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Common Weedkiller Turns Male Frogs Into Females
WASHINGTON - Atrazine, one of the most commonly used and controversial weedkillers, can turn male frogs into females, researchers reported on Monday.
File photo shows a frog at the Besancon Natural History Museum. One of the most common weed-killers in the world, atrazine, causes chemical castration in frogs and could be killing off amphibian populations worldwide, a study published showed.
(AFP/File/Jeff Pachoud) The experiment is the first to show such complete effects of atrazine, which had been known to disrupt hormones and which is one of the chief suspects in the decline of amphibians such as frogs around the world.
"Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults," Tyrone Hayes of the University of California Berkeley and colleagues wrote in the Proceedings of the National Academy of Sciences.
The chemical had been shown to disrupt development and make frogs develop both male and female features -- termed hermaphroditism. This study of 40 male frogs shows the process can go even further, Hayes said.
"Before, we knew we got fewer males than we should have, and we got hermaphrodites. Now, we have clearly shown that many of these animals are sex-reversed males," Hayes said in a statement.
"Atrazine has caused a hormonal imbalance that has made them develop into the wrong sex, in terms of their genetic constitution."
Syngenta AG
"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," the company said in a statement.
The Proceedings is a peer-reviewed journal, meaning that papers it publishes have been screened for obvious flaws.
EFFECTS ON HUMANS?
Whether the effects translate to humans is far from clear. Frogs have thin skin that can absorb chemicals easily and they literally bathe in the polluted water.
The European Union banned atrazine in 2004. The finding may add pressure to the United States to more closely regulate the chemical, used widely in agriculture.
"Approximately 80 million pounds (36,000 tonnes) are applied annually in the United States alone, and atrazine is the most common pesticide contaminant of ground and surface water," the researchers wrote.
"In fact, more than a half million pounds (220 tonnes) of atrazine are precipitated in rainfall each year in the United States."
The U.S. Environmental Protection Agency said in October it was reviewing the health impacts of atrazine.
Hayes and colleagues studied 40 African clawed frogs, keeping them in water contaminated with 2.5 ppb (parts per billion) of atrazine. The EPA's current drinking water standard is 3 ppb.
"Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs," the researchers wrote.
"Regardless of the mechanism, the impacts of atrazine on amphibians and on wildlife in general are potentially devastating," they wrote.
"The negative impacts on wild amphibians is especially concerning given that the dose examined here (2.5 ppb) is in the range that animals experience year-round in areas where atrazine is used as well within levels found in rainfall, in which levels can exceed 100 ppb in the Midwestern United States," they added.
(Editing by Sandra Maler)
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14 Comments so far
Show AllUmm, so does that mean when a princess kisses a frog she gets another princess instead of a prince?
All kidding aside, this does make one wonder what the planet will look like in another 100 years. How many animals that we take for granted now, wont be there for future generations.
If it affects people, can they still serve in the army?
I think I see another "don't ask don't tell" deal coming up.
hoo boy...even the phrase 'future generations' becomes, well, less than a given, whatever you want to call that...
unfortunate to be a chemical creature in a chemically devastated world...
oh, wait...me, too!
can we stop now? how about on September 22, 2012?
tip of the hat:
and you knew who you were then
girls were girls and men were men...
those were the days!
I don't see why more females would cause population decline. If frogs are like chickens, one male can serve many females, population might well go up.
as long as he's male...whoops! too late...
Devoish,
I understand that there are some animals that have been shown to change sex, if one sex is in short or nonexistant supply. What happens if 40 male frogs are kept together in water not contaminated by atrazine? Is there any differentce in the result? The study was not linked, was there a control group?
Devoish - who would be inclined to ban first, answer questions later.
Gorsegrower: nobody really knows the answer to that, but while the eggs may be viable, that does not necessarily mean that after they develop, these animals will also be able to reproduce. Studies show populations often crash after a few generations, and it is generally believed to be due to multi-generational reproductive issues. The fact is that much more research needs to be done, but the EPA and government have been dragging their feet in studying the effects of endocrine disurptors for over twelve years. They were first informed of the problem and likely consequences in 1993, so in reality, this is just another case where corporations have been and are calling the shots.
One of the things that really irritates me about many press articles about endocrine disruption is the oft-repeated claim that goes something like: "we see these bizarre outcomes in animals, but we don't know if it happens in humnas." Let me be as clear as I possibly can: they are not looking. They don't want to look. And if they did look, they would find the answer is yes, the same effects happen in humans, and have been happening for over seventy years.
I have researched and written about the human effects of endocrine disruptors extensively, but few want to listen, even people who are so affected, namely many intersex and transgender folks. Probably much of the whole LGBTIQQ spectrum is a direct consequence of the vast chemical experiment that the corporations have been running for the last century. And the wider public doesn't dare consider the possibility that these people might be deserving of a little bit more compassion and understanding, not to mention civil rights, than they have had up to the this point.
If anyone is interested in this topic though, I recently started a blog at: http://www.fearofapinkplanet.blogspot.com. I also link to all my papers, although the link is broken at the moment. Should be fixed later today.
might be desirable for males of the human species to have more feminine traits or at least less macho ones...
Finally! A REAL "CURE" for homosexuality.
Quick - call what's his name ... the man who claims he can make gay people "straight".
Boy, if he gets wind of these findings, he'll be dousing his charges with ATRAZINE, heating them up for a few hours to accelerate the process, and ... VOILA! INSTANT SEX CHANGE!
I'm impressed the males became egg-laying females - and the eggs are for REAL!
Wait a minute. What about us girls? Which chemical works for us, changing us into functioning males?
It figures! Even mother Nature is sexist, giving the men a way to change their sex and leaving the women behind with nothing to change them (and nothing in the works yet).
Where do we demonstrate so women are also given this opportunity to change, same as the men?
Will the ACLU take on this case of equal opportunities for women, and make a case for a change we can all believe in?
"The European Union banned atrazine in 2004." That should be a clue. This is one more reason to buy organic goods whenever possible. We are not aware of all the effects of massive use of herbicides, pesticides etc., but there are clear alarms.
Joe
A huge mahalo from Maui to all you dedicated CDers for injecting a bit of needed levity into an otherwise horrifying topic. Things have become so bad "out there" that I even dread reading CD. Again, thanx!
Obviously, the most prudent thing to do would be to ban the chemical in the US as well. Equally obviously, the government is not interested in the well being of the citizenry to do that.
You know, rich people are not immune to those effects. Nor are any shareholders of Syngenta AG.
What comes to mind is the watershed of the Mississippi river, and others. Every pesticide and chemical fertilizer used by farmers and gardeners west of the appalachians, and east of the rockies eventually goes into the Mississippi delta and creating massive 'dead zones' offshore.
Someone mentioned to me the other day, it's not the plants we feed when we apply chemicals, it's the billions of microbes living in our soils, that in turn feed the plants. These pesticides are not only killing the harmful bacteria, nematodes, etc., etc., but the necessary ones as well. Bio-diversity is what makes this world go round, pesticides, chemical fertilizers, and monocultures will surely destroy it.