December 20, 2012

Testes Hit By Herbicides

  • A pesticide is shown to cripple the male gonads of more than 100 species.
  • Certain frogs appear to suffer the most dire effects as the chemical made males turn into females.

Male African clawed frogs — beware. Studies show the pesticide atrazine turned the male frogs into females.

A review of 142 studies on the effects of the herbicide atrazine had bad news for testes.

“Essentially, atrazine chemically castrates animals. When you look at a male exposed to atrazine, the testes are missing sperm,” Tyrone Hayes of the University of California, Berkeley told Discovery News.

The effects of atrazine on male development are consistent across all examined animals, found a study published by a team of 22 researchers from more than 60 nations in the Journal of Steroid Biochemistry and Molecular Biology.

Mammals, reptiles, and fish were all affected, but amphibians caught the worst of it. In a study by Hayes, male African clawed frogs turned into females after exposure to atrazine, which kills weeds around the world in everything from corn fields to orchards.

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“And this is not at extremely high concentrations” said co-author of the review Val Beasley of the University of Illinois in a press release. “These are at concentrations that are found in the environment.”

Humans aren’t spared the effects of atrazine, the world’s second most common herbicide after glyphosate, Hayes said.

Hayes pointed to studies correlating atrazine exposure tolow sperm quality, birth defects, miscarriage, and breast cancer

“The hotspot is probably the US, because we use so much” Hayes said. “The biggest hotspot in the US is the Midwest, the cornbelt, another is Florida where it is used on sugar cane.”

But, he added, “We’re all exposed to it. Surface water, rainwater you name it atrazine is in it.”

The European Union has already banned the use of atrazine

“I think a global ban is certainly in order” Hayes said.

The maker of atrazine, Switzerland-based Syngenta, disagrees

“The science is clear. Atrazine cannot, does not, and will not cause adverse effects at levels to which people would ever be exposed in the real world” Ann Bryan, Syngenta’s senior manager of external communications told Discovery News.

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“Independent organizations such as the EPA, World Health Organization , Australian Pesticides and Veterinary Medicines Authority , and others have conducted or reviewed studies that consistently support the safety of atrazine” Bryan said.

Syngenta and Hayes haven’t always been at odds.

Hayes was introduced to atrazine when he worked on the chemical for Syngenta, he said. Now, though, Hayes says his public talks have been disrupted by Syngenta, and he’s received vulgar and threatening comments from them.

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“There is no truth to these claims” said Syngenta’s Bryan.

No matter what side of the atrazine debate wins, there will be economic consequences.

In the face of a global atrazine ban… “We [Syngenta] would be concerned for the millions of farmers and the US consumers who benefit from atrazine. US consumers benefit by $3.6 to $4.4 billion annually due to decreased producer costs” Bryan said.

Banning the chemical in just some areas might not be a good idea

“There needs to be a system of global [agricultural chemical] regulation” review co-author Val Beasley told Discovery News.

“What we don’t want to see is a situation like DDT” said Beasley.

After being banned in the US, DDT continued to be used in the developing world to eliminate insects.

 

Source: http://news.discovery.com/earth/pesticides-testes-males-111202.html

Widely Used Weed-Killer Causes Reproductive Harm to Animals and People

A recent scientific review and new study add to the mounting evidence that the chemical atrazine is harming animals and people far from the farms where the herbicide is used.

  • A review in the Journal of Steroid Biochemistry and Molecular Biology describes a litany reproductive damages to amphibians, fish, reptiles and mammals caused by the chemical herbicide atrazine.
  • A new study published in Environmental Research links atrazine to menstrual cycle disruptions in people in Illinois and Vermont, where drinking water is contaminated at levels previously considered safe.

Atrazine Contaminates Water Supplies in Farm Communities
Atrazine is the second-most widely used herbicide in the United States, at 75 million pounds of it applied annually to fields of corn and other crops, and is used in 60 other countries around the world. The chemical, long suspected in the decline of frog populations, is routinely found in groundwater and surface water – rivers lakes and streams – as well as rain.

A 2010 study by the Natural Resources Defense Council found atrazine in 80 percent of public water systems of the 153 sampled in the Midwest and Gulf States, where the Mississippi River carries agriculture pollution from the plains. The U.S. Geological Survey found atrazine in 75 percent of the stream water and 40 percent of the groundwater sampled in the same regions.

EPA Waiting for “Smoking Gun” Before Considering Ban?
Among the reproductive problems described in the new review in Journal of Steroid Biochemistry and Molecular Biology are the following:

  • changes to the expression of genes involved in hormone signaling;
  • interference with metamorphosis;
  • inhibition of key enzymes that control estrogen and androgen production;
  • and skewing of the sex ratio of wild and laboratory animals (toward female).

And just recently, a study in Envionmental Research linked drinking atrazine-contaminated tap water to menstrual disorders in women in Illinois and Vermont, even when the tap water in question had far less than the Environmental Protection Agency allowable level of 3 parts per billion. The manufacturer of the weed-killer argues that perhaps these women were just under stress, but this study is not the first to tie atrazine in drinking water to health issues in people. In 2009 a different study tied atrazine in drinking water to low birth weight in Indiana newborns.

Several years ago, NRDC and others began calling for a complete phase-out of atrazine use and at least one of the scientists involved in the study echoes the call for a ban:

“I hope this will stimulate policymakers to look at the totality of the data and ask very broad questions,” Tyrone Hayes, a professor of integrative biology at the University of California at Berkeley and lead author of the review, told Science Daily. “Do we want this stuff in our environment? Do we want — knowing what we know — our children to drink this stuff? I would think the answer would be no.”

Unfortunately, Tom Philipott of Mother Jones reports that EPA will “not even consider” a ban before 2013, which doesn’t mean they will ban it in 2013, but that they will think about it then.

What Can You Do to Protect Yourself from Atrazine?
If you live in a farming region, you can get involved in local and state efforts to reduce or eliminate atrazine without waiting for new federal regulations or a ban. You can request the water quality report from your local utility and urge your utility to step up monitoring of for atrazine to document the problem and then alert the public to the dangers. And, especially farming communities where atrazine has been found, you should to install and use home water filtration systems.

Source: http://www.care2.com/causes/widely-used-weed-killer-causes-reproductive-disorders-in-animals-and-people.html