The Determination of Total Mercury and Methyl Mercury Contents of Oily White and Light Style of Persian Gulf Tuna Cans

The levels of total mercury and methyl mercury were measured in 40 tuna cans prepared from Persian Gulf tuna, in Tehran, Iran during 2010. The total mercury and methyl mercury concentrations were determined with a GBC 906 AA flame atomic absorption spectrometer (FAAS) and a Thermo gas chromatograph-mass spectrometer (GC-MS), respectively. The results showed that the means of total mercury and methyl mercury content of white and light style tuna were 280.48, 142.75, 229.05 and 113.37ppb, respectively. The white tuna were significantly higher than the light-style one (p<0.05) and probably reflecting that ‘‘white’’ tuna is prepared from species relatively larger than those which are commonly available as ‘‘light’’. The maximum mercury and methyl mercury concentrations were 352.5±2.5 and 303.75±11.43ppb, respectively in white tuna can. The lowest mercury and methyl mercury concentrations were 111±1 and 88ppb, respectively in light tuna can. According to the results, methyl mercury composed about 65-96% (mean 80%) of total mercury in tuna cans. At the present study, the total mercury content of Persian Gulf canned tuna significantly were increased and may be related to utilization of different population of tuna in industrial units and mercury application in recent years.