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

Total mercury and methylmercury concentrations were measured in tuna fish a nd sharks from the South Adriatic Sea. The highest mean levels of total mer cury 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 roch ei samples exceeded the legal Italian limit (0.50 mg/kg w.w.) as specified by the European Commission Directive. No sample of Prionacee glauca exceede d the legal limit of 1 mg/kg wet wt., while all Squalus acanthias samples e xceeded this value. The analytical data showed that mercury was present mai nly in the organometallic form with percentages between 69 and 100%. For al l the species examined, the estimated weekly intake was lower than the Prov isional Tolerable Weekly Intake (PTWI) recommended by the FAO/WHO Expert Co mmittee on Food Additives.