Mercury and omega-3 fatty acids in retail fish sandwiches.

Mercury and fatty acids were measured in fish sandwiches from six retail restaurant chains. Average mercury concentrations ranged from 5 to 132 ppb and were well below the Food and Drug Administration action level (1,000 ppb). The average concentrations of eicosapentaenoic acid plus docosahexaenoic acid ranged from 91 to 620 mg per sandwich. Consuming one or two fish sandwiches per week could result in the consumption of 2 to 40% of the reference dose for mercury for a 60-kg individual and would provide 18 to 126% of the adequate intake for eicosapentaenoic acid plus docosahexaenoic acid as recommended for a pregnant or lactating woman.