Effects of pollution on oxidative stress in aquatic species: case of the fish Sarotherodon melanotheron in Bè Lagoon (Lomé)

Abstract

This study aimed to assess heavy metals accumulation and oxidative stress biomarkers in the fish Sarotherodon melanotheron from a site receiving discharges from industrial and harbor activities (Bè Lagoon) and a reference or control site in Lake Togo, Togo. Atomic absorption spectrophotometry (AAS) targeting four heavy metals (lead, cadmium, copper and nickel) in the waters of Bè Lagoon showed levels of about 2.58 ± 0.11 μg/l, 1.03 ± 0.15 μg/l, 1.71 ± 0.17 μg/l and 3.03 ± 0.07 μg/l respectively for Pb, Cd, Ni, Cu. In water of the control site, only Cu and Ni were detected at lower levels: 1.54 ± 0.22 μg/l for Ni and 0.89 ± 0.18 μg/l for Cu. Furthermore, in tissues (liver, muscle and gills) of the fish, the heavy metal contents are found in larger samples of the Bè Lagoon. Among the biological parameters (oxidative stress biomarkers), the catalase activity (P < 0.0001 in liver and P < 0.005 in gill) was found to be significantly higher in the fish collected from Bè lagoon when compared with control site. These changes in biomarkers response at the subcellular level therefore indicate an impact on the biology of the fishes living in Bè lagoon.

Keywords: Bè lagoon, catalase activity, Lake Togo, MDA, pollution.