lakes turning turtles into turtlettes
By Martin Mittelstaedt
The Globe and Mail
April 28, 2004
TORONTO -- Canadian researchers studying wildlife on the
Great Lakes have found sexual abnormalities in male snapping
turtles, with penis size diminished and some males able
to produce egg yolk protein, a capability normally found
only in females.
The research, conducted by biologists with the Canadian
Wildlife Service of Environment Canada, is part of a growing
body of international evidence indicating that many species
are suffering from exposure to so-called gender-bending
chemicals, industrial pollutants that have been found
to mimic sex hormones.
These changes so far have been observed most in fish,
but researchers have noted genital abnormalities in other
species ranging from Florida panthers to alligators.
The turtles with abnormal penis size were found in Ontario:
in the Detroit River near Windsor, the St. Clair River
near Sarnia, and the harbour of Wheatley, a small fishing
community on Lake Erie. All three sites are pollution
Snapping turtles in cleaner environments, such as Algonquin
Park and in a marsh near Midland, Ont., lacked the abnormalities.
The turtles that produced egg yolk protein were found
around Wheatley. That protein is normally "only produced
by females when they're laying eggs," said Kim Fernie,
a biologist with the wildlife service, who was part of
the team conducting the research. "You would not
expect to find it in a male turtle."
Additional work by the scientists on herring gulls discovered
the egg protein in some male birds along the Detroit River.
Female reproductive characteristics in male turtles and
birds are a sign of contact with chemicals that act like
female sex hormones.
More than 50 synthetic compounds have been found to affect
hormone systems, among them dioxins, polychlorinated biphenyls,
pesticides and some plastics.
Sarnia has Canada's largest concentration of petrochemical
plants; the Windsor-Detroit area is heavily industrialized.
Wheatley is in an agricultural area.
Young turtles showed other biological abnormalities,
such as impaired thyroid function, at all three sites.
Researchers say they don't know yet which compounds caused
the developments they observed.
"As this is relatively new, we don't know what is
causing that yet," said Laird Shutt, a toxicologist
with the wildlife service who conducted the research on
Ms. Fernie said her results are preliminary, and she
has done more field work trying to verify the extent of
the turtle abnormalities. But the newer samples are being
analyzed, and results are not expected until next year
because of laboratory backlogs at Environment Canada's
"We did find these changes in the first year, but
is that going to be consistent over multiple years or
not, I don't know at this point," she said.
Environment Canada has issued a summary of the research
on its website but has not publicized the findings.
Mr. Shutt said the levels of egg yolk protein he observed
in male birds were not high enough to affect their chances
However, environmentalists said the research is worrisome
because chemicals powerful enough to affect hormones are
a potential health threat.
"As soon as you're disrupting hormone systems, there
is a chance of cancer; there is a chance of other diseases,"
said Bailey Mylleville, a spokesman for Great Lakes United,
an environmental group based in Buffalo.
In the turtle research, Ms. Fernie said she calculated
penis size by measuring the distance between the reptile's
shell and anus, and from that made an estimate of penis
She would not say how much the organs were reduced in
size. Taking actual penis measurements would have required
killing the turtles and opening up their shells.
The research also found excessive production of some
liver enzymes in young snapping turtles and adult herring
gulls from the Detroit River area.
They said high production of the enzymes occurs when
animals are exposed to dioxin-like substances.
At Wheatley, the researchers were unable to find any
signs of reproductive activity by the snapping turtles.
Along the St. Clair River, scientists found less hatching
success than at the non-polluted sites.
Gulls from the Detroit River showed impaired immune systems.
There were also high numbers of dead gull embryos in nests
along the Detroit River and in western Lake Erie, compared
to cleaner sites, and a single male bird with what the
Environment Canada research summary called a "significantly
feminized reproductive tract."