Dioxin levels in gulls detailed in study

Steven Warburton / The Independent (Brighton, Ontario) 24may00

Warning:

Eating Lake Ontario fish could be hazardous to your health.

At least that's one of the contentions of 1999 ENSS graduate, Emily Chatten, who made a presentation on the legacy of the Scotch Bonnets herring gull at the Presqu'ile Brighton Naturalists annual meeting last week.

Chatten, who is now a University of Waterloo environmental studies student, says her presentation on Scotch Bonnet herring gulls actually stemmed from a project she worked on at ENSS.

"Our biology teacher wanted us to do an ecology project on a local problem," she says. "A lot of kids chose things like zebra mussels but I decided to go with the gulls because they represent a local animal colony and I wanted to focus on the changes in their endocrine disruption and hormonal imbalance due to industrialization."

Chatten says that Scotch Bonnet herring gulls today have up to 25 million times the dioxin level in their bodies than is contained in Lake Ontario.

"Dioxin is the most toxic substance created by man," Chatten says. "It's largely a by-product created when making chlorine products or while burning chlorine."

 Dioxin was a contaminant in Agent Orange used in the rainforests during the Vietnam war, Chatten adds.

"It stripped the leaves off the trees so that people couldn't hide," she says. "Now we're seeing people in Vietnam being born with strange deformities and immunal disfunctions."

Chatten says that dioxin is seeping into Lake Ontario and, consequently, its food chain Dioxin molecules stick to algae, which, in turn, is eaten by smelt. The smelt are then eaten by another fish, or a gull. The danger is that with gulls and humans being on the end of the same food chain, there is a chance that humans could suffer the same deficiencies.

In fact, Chatten points to some studies which show that women who eat large amounts of Great Lakes fish while pregnant have a greater risk of having children with developmental problems such as immune disorders and attention deficit disorders."

Chatten's conclusion is largely backed up by officials like Dr. Glen Fox, contaminants effects specialist for Canadian Wildlife Services and Dr. David Carpenter, a medical doctor at the University of Albany.

"The evidence is quite strong that mothers who eat a lot of Lake Ontario fish will pass abnormalities on to their children," says Dr. Carpenter. "There's an ongoing study where we selected a bunch of women who were giving birth and divided them up into three categories, those who ate a lot of Lake Ontario fish, those who ate some Lake Ontario fish, and those who ate no Lake Ontario fish."

Carpenter says that abnormal developments in nervous system reflexes could be detected as early as the first 48 hours of life in the babies of Lake Ontario fish-eating mothers.

"If you shine a bright light in the eye of a new baby, they will jump and blink," says Carpenter. "If you keep shining the light in their eyes, they will eventually grow accustomed to it. But these infected children never did grow accustomed to it."

Carpenter says that these children are now about seven and eight and are still the cause of study.

"They've remained abnormal," he says. "Studies are showing that they are about six points below the average IQ level."

But Dr. Fox says that although the reproduction of gulls on Scotch Bonnet Island is normal, he does say that the immune function of prefledglings is suppressed by 30 to 40 per cent and that there are abnormalities in their reproductive tracts.

"Unfortunately, there have been no investigations of neurobehavioral development in gulls or other wildlife in the basin, that I am aware of," says Fox. "Mostly because we do not have the kinds of tools and background information that there is for this kind of testing in humans."