Pb), and cadmium (Cd) in the fish skin, suggesting bioaccumulation from contaminated river water. The positive correlation between heavy metal concentrations and micronuclei frequency confirms the genotoxic potential of pollutants in the Ovia River. These findings highlight the necessity for continuous environmental monitoring and pollution control measures to mitigate the impact of toxicants on aquatic biodiversity and human health.