Pollutant level rising in Great Lakes
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By Gary Wisby
Published June 30, 2004
Herring gull eggs collected from nests along the Great
Lakes are contaminated with a pollutant that could be
as bad as PCBs.
Moreover, levels of BDEs -- brominated diphenyl ethers
-- are rising, and are highest in eggs collected near
Chicago and other big cities.
Environment Canada, a government department, has been
sampling the eggs every spring since 1974 at 15 sites
on the Great Lakes.
Since then, of the more than 100 chemicals detected,
most have decreased by 50 percent or more, and some as
much as 95 percent.
Only one -- BDEs -- is on the increase, said Chip Weseloh,
the wildlife biologist who heads the egg-testing project.
BDE levels aren't considered high enough to harm wildlife,
but if the trend continues, the pollutant will become
the main contaminant in gull eggs in 10 to 15 years.
Eggs collected near Chicago and Milwaukee have the highest
BDE readings, followed by Toronto Harbor.
"It's often worse in industrial areas," Weseloh
BDEs are flame retardants found in plastics like computer
casings or in foam rubber furniture. They are similar
to PCBs, carcinogenic chemicals once used in insulating
fluids of electrical systems.
BDEs' harmful effects were first discovered in Europe
and showed up in this country 10 or 15 years ago. It's
likely they will be banned, as PCBs were in 1978.
They probably get into Lake Michigan by off-gassing from
furniture or in effluent from manufacturers that use the
Herring gulls pick up BDEs through the herring and other
fish they eat.
Why this bird as an indicator?
"It's nonmigratory," Weseloh explained. "If
we find stuff in its eggs, it comes from the Great Lakes.
If it were a bird like the ring-billed gull, the stuff
could be from here or Florida where it winters."