Researchers Find Gender-Bending Chemicals In Two Alberta Rivers – for Aug. 16, 2010

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Scientists have found several chemicals in the Oldman and Red Deer rivers that alter the sexual development of fish and may affect the brains of human infants and fetuses – and some of the substances originate on farms.

The University of Calgary researchers collected water samples and long-nosed dace (minnows that generally spend their whole lives in one part of the river) from eight spots between Penhold and Drumheller on the Red Deer and eight points on the Oldman from Olin Bridge above the reservoir to Highway 36. They tested the water for 28 chemicals, most of them known or suspected to have hormonal effects.

Natural and synthetic estrogens were found in all the water samples with higher levels below cities and towns, but natural hormones were also high in regions of intensive agriculture. The scientists also found bisphenol A (BPA), used in PVC and polycarbonate plastics, in some of the samples. There was also zeronal, the active ingredient of some cattle growth implants, plant steroids, and steroids linked to cholesterol, one of which is used as an indicator for fecal contamination.

At every site but one, male fish had detectable levels of a female hormone, vitellogenin, which is involved in egg production. Downstream of Lethbridge and Fort Macleod, the sex ratio of the fish was skewed, with 85 per cent females instead of the 55 per cent above the towns.

Water returned to the rivers from waste water treatment plants is the major source of natural hormones and synthetic estrogens as well as cholesterol derivatives. These chemicals likely come from human waste as the synthetic estrogens are used for birth control and hormone therapy. Natural hormones and cholesterol residues may have come from livestock. Some water samples contained zeranol, the active ingredient in Ralgro, suggesting cattle manure is being washed into them.

The trouble is that estrogens and estrogen-like chemicals don’t only harm fish – they’re swimming in our drinking water. Each chemical may be at low concentrations that are well below harmful levels, but safe levels for an adult may not be safe for an infant or a fetus, and at specific times, an infant’s or fetus’s growing brain can be extremely sensitive to very low levels of estrogenic compounds. The levels of zeranol were high enough to affect a fetus, according to researcher Hamid Habibi. And, in complex mixtures, the chemicals may be more potent.

Many sources

Habibi is quick to point out that the research is not an effort to demonize farmers. “We know many of the materials we use every day can cause problems in the environment,” he says. “Detergents, flame retardants, plastics and pharmaceuticals all break down to produce harmful chemicals. Some herbicides break down into chemicals suspected to have hormonal effects. But, it’s not a farm problem, it’s a problem of our whole society. We need to deal with it as a society.”

Habibi, who is director of the new Institute of Environmental Toxicology at the University of Calgary, wanted to confirm that problems in the South Saskatchewan River Basin are similar to those in other areas. “This information is not new, it’s new for this area,” he says. “We have to first define the problem and identify issues, then bring people together to address these problems. We’re working to understand the mechanisms of endocrine disruption by these chemicals and find the safe levels as well as developing technology to remove them.”

Farmers must do their part by following best management practices for manure and herbicide applications and cattle operations, says Habibi. Barriers and setbacks to prevent run-off entering waterways or ditches are essential.

Habibi says farmers, as stakeholders in ensuring the rivers are protected, can be among those directing the work of his institute as well as that of Advancing Canadian Wastewater Assets, a new research facility at Calgary’s new waste water treatment plant at Pine Creek.

Habibi wants to see government and companies that produce chemicals and pharmaceuticals to lead the funding of research into these issues. There’s also a huge need for investment in waste water treatment. In 2003, the Canadian Wastewater Treatment Association estimated an investment of $37 billion was needed to bring facilities across the country up to par, but that figure didn’t allow for growth or new technology.

“We need knowledge-based, efficient and high-tech systems,” Habibi says. “Some of these chemicals have bad effects on our children and grandchildren.”


“But, it’s not a farm problem, it’s a problem of our whole society. We need to deal with it as a society.”



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