Histological Response of Clarias gariepinus to Varying Concentrations of Pharmaceutical Effluents

Abstract

For the past few decades, environmental pollution is considered a major global problem for public health and this problem has continued to impact aquatic environment. Pharmaceutical discharges are major sources of pollution that poses serious threat to aquatic animals like fish, therefore, this work aimed at evaluating the histological architecture of the gill tissues of Clarias gariepinus on exposed to sub-lethal concentrations of pharmaceutical effluents using standard laboratory procedure. The physicochemical characteristics of the pharmaceutical effluent used revealed varied level of deviations from World Health Organization standard for waste discharge into any categories of water bodies. The histological studies of the sectioned gills of the exposed fish showed varied level of histological alterations which are concentrations dependent. The observed histopathological lesions recorded include infiltration of secondary lamellae, inter-lamellae hyper plastic lesion, and oedema, congestion of the blood vessels, epithelial thickening and lifting, and necrosis of various degrees. All the fish held in the control stock showed inappreciable or no histological degradation and their staining patterns and cellular arrangement remained unaffected and this showed that even low concentration of such effluent is enough to induce physiological imbalances in aquatic organisms. The degrees of all these recorded anomalies were concentration dependent. Therefore, indiscriminate disposal of this effluent is detrimental to aquatic community and to combat this, strict compliance of the laws with total vigilance against illegal discharge of effluent should be enacted and enforced.