Total mercury and methylmercury in tuna fish and sharks from the South Adriatic Sea

Total mercury and methylmercury concentrations were measured in tuna fish and sharks from the South Adriatic Sea. The highest mean levels of total mercury were found in Squalus acanthias (6.5 mg/kg w.w.). In the other species mean mercury levels were notably lower (0.46 mg/kg w.w. for Auxis rochei: 0.38 mg/kg w.w. for Prionacee glauca). Twenty-two percent of the Auxis rochei samples exceeded the legal Italian limit (0.50 mg/kg w.w.) as specified by the European Commission Directive. No sample of Prionacee glauca exceeded the legal limit of 1 mg/kg wet wt., while all Squalus acanthias samples exceeded this value. The analytical data showed that mercury was present mainly in the organometallic form with percentages between 69 and 100%. For all the species examined, the estimated weekly intake was lower than the Provisional Tolerable Weekly Intake (PTWI) recommended by the FAO/WHO Expert Committee on Food Additives.