Mercury, cadmium and lead content of canned tuna fish

Mercury levels in canned tuna fish were determined by cold vapour atomic absorption spectrophotometry while cadmium and lead levels were determined by flame atomic absorption spectrophotometry. The metal contents in the samples, expressed in μg g−1 wet weight, varied from 0.20 to 0.66 with an average value of 0.29 for mercury, from 0.09 to 0.32 with an average value of 0.18 for cadmium and from 0.18 to 0.40 with an average value of 0.28 for lead. The results of this study indicate that tuna fish from the Mediterranean coast of Libya have concentrations well below the permissible levels for these toxic metals. Their contribution to the body burden can therefore be considered negligible.