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Nature and Environment

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Experts Declare Glyphosate Herbicide (Roundup) a 'Probable Carcinogen'

Glyphosate Herbicide

Big news about Monsanto’s Roundup, the herbicide use­­d on many genetically modified crops:  17 experts from 11 countries in the Monograph Working Group of the International Agency for Research on Cancer have determined that glyphosate should be classified as a “probable human carcinogen.” This decision comes over 30 years after Monsanto began marketing glyphosate as Roundup and assuring the public it was perfectly safe.  Use of Roundup on our food has increased with the adoption of genetically modified crops, and Monsanto has succeeded in convincing the EPA to increase the residue levels legally allowed on our food.  Here’s what the experts had to say in the announcement in the medical journal Lancet Oncology:

“Glyphosate is a broad-spectrum herbicide, currently with the highest production volumes of all herbicides. It is used in more than 750 different products for agriculture, forestry, urban, and home applications. Its use has increased sharply with the development of genetically modified glyphosate-resistant crop varieties. Glyphosate has been detected in air during spraying, in water, and in food. There was limited evidence in humans for the carcinogenicity of glyphosate. Case-control studies of occupational exposure in the USA, Canada, and Sweden reported increased risks for non-Hodgkin lymphoma that persisted after adjustment for other pesticides. The AHS cohort did not show a significantly increased risk of non-Hodgkin lymphoma. In male CD-1 mice, glyphosate induced a positive trend in the incidence of a rare tumour, renal tubule carcinoma. A second study reported a positive trend for haemangiosarcoma in male mice. Glyphosate increased pancreatic islet-cell adenoma in male rats in two studies. A glyphosate formulation promoted skin tumours in an initiation-promotion study in mice.

Glyphosate has been detected in the blood and urine of agricultural workers, indicating absorption. Soil microbes degrade glyphosate to aminomethylphosphoric acid (AMPA). Blood AMPA detection after poisonings suggests intestinal microbial metabolism in humans. Glyphosate and glyphosate formulations induced DNA and chromosomal damage in mammals, and in human and animal cells in vitro. One study reported increases in blood markers of chromosomal damage (micronuclei) in residents of several communities after spraying of glyphosate formulations. Bacterial mutagenesis tests were negative. Glyphosate, glyphosate formulations, and AMPA induced oxidative stress in rodents and in vitro. The Working Group classified glyphosate as “probably carcinogenic to humans” (Group 2A).”

You can read the entire article for free by registering with The Lancet Oncology.

Photo by Fotolia/Justinb: The herbicide glyphosate doubled in use from 85-90 million pounds in 2001 to 180-185 million pounds in 2007, according to the Environmental Protection Agency (EPA).


Cheryl Long is the editor in chief of MOTHER EARTH NEWS magazine, and a leading advocate for more sustainable lifestyles. She leads a team of editors which produces high quality content that has resulted in MOTHER EARTH NEWS being rated as one of North America’s favorite magazines. Long lives on an 8-acre homestead near Topeka, Kan., powered in part by solar panels, where she manages a large organic garden and a small flock of heritage chickens. Prior to taking the helm at MOTHER EARTH NEWS, she was an editor at Organic Gardening magazine for 10 years. Connect with her on .