Effect of Marine Environment Remediation on Oxidative Stress Indicators and Metals in the Digestive Gland of the Mussel Crenomytilus grayanus

Abstract

The marine environment quality in Gornostai Bay of the Peter the Great Bay, East Sea/Sea of Japan (Russia's Primorski Krai) was assessed based on oxidative stress biomarkers and the content of heavy metals in the digestive gland of the mussel Crenomytilus grayanus. Mussels were collected in Gornostai Bay in 2013, three years after the remediation of a domestic solid waste dump site located on the shore of the bay and in a relatively clean area at Reineke Island (Peter the Great Bay). The results were compared with the data from the studies performed on C. grayanus from the two locations in 1999 and 2011. It is concluded that the marine environment quality in Gornostai Bay is progressively (gradually) improving three years after the remediation of the domestic solid waste dump site compared to 1999 and 2011. IntroductionAerobic species have evolved the capacity to use oxygen for the efficient release of energy. However, in vitro studies suggest that 1-3% of the oxygen molecules used are converted to reactive oxygen species (ROS), including both radical and non-radical species . Therefore, the ROS are continually produced as toxic bi-products of normal metabolism from various endogenous processes [1]. Key biological molecules, notably DNA, proteins, lipids, can all be adversely affected by ROS [2,3]. Furthermore, the reaction of ROS with these macromolecules generates additional ROS, setting in train a cascade of damage if left unchecked [4]. An antioxidant system (represented by low molecular weight free radical scavengers and specific antioxidant enzymes) is present in the body of all aerobes in order to retard the ROS generation processes and to protect the cellular components from oxidation and to repair the oxidized biomolecules [5].The accumulation of heavy metals, petroleum hydrocarbons and polychlorinated phenols in the tissues promotes the formation of ROS [1,6,7]. Molecular biomarkers of oxidative stress (oxidative degradation products of biological molecules and the levels of antioxidants) have been widely used in recent decades to identify the toxic effect of pollutants [8,9].The aim of this study was to use biochemical indicators to assess changes in the marine environment quality after remediation of the anthropogenically polluted coastal zone. For this purpose, the content of heavy metals (Fe, Zn, Cu, Cd and Pb) and indicators of oxidative stress (activity of antioxidant enzymes and levels of reduced glutathione and lipid peroxidation products -diene conjugates, TBAreactive products) as well as total lipid content were determined in the digestive gland of Crenomytilus grayanus (Dunker 1853). Furthermore, studies focused both on the dynamics of release of heavy metals from digestive gland tissue of mussel and the dynamics of changes in biochemical indicators after remediation of the anthropogenically polluted coastal zone are of significant interest.Therefore, a change in the marine environment quality in the Gornostai Bay in 2013 was evaluated based on the changes in contents of metals and b...