U.S. Food and Drug Administration survey of methyl mercury in canned tuna.

Methyl mercury was determined by the U.S. Food and Drug Administration (FDA) in 220 samples of canned tuna collected in 1991. Samples were chosen to represent different styles, colors, and packs as available. Emphasis was placed on water-packed tuna, small can size, and the highest-volume brand names. The average methyl mercury (expressed as Hg) found for the 220 samples was 0.17 ppm; the range was < 0.10-0.75 ppm. Statistically, a significantly higher level of methyl mercury was found in solid white and chunk white tuna than was found in chunk light and chunk tuna. Methyl mercury level was not related to can size. None of the 220 samples had methyl mercury levels that exceeded the 1 ppm FDA action level.