5.6 MYTH:

Roundup is a benign and biodegradable herbicide


Roundup persists in the environment and has toxic effects on wildlife

Manufacturers claim that Roundup, the glyphosate-based herbicide used on most GM crops, breaks down quickly and harmlessly in the environment. But research shows that this is untrue:

  • In soil, glyphosate has a half-life (the length of time taken to lose half its biological activity) of between 3 and 215 days, depending on soil conditions.85,86 In water, glyphosate’s half-life is 35–63 days.87
  • Although glyphosate binds well to soil particles, the Danish National Pesticide Monitoring Program showed that glyphosate and its main breakdown product AMPA are washed out of the root zone of clay soils in concentrations that exceed the acceptable quantities for drinking water (0.1 µg/l), with maximum values of over 5 µg/l.88
  • Glyphosate was detected in between 60 and 100% of air and rain samples taken in the American Midwest during the crop growing season in the American Midwest, where Roundup Ready GM crops are widely planted.89
  • Glyphosate and its main breakdown product, AMPA, were detected in streams in the American Midwest during the crop growing season.90
  • Glyphosate is toxic to earthworms91 and reduces bird populations due to habitat changes.92
  • Roundup is highly toxic to amphibians. A study in a natural setting found that Roundup application at the rate recommended by the manufacturer eliminated two species of tadpoles and nearly exterminated a third species, resulting in a 70% decline in the species richness of tadpoles. Contrary to common belief, the presence of soil does not reduce the chemical’s effects.93 Further experiments with lower concentrations, well within levels to be expected in the environment, still caused 40% amphibian mortality.94
  • Claims that Roundup and glyphosate are safe for human health and the environment have been overturned in courts in the United States95 and France. The French court forced Monsanto to withdraw advertising claims that Roundup is biodegradable and leaves the soil clean after use.96

Regulatory bodies around the world have not caught up with the state of the science on Roundup and glyphosate. Instead they continue to rely on decades-old studies, mostly sponsored by manufacturers, to claim it is safe. An objective up-to-date review of Roundup and glyphosate’s persistence and toxicity is long overdue.

  • For references, please click here.
  • Download a PDF of the full GMO Myths and Truths report
  • We work hard to bring you reports backed up by strong science.
    Please help us by supporting our work.
    Donate button


0 #2 sam 2014-04-08 06:38
The comment above sounds like a corporate defender to me... Monsantos got all the money in the world to clear any bad about its name.

This stuff does stay. Do any test and you will see.
0 #1 Swiss Frank 2013-05-26 04:10
I'm not a reflexive corporate defender. Tell me Roundup is not safe, and I'll hear you out. I'll also ask where all the body bags are. Show me the tumors. As the article states, Roundup is omnipresent across the entire US midwest, so PRECISELY thx to its ubiquity we should have no trouble seeing its bad effects compared to other regions that don't use it at all. I'm positive that, were there any suspected health effects whatsoever, they'd be mentioned in this type of "article." I guess there actually aren't any.

I'm hugely in favor of clean air and clean water and left an otherwise great job partly because I couldn't stand the pollution. I loved the frogs around my old apartment and when they came out on the sidewalk after a heavy rain took care not to squish any with my bicycle or the building's automatic doors. But in a pond with farm run-off, 70% of tadpoles dying doesn't upset me that much. 99% of tadpoles die of something. I'd be a bit more concerned about a precipitous drop in adult frog population, or concentrations in apex predators that eat tadpoles. I also am ABSOLUTELY POSITIVE an article such as the one you cited would scream to the rafters if these species were anything less than "least concern" on the endangered species scale; the fact that there's no mention tells me this kind of frog's not disappearing. I do note that amphibians perform valuable roles in the local biosphere. However I also note that the local biosphere seems to belong to a farmer, who we have to credit with understanding his land, and if he's willing to lose the frogs in order to lose the weeds, then apparently the value of the frogs isn't as high as the value of weedless crops.

I take special exception to the last point, which I quote: "Claims that Roundup and glyphosate are safe for human health and the environment have been overturned in courts in the United States and France." I'm happy to believe it. However, claims being overturned doesn't tell us much about whether the claims are true or not. Roundup may really BE "safer than salt"--I don't pretend to know-- but if there's laws against saying so, such claims are overturned. We see every day truthful speech that is squashed* and lies that are protected**.

(* eg Larry Summers losing his job as president of Harvard in part for summarizing fairly accurately one widely-held view of science's understanding of the difference between the sexes. Or a different type of case: Bradley Manning's wikileaks.)

Add comment

Security code