BIOACCUMULATION AND BIOMAGNIFICATION - Marine Pollution: What Everyone Needs to Know - page 150

of meHg. However, large carnivorous fish that live longer have
the highest levels, because they have had more time to accu-
mulate it. These large fish (swordfish, shark, king mackerel,
and tuna) pose the greatest risk.
The greatest concern about Hg exposure is for a develop-
ing fetus. As seen in Minamata, some women who showed
no signs of poisoning gave birth to children with severe brain
damage. This is because meHg readily crosses the placenta.
It can also be passed through breast milk to infants. This is
of particular concern, because young children are more sus-
ceptible to Hg toxicity and the brain may be more affected as
it develops. There is a correlation between prenatal exposure
to Hg and decreased performance of infants and children on
neurobehavioral tests including tests of attention, fine motor
function, language skills, visual-spatial abilities, and memory.
While the danger of Hg poisoning may seem like a good
reason to avoid consuming fish, the benefits of eating fish may
outweigh many of the risks. Fish are high in protein, low in
saturated fats, and contain important nutrients such as heart
healthy omega-3 fatty acids. Eating fish reduces the risk of
heart attacks, lowers blood pressure, and improves arterial
health. So it is a matter of choosing the right fish to eat.
The US Environmental Protection Agency (EPA) and the
US Food and Drug Administration (FDA) have issued con-
sumption advisories for certain groups of people. They advise
women who may become pregnant, pregnant women, nursing
mothers, and young children up to age six is avoid fish high
in Hg and limit the amount of fish consumed each week. They
advise them not to eat shark, swordfish, king mackerel, or tile-
fish at all because they contain high levels of Hg (>1 ppm), but
to eat up to 12 ounces (two average meals) of fish and shell-
fish that are low in Hg per week. Children should only eat
six ounces of fish. Low Hg fish and shellfish include shrimp,
canned light tuna, pollock, salmon, and tilapia. Albacore
tuna contains moderate amounts of mercury. The EPA and
FDA advise eating only 6 ounces of albacore tuna a week and