Polychlorinated biphenyl accumulation and hepatic EROD activity in golden grey mullet Liza aurata from Tunis Bay, southern Mediterranean

Abstract

Liza aurata was used as a bioindicator species to monitor contamination by organic xenobiotics of estuarine water at the outlet of Khélij channel [canal], Tunisia, from November 2002 to December 2003. Polychlorinated biphenyl (PCB) concentrations, including coplanar congeners, were measured in mullet muscle tissue. Mean PCB concentrations ranged between 77 and 180 ng g−1 wet weight. The PCB profiles were dominated by hexachlorobiphenyl congeners accounting for 25–52% of the total profiles. Total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents of coplanar PCBs, including mono- and non-ortho congeners, was 4 pg g−1 wet weight in December 2003 vs 82 pg g−1 wet weight in April 2003. Biological effects in mullet were evaluated by measuring ethoxyresorufin-o-deethylase (EROD) activity in fish liver. EROD activity was significantly elevated, compared to baseline values in control fish (43 ± 23 pmol min−1 mg−1 protein). The highest enzymatic activity of 1 202 ± 813 pmol min−1 mg−1 protein was recorded in July 2003.