TORONTO — The French scientist who led the study questioning the safety of Roundup herbicide and genetically modified corn is adding new fuel to the debate.
Gilles-Eric Séralini released a copy of his new paper examining the adjuvants used in Roundup formulations to the Western Producer after he spoke in Toronto Feb. 16 at the annual Canadian Organic Conference.
A source with the publisher has confirmed that the paper has been published.
“There are several hidden toxic compounds in Roundup that are far, far more toxic than glyphosate, but they have not been tested in long-term studies like glyphosate — that means for two years with a rat,” Séralini said.
The paper, called Ethoxylated adjuvants of glyphosate-based herbicides are active principles in human cell toxicity and published in Toxicology magazine, compares the toxicology and composition of nine Roundup formulations using different human cell lines.
The study shows that glyphosate-based herbicides pose an environmental and occupational risk for humans, including for farmers and others who spray the products.
As in his earlier paper, Séralini recommended that longer-term studies be used to measure the potential toxic effects of the entire formulations rather than just the glyphosate content.
“I don’t think that agricultural workers understand that glyphosate is not Roundup,” Séralini said.
“Roundup is 100,000 times more toxic on human cells than glyphosate, and glyphosate is just 15 percent of what’s in Roundup.… There’s a vast underestimation of its effects.”
Responding to Séralini’s claims, a Monsanto spokesperson said glyphosate has an excellent human health record and a history of safe use in more than 130 countries.
“This is confirmed by the extensive studies as well by the first-hand experience of millions of farmers,” said Thomas Helscher, Monsanto director of corporate affairs.
However, glyphosate isn’t the only chemical in Roundup.
“Surfactants are routinely added to herbicide formulations to break down the waxy coating on plants and allow for efficient absorption,” Helscher said.
“The complete formulation information is provided to the regulatory agencies and regulatory submissions include data on the surfactants used.”
Bob Hartzler, an Iowa State University weed science professor, said surfactants are an essential component of glyphosate formulations.
“It (glyphosate) is inefficient at moving from the leaf surface into the plant, so they have to add additional products,” he said.
Without surfactants, he added, glyphosate would bead up on the plant’s leaves, much like water droplets on a freshly waxed car.
“The surfactants allow the glyphosate to penetrate into that wax. It facilitates diffusion into the leaf.”
However, Hartzler said the problem with surfactants is they are toxic for frogs and other amphibians.
“It’s well documented that formulations of glyphosate, whether it’s Roundup or Touchdown or any other generic … are extremely toxic to amphibians. That is due to that surfactant. The amphibians have a very wet skin that absorb things very easily.”
Commenting on the findings of Séralini’s study that Roundup is substantially more toxic than glyphosate, Hartzler said he’s not a toxicologist but some formulations of glyphosate do come with a warning label.
“A lot of times that (warning) is due to the risk associated with getting it on your eyes. The surfactants, they’re designed to penetrate… and can be pretty toxic to the eyes.”
Helscher said existing research doesn’t back Séralini’s comment that Roundup is 100,000 times more toxic than glyphosate.
“We haven’t seen data to support such a statement,” he said.
“Extensive animal data and human experience contradicts findings of Petri dish experiments … with glyphosate-surfactant herbicides.”