Metabolism and Oxidative Stress Biomarkers in Clam Ruditapes decussatus to Assess Pollution in Industrial Area of Mediterranean Lagoon

Abstract

Coastal lagoons are complex and dynamic ecosystems, characterized by a constant fluctuation of environmental conditions. Due to urban development, industrialisation and tourism, lagoons are mainly considered as extensively modified and threatened ecosystem. The purpose of this study is to assess the efficiency of a multibiomarker approach in clam Ruditapes decussatus sampled seasonally from industrial area of Tunis lagoon. Control samples were collected at the reference site "Louza". Benzo[a]pyrene hydroxylase (BPH) and Glutathione-S-transferase (GST) activities were used as a phase I and phase II detoxification enzyme. Catalase (CAT) activity and lipid peroxidation were analyzed as oxidative stress markers. Lipid peroxidation was assessed using malondialdehyde (MDA) accumulation. Results showed a significant increase of all biomarker levels compared with controls. Moreover, the responses of four biomarkers fluctuated over time. BPH and GST activities showed a progressive increase from winter to autumn. CAT activity reached a maximum value in spring; while MDA concentration recorded a maximum value in summer. Seasonal variation of biomarkers arises from a complex interaction between exogenous and endogenous factors. These results confirm the efficiency of the multibiomarker approach used in this study for the detection of biologic responses in Ruditapes decussatus to environmental pollution and to confirm the presence of anthropogenic contaminants in the area of study, which essentially due to the industrial rejections.