Fish is an important food with growing evidence of
potential benefit. However, consumers may have difficulty
in distinguishing among several health messages
about fish consumption. Although strong data associate
cardiovascular disease prevention with increased fish
consumption, there are also concerns about potential
polycarbonate phenols (PCBs) and mercury contamination.
21,22 The Food and Drug Administration (FDA) and
AHA stress that seafood is an important part of a healthy
diet and advocate consumption of a wide variety of
fish and shellfish. Current FDA recommendations with
regard to limiting fish intake pertain to women who
may become pregnant or are already pregnant, nursing
mothers, and young children. The FDA recommends
that people in those categories avoid shark, swordfish,
king mackerel, and tilefish because they contain high
levels of mercury. Five of the most commonly eaten
varieties of fish are low in mercury (shrimp, canned light
tuna, salmon, pollack, and catfish). The AHA continues
to recommend 2 servings of fish weekly.23
http://aappolicy.aappublications.org...;117/2/544.pdf
The methylmercury content of fish varies by species
and size of fish and harvest location. The top 10
commercial fish species (canned tuna, shrimp, pollock,
salmon, cod, catfish, clams, flatfish, crabs, and
scallops), which represent about 85% of the seafood
market, contain a mean mercury level of approximately
0.1 mg/g. Methylmercury has been used as a
fungicide on seed grains and is also an industrial
waste. When grain accidentally treated with a mercury
fungicide was eaten by people in Iraq during a
famine in the 1970s, mercury poisoning occurred in
hundreds of people.18
http://aappolicy.aappublications.org...;108/1/197.pdf