Heavy metals content of canned tuna fish
In this study, five heavy metals in canned tuna fish were determined after digestion by the Association of Official Analytical Chemists methods. Mercury and arsenic levels in canned tuna fish were determined by hydride generation atomic absorption spectrophotometery while cadmium and lead levels were determined by graphite tube atomic absorption spectrophotometery and tin levels were determined by flame atomic absorption spectrophotometery. The metal contents, expressed in μg g−1 wet weight, varied from 0.043 to 0.253 with an average value of 0.117 for mercury, from 0.0369 to 0.2618 with an average value of 0.128 for arsenic, from 0.0046 to 0.0720 with an average value of 0.0223 for cadmium, from 0.0126 to. 0726 with an average value of 0.0366 for lead and non detectable for tin.
Several samples were spiked with known amounts of metals. Recoveries of the metals were in the range of 91.7 ± 2.89–99.3 ± 4.03%. The results of this study indicate that tuna fish from the Persian gulf area of Iran have concentrations well below the permissible FAO/WHO levels for these toxic metals. Their contribution to the body burden can be therefore considered negligible and the fish seem to be safe for human consumption.