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Winnipeg Free Press: Canada

The Canadian Press - ONLINE EDITION

Researchers say skewed sex ratio of fish in Alberta rivers raises red flags

By: Shannon Montgomery, The Canadian Press

29/07/2010 8:56 PM

CALGARY - Alberta researchers say gender-bending fish swimming in the province's southern rivers raise serious questions about whether the water is safe for people to drink.

Two University of Calgary professors have been studying how a small species of minnow reacts to a wide variety of hormone-altering chemicals detected in several rivers.

They found sexual changes both in the wild populations of the fish and under controlled lab experiments with the same chemicals, said co-author Hamid Habibi.

He said while it's not known whether the levels are high enough to hurt humans, there is a possible risk the chemicals could increase cancer rates or developmental abnormalities.

"We think there's a health concern," he said Thursday. "We'd like to be able to predict these things and reduce that kind of risk."

In some locations, female fish accounted for as much as 90 per cent of the minnow population, far higher than the normal 55 to 60 per cent.

At many of the sites studied, male fish showed elevated levels of a protein normally high only in the blood of females. Other areas have produced male fish with female eggs in their testes.

Habibi and co-author Lee Jackson found a large variety of chemicals that affect hormones in the water. They include synthetic estrogens, such as the birth control pill and bisphenol A — a chemical used in making plastics — as well as agricultural byproducts.

The disturbances in fish populations were greater downstream from cities than upstream and were most notable around several major cattle feedlots.

One area of high concentration was interrupted by a normal region where the river is joined by several tributaries from Waterton National Park.

The researchers managed to replicate many of the changes in a lab environment by combining the chemicals in the same ratio as found in the river.

They also discovered that while a single chemical might affect a fish one way, the combined effect with another chemical might be much greater than expected.

In one case, two chemicals might each have a one-fold effect on a fish, while in combination the effect might be nine times bigger.

"The potency of these chemicals improves significantly if they are present in a mixture. That is new information," said Habibi.

"Which means some of the data used by Health Canada and EPA (the Environmental Protection Agency in the United States) may need to be revised, because they're based on individual studies for those chemicals."

Jackson said most wastewater treatment plants don't get rid of many of the chemicals.

The researchers have partnered with the City of Calgary to begin work at a new treatment plant investigating how engineering can keep the chemicals from flowing back into the water.

He said it's too early to tell whether the current levels in water might have anything to do with a rising trend of cancers that are under hormonal control, but he added that a possible link should be studied.

"I think we need to look at this a little more carefully and ask, what is the message the fish are telling us," he said.

"If the fish are showing bent genders and people are drinking the same water ... we need to try to evaluate that risk."

Part of the research is to be published in the journal Environmental Toxicology and Chemistry.


What does this have to do with Cranbrook?


With a few clicks of a mouse and the use of Google it is very easy to come up with countless peer-reviewed scientific studies of the effect of treated wastewater on our environment. In the vast majority of these studies the effect of introducing wastewater to our natural water systems and on their supported wildlife is one of negativity. Scientists are frequently noticing gender changes and other deformities to the wildlife that has been exposed to the wastewater.

Cranbrook, like most communities, is unable to control what gets sent down the drains and into our sewage system. Wastewater typically contains a mixture of natural and synthetic xenobiotics, household and agricultural chemicals, pharmaceuticals, hormones, and other compounds, many of which remain unidentified. Wildlife is thus being exposed to complex, fluctuating mixtures of contaminants that may act in various ways and that may induce combination effects via the same or different mechanisms.

Just because we send Cranbrook's effluent 9km from where we live shouldn't mean that we act in a NIMBY manner and ignore what its potential effects are on the environment and the life that lives in, and around, the Kootenay River. Some other communities have been giving a lot of thought and effort in removing most of the potential pollutants from their wastewater before it is returned, in some fashion, back into the environment. Cranbrook's new plan is one of screening, simple disinfection, and aeration before the effluent is sprayed over the fields.

Right now would you want your/our effluent returned to the Cranbrook watershed that supplies your/our drinking water?

Perhaps Cranbrook's effluent is closer to the human food chain than we imagine. Cattle are raised on crops grown using the effluent. The cattle are drinking the effluent and even being sprayed with our wastewater as they forage in the spray fields. Is it time when we need to ask our meat suppliers where, and how, their supply of beef is being raised? I'm not sure that I particularly relish the thought of potentially introducing natural and synthetic xenobiotics, household and agricultural chemicals, pharmaceuticals, hormones, and other compounds into my body as I chow down on my barbequed beef steak.