Abstract
This present research examines the effects of water pollution on fish inhabiting the sites by monitoring physicochemical parameters and biomarkers at five stations with diverse levels of pollution. The selected sites targeted, basic upstream site, agricultural impact site, wastewater infested site, pollution mix site and the last one industrial downstream site. Solutions of water intensity were taken in order to determine the pH, DO and heavy metal ions (Pb, Hg, Cd). Fish species, which consider cyprinids is the common carp (Cyprinus carpio) were collected for biochemical, histopathological, and molecular biomarker assessments. Based on the result obtained in the descriptive statistical analysis, the level of heavy metals in water samples collected from Euphrates River was observed to have a relatively high level of variation with the most polluted sites recording the highest concentrations of heavy metals, specifically sites 4 and 5. F test calculated from the ANOVA was found positive when tested for the parameters by comparing pH, DO and heavy metals where there is a significant difference (p < 0.05) between the various sites. Decreased acetylcholinesterase (AChE) activity and increased catalase (CAT) activity pertaining to neurotoxicity and oxidative stress was observed in the fish belonging to polluted sites by biochemical analysis done on them. Histopathological observation disclosed that the liver tissue exhibited necrosis at its highest degree and gill epithelium had hyperplastic changes at the highest level of exposure. Tissue samples have shown that sites 4/5, fish are experiencing up-regulation stress genes. The findings underscore the profound impact of industrial and urban pollution on aquatic ecosystems, emphasizing the need for stringent pollution control measures. This study contributes to the broader scientific understanding of the ecological consequences of water pollution and underscores the utility of biomarkers in environmental monitoring and management.