Deleterious effects of wastewater on the health status of fish: A field caging study

We carried out a caging field experiment to assess the potential effects of an untreated sewage effluent on the health status of Prochilodus lineatus. We analyzed multiple biomarker responses, which included morphological indices, biochemical and hematological parameters as well as oxidative stress markers. In addition, we investigated the energetic demand of that exposure. Our findings showed that fish caged at the effluent showed a differential physiologic profile, suggesting a strong impact on fish health. Particularly, mortality, monocytosis, transaminase increase, antioxidant enzyme activation, lipid oxidative damage in several tissues and hepatic and muscle glycogen depletion were observed. According to multivariate analysis, oxidative stress markers and metabolic parameters were key biomarkers to contribute in separating fish caged at effluent site from those caged at upstream and downstream sites. So, these biomarkers allied to a caging strategy are recommended for future environmental monitoring assessments.