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Wed 3 Mar, 2010 01:20 pm
Herbicide turns male frogs female?
A study shows that male frogs exposed to the herbicide atrazine can make a startling developmental U-turn, turning female so completely that they can mate with other males and lay viable eggs.
The study will focus new attention on concerns about atrazine, which is applied to an estimated 75 percent of American cornfields and is commonly found in U.S. rivers and streams. Its manufacturer, the Swiss agricultural giant Syngenta, says the product is safe for wildlife and for the people who are exposed to small amounts of it in drinking water.
In recent years, however, some studies have seemed to show that atrazine can drive natural hormone systems haywire in fish, birds, rats and frogs. In some cases, male animals exposed to the chemical developed female characteristics.
The new study led by Tyrone Hayes, a professor at the University of California at Berkeley, was published in the Proceedings of the National Academy of Sciences. It showed an even starker transformation: Among a group of male African clawed frogs raised in water tainted with atrazine, he said, a fraction grew up to look and act like females.
"Ten percent of the chromosomal males become completely, functionally female," Hayes said in a telephone interview. "They can lay eggs (and) they mate."
The findings run counter to the U.S. Environmental Protection Agency's pronouncement in 2007 that atrazine does not cause problems in amphibian development. But last fall, the EPA said it would ask a panel of scientists to examine more recent studies.
Oops, I thought this thread was about France.
could there be more than one side to this story?
The EPA, the Australian government, and the World Health Organization have all looked at atrazine’s effects on endocrine systems and given atrazine a clean bill of health.
Most recently, the State of Minnesota conducted a thorough review of atrazine, and in a January announcement said, “The review finds that atrazine regulations protect human health and the environment in Minnesota.” Atrazine is critical for family farms The EPA estimates the loss of atrazine would cost corn growers $28 an acre in lost yields and substitutes, and the total negative impact on corn, sorghum and sugar cane growers in the U.S. would exceed $2 billion per year.
All studies are not created equal The soundness of a scientific study hinges on its transparency and reproducibility. Do its procedures and results stand up to review by independent scientific peers and regulatory agencies? Can the study be reproduced with the same findings? This approach safeguards the scientific community, regulators, industry and the public from questionable results.
In testimony before the Agriculture and Rural Development Committee of the Minnesota House of Representatives (February 16, 2005), Anne E. Lindsay, former deputy director, Office of Pesticide Programs, US Environmental Protection Agency, detailed the elaborate and meticulous scientific process required for pesticide registration.
She described at length the painstaking process EPA followed before recommending the re-registration of atrazine for use in American agriculture. She noted that EPA "reaches its conclusions through a systematic, objective evaluation of all relevant information. She noted that each step of the process uses scientifically peer-reviewed, documented procedures."
Lindsay testified that EPA looks "closely at every study to determine whether the results are scientifically sound," and that it insists on record retention and full data reporting. She stated that to review these studies, EPA follows "published, peer-reviewed Standard Evaluation Procedures."
Despite EPA's diligent investigative process, a legal and political attack has been launched against atrazine, relying on a handful of studies which, by objective scientific standards, offer questionable conclusions.
Regarding comments on frogs and atrazine A new set of observations released yesterday in Proceedings of the National Academy of Sciences claims effects of atrazine on amphibian development but raises questions about the integrity of the assessments’ experimental design.
The study has many shortcomings that undercut its usefulness, including its inconsistency with prior findings by the author. Two other in particular are: 1) the use of only one dose level of atrazine, when almost all studies used to assess the effects of substances for regulatory purposes are conducted at more than one concentration to validate when and if a predicted response happens consistently and; 2) the failure to use a positive control " a basic requirement of this kind of study. Positive controls confirm that the procedure is competent in observing the effect.
One study among many For 50 years, atrazine has been used safely in agriculture with no effect to amphibians, fish, birds and other wildlife at concentrations found in the environment"a fact that is supported by numerous scientific studies. Several recent studies add to the collection of 6,000-plus that support atrazine’s safety to amphibians. Technical experts can review the following:
Atrazine is safe to use Atrazine is a legally approved and heavily regulated product after exhaustive research including nearly 6,000 studies which determined it is safe for use as labeled. There is no other crop protection product that has received more examination than atrazine. Based on sound science and rigorous review, the EPA determined that atrazine poses "no harm that would result to the general U.S. population, infants, children or other ... consumers."
I don’t know the current state of this “issue” but would like to make a couple of points. Just because I find the situation funny.
The powerful agricultural and chemical industies should make you at least stop and consider that maybe THEY performed studies whose results would please these lobbies.
This quote coming from Minnesota begs the question does the economic loss trump science the science.
“Atrazine is critical for family farms The EPA estimates the loss of atrazine would cost corn growers $28 an acre in lost yields and substitutes, and the total negative impact on corn, sorghum and sugar cane growers in the U.S. would exceed $2 billion per year.
“Several recent studies add to the collection of 6,000-plus that support atrazine’s safety to amphibians. “ sounds good but who did them and how were they done.
For years the EPA had no problem with DDT, that worked out well!
Most humorus to me
How come the times when the EPA comes down on the side of the consumer or the environment it is just an orginazations of nuckle-dragging, Al Gore loving, hippie freaks but when it somes down on the side of businesses with a vested interest in the decision the EPA suddenly is seen to look "closely at every study to determine whether the results are scientifically sound," and that it insists on record retention and full data reporting.”
So since it looks like I should take the EPAs word on this then I guess I also have to accept CO2 as a pollutant, global warming, and man having a significant impact on global warming too don’t I?
Use it / don't use it I couldn't care less. I just thought it funny.
There was a time when cigarettes were actually advertised to be good for you.
Who are we to trust? Who should we listen to?
This kind of crazy-making stuff drives me nuts . . .
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