METALS - Marine Pollution: What Everyone Needs to Know - page 94

exposure, and recommends that schools and parents not serve
it. The group also says children under 55 pounds should limit
“light” tuna to one meal, once a month and twice a month for
children over that weight. They also recommend that no child
should eat tuna every day. The European Union recommends
that pregnant or breastfeeding women not eat tuna more than
twice a week, while the US Food and Drug Administration
says they should avoid shark, swordfish, or king mackerel,
but that some tuna should be included in their diet. Some feel
these guidelines are out of date and stricter rules are needed
to avoid the risk that even low levels of Hg could lead to prob-
lems in fetuses and young children.
What are the trends in metal pollution?
Overall decreases are seen, but improvement is very slow. Trace
metals have been monitored in the Baltic Sea waters and biota
with mixed trends. While the Baltic Sea remains much more
contaminated than ocean waters, a slow decrease in dissolved
Cd and Cu has been observed in many sites over a decade, but
this was attributed to increasing hypoxia due to eutrophication,
which precipitated the metals, rather than to an actual decrease
in the metal contamination. Decreasing Pb was attributed to
the switch to unleaded gasoline. Sediments, however, were still
highly contaminated. Mercury and zinc also showed downward
trends. Various fish species used for human consumption showed
similar decreases. Declines in concentrations of Cd and Hg were
seen in all the fish species studied by Lucyna Polak-Juszczak.
Similarly, Pb in the livers of a number of fishes used for human
consumption showed a significant declining trend.
What can be done to reduce metal pollution?
Metal pollution can be reduced by reducing inputs in the first
place, and by remediating areas that have already been con-
taminated, which is the focus of the Superfund program of the