Antioxidant and biotransformation responses in Liza aurata under environmental mercury exposure -: Relationship with mercury accumulation and implications for public health

This study was carried out in the Laranjo basin (Ria de Aveiro, Portugal), an area impacted by mercury discharges. Liza aurata oxidative stress and biotransformation responses were assessed in the liver and related to total mercury (Hg-t) concentrations. A seasonal fish survey revealed a sporadic increase in total glutathione (GSH(t)) and elevated muscle Hg-t levels, although Hg levels did not exceed the EU regulatory limit. As a complement study, fish were caged for three days both close to the bottom and on the water surface at three locations, and displayed higher Hg-t levels accompanied by increased GSH(t) content and catalase activity as well as EROD activity inhibition. The bottom group displayed higher hepatic Hg-t and GSH(t) contents compared with the surface group. Globally, both wild and caged fish revealed that the liver accumulates higher Hg-t concentrations than muscle and, thus, better reflects environmental contamination levels. The absence of peroxidative damage in the liver can be attributed to effective detoxification and antioxidant defense. (c) 2008 Elsevier Ltd. All rights reserved.