London Free Press
WINDSOR -- While levels of PCB contamination
in Lake Erie have dropped in recent years, the southwestern
end continues to have far higher contamination levels
than anywhere else in the lake, say Environment Canada
That area includes the lake's main tributary, the Detroit
River, and all the smaller streams, creeks and channels
that flow into the river, Chris Marvin said at a conference
at the Great Lakes Institute for Environmental Research.
"Studied over a decade and even dating
back as far as the early 1970s, there's no question the
concentration of PCB contamination has been in marked
decline," Marvin, a research chemist, said yesterday.
"Part of the reason can be traced to the ban on PCBs in
the 1970s, but there's also been a more responsible stewardship
regarding PCBs from the general public and from industry,
which has also contributed to the decline."
PCBs, or polychlorinated biphenyls, are a family of 209
chemical compounds no longer made in Canada or the U.S.
High exposure can result in liver damage and can sometimes
affect the nervous system and cause numbness, weakness
and tingling in limbs.
The higher concentration of industry surrounding the western
basin of the lake has a direct impact on contamination
levels, which decrease as samples are taken further north
and east, said Scott Painter of Environment Canada.
"And those concentrations have been steadily declining
for the past 30 years," said Painter. "We're close to
achieving threshold levels so there's no question we are
going in the right direction."
Almost 20 speakers from several Canadian and American
agencies were expected to speak at the conference.
"Collectively, various agencies have spent more than $100
million trying to clean up contamination in the lakes,"
said Doug Haffner, director of the Great Lakes Institute.
"We're hoping by the end of this conference we'll have
some idea if we're succeeding and where additional work
needs to be done."
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