WINDSOR STAR (Ontario) 29 April 04 River toxins trick turtle hormones: Pollution scientists' warning: Do not eat Detroit River fish (Doug Williamson)
Think twice before eating fish caught in the Detroit River, advises a Windsor scientist participating in a federal study on the "feminizing" of male snapping turtles because of industrial pollutants in the food chain.
"I see people fishing in the Detroit River all over the place. I personally would not," said Rob Letcher, a scientist at the Great Lakes Institute in Windsor who studies the effect of chemicals on aquatic organisms.
The turtles' diet of fish and frogs is contaminated by gender-bending pollutants like PCBs and dioxins, scientists believe. The chemicals, in effect, mimic sex hormones and disrupt the turtles' endocrine systems.
Letcher and fellow GLI researcher Ken Drouillard are key participants in the Environment Canada study of snapping turtles in the St. Clair River, Detroit River and Wheatley Harbour -- three areas known for chemical contamination.
The scientists said the study does not indicate danger from drinking water because the chemicals are in the river bottom sediment.
"We have very good water here," Letcher said. "Dietary consumption, I would say, is where the source is."
Some male turtles have become "feminized," showing abnormalities such as diminished penis size and ability to produce egg yolk protein, normally a female turtle trait, the researchers said. Turtles from a control group in Algonquin Park, where there is no such contamination, do not show these changes.
"People that eat fish on certain areas of the Lake Huron-Lake Erie corridor obviously are putting themselves at higher risk because they're participating in the food web, just as any other creature that would eat fish -- a fishing bird, a herring gull, or a snapping turtle," Letcher said.
"To say that it's chemicals is probably a viable answer because there's lots of endocrine-disrupting chemicals in the Great Lakes, particularly around here," he said, cautioning the research is not completed.
People should be concerned and not just for the turtles, agreed John Jackson, past president of Great Lakes United, a bi-national coalition of environmental groups based in Buffalo, N.Y.
"There are a lot of people who eat fish and wildlife," Jackson said from his home in Kitchener. "They're taking in those contaminants."
For eight months, Letcher and Drouillard have been analysing tissue and blood samples from local snapping turtles and sending the data to other scientists. The final report is due to be completed next month and presented to a conference in Oregon in November.
"I would be very careful about consuming fish from the Detroit River," he said. "With the Detroit River, pollutants are heavily associated with the sediment. I would be very concerned about eating fish from the Ambassador Bridge down to the end of Grosse Ile.
"Obviously this is an urban area and there's a lot of known outfalls of contamination."
He said fish from Lake St. Clair and Lake Erie are less of a concern, although he suggested people follow Ontario guidelines on eating fish.