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article imageChemicals turning male fish into female fish in Alberta rivers

By Stephanie Dearing     Jul 30, 2010 in Environment
Calgary - University of Calgary researchers who have been monitoring fish in two southern Alberta rivers raised an alarm Thursday, saying a 'chemical cocktail' is turning male fish into females.
In a news item released by the University of Calgary, the researchers say they found increased numbers of female fish downstream from communities, and tests revealed a slew of chemicals that affect reproductive functions in animals by mimicking hormones. Testing for 28 chemicals, the researchers found "... synthetic estrogens (birth control pill compounds and hormone therapy drugs); bisphenol A, a chemical used in making plastics; and certain types of natural and synthetic steroids that are byproducts of agricultural run-off and cattle farming." One of those agricultural byproducts is a growth hormone used in the livestock industry.
The research focused on two rivers in the south Saskatchewan River Basin in Alberta. The paper, Presence of natural and anthropogenic organic contaminants and potential fish health impacts along two river gradients in Alberta, Canada is published in the journal, Environmental Toxicology and Chemistry. The two researchers, Lee Jackson and Hamid Habibi concluded "The current study demonstrates that organic contaminants, many with estrogen-like activity, are distributed over hundreds of kilometers throughout the South Saskatchewan River Basin and not just downstream of major point-sources. Therefore, many activities within these basins impact water quality in the South Saskatchewan River Basin and affect endemic longnose dace populations."
The Globe & Mail reported that the safety of the water is now being questioned. The chemicals found in the fish have been found in association with human cancer, although a causative relationship has not yet been confirmed. However, Jackson cautioned that more research is needed to confirm that hormone mimicking chemicals do cause cancer.
The researchers looked at the Red Deer and the Oldman Rivers for their study, concentrating on the longnose dace, a minnow found in the rivers. Jackson said “What is unique about our study is the huge geographical area we covered. We found that chemicals – manmade and naturally occurring – that have the potential to harm fish were present along approximately 600 km of river. The situation for native fish will likely get worse as the concentration of organic contaminants will become more concentrated as a response to climate change and the increase in human and animal populations."
Habibi said the most interesting results were found downstream from two communities. “... we saw a significant increase in a specific protein marker for the presence of compounds with estrogen-like activity in areas downstream, south of Fort Macleod and Lethbridge. Our results showed females make up 85 per cent of the population of longnose dace. In the upstream locations, females comprise 55 per cent of the population.”
The research only concerned longnose dace, so determining the effects on humans and other animals remains a topic for future study, something Habibi and Jackson are already engaged in. The pair are "studying the impact of environmental contaminants with hormone-like activity in Southern Alberta rivers and lakes."
The future of the longnose dace is uncertain in the rivers studied, although it is anticipated the feminization of the fish will impact negatively on reproduction.
A recent American study tracking pharmaceuticals released from treated urban waste water found the contaminants are not being caught by the water treatment process. American scientists link the antidepressants, veterinary hormones and other chemical residues in the water to the feminization of fish, reported UPI. Scientists also presume the chemicals are making their way back into the drinking water system.
No one knows what impact the chemicals might have for people, but that hasn't stopped some consumers from switching their diets to ensure they are consuming less hormones and chemicals. But consumers are not the only ones choosing to make changes without the science to support the decision. The Republic reports that 300 hospitals in the United States are not going to serve their patients foods containing antibiotics or hormones. Some, like the Swedish Convent Hospital, are offering their patients natural or organic foods.
The President of Health Care Without Harm, Gary Cohen, said “In order to reduce the chronic disease burden of Americans and to contain health care costs, we need to eliminate toxic chemicals that have trespassed into our bodies and into our lives. There is a wave of real concern in the health community about the link between the widespread exposure to chemicals and the overwhelming epidemic of chronic disease burdening the U.S. health care system.”
Health Care Without Harm works to help hospitals reduce the amount of environmental harm associated with the delivery of health care around the world.
In Canada, Environmental Defense has been calling attention to the rise of chemicals and hormones in the environment, lobbying for changes to protect human health through their campaign, Toxic Nation.
More about University calgary, Gender bending, Chemical pollution, Water safety
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