Glyphosate-Based Herbicide Study Shows Multiple Ingredients are Toxic

​Scientists studying the toxic effects of glyphosate, 14 herbicides (including Roundup) that contain glyphosate, and several other chemicals (called “formulants” or “adjuvants”) also present in herbicides, have produced compelling evidence that glyphosate formulations are more toxic than glyphosate in isolation. Their findings lead to an unavoidable conclusion: regulatory agencies, which have approved glyphosate-based herbicides (GBH) primarily based on studies of glyphosate alone, have not properly scrutinized glyphosate formulations as they are used by consumers.

Glyphosate is Only One Ingredient Among Many in Herbicides Like Roundup

The researchers, Professor Gilles-Eric Séralini from the University of Caen Normandy, France, and his colleagues, Dr. Nicolas Defarge and Dr. Joël Spiroux, first tested glyphosate alone, on both plants and human cells, diluted to percentages that are recommended for agricultural use. They report, “No observable adverse effect was measured.”

In a second test, tomato plants were watered and sprayed for 7 days under the following exposure conditions:

• Water only (control)
• Glyphosate alone
• POEA, polyethoxylated tallowamine, a surfactant. Surfactants are additional ingredients that help the herbicide cling to the leaf and increase herbicide leaf penetration.
• Glycophan, a GBH, tested at recommended agricultural dilutions (RAD)
• Roundup GT, a GBH, tested at RAD
• Roundup Weathermax, a GBH, tested at RAD

Photos of the plants, which can be seen online on page 4 of the study, tell the story. Seralini and his team found that most of the toxic effects occurred during the first 5 days. Over the first 5 days, glyphosate alone “did not show any herbicidal activity.” The three GBH formulations, however, all showed clear toxic effects. As the photos suggest, the formulant POEA was highly herbicidal within three days of exposure.

“After 7 days, G [glyphosate] alone began to desiccate and to whiten a few upper leaves, only starting to demonstrate minor herbicidal effects, while plants had already been killed by all the other treatments except water (control C).”

Testing on human embryonic kidney cells produced similar results. The cells were killed by GBH formulations within 90 minutes, while glyphosate alone did not demonstrate similar toxicity. The authors report that the GBH formulations were thousands of times more toxic to the cells than glyphosate alone.

POEA demonstrated the same toxicity as the glyphosate-based herbicides. In fact, the researchers stated that the POEA formulant was 3,450 times more toxic than glyphosate alone. They believe that POEA may be “the real principal of toxicity” in the herbicide formulations that contain it.

The researchers also studied very low levels of exposure to the glyphosate formulations, formulants, and glyphosate alone. Even at levels that were not obviously toxic to the cells, all of the exposures produced endocrine disruption.

The study produced one other surprising finding: researchers found the heavy metals arsenic, chromium, cobalt, lead and nickel – all known to be toxic and endocrine disruptors – in 22 pesticides, including 11 glyphosate-based pesticides. (Herbicides are included in the pesticide category.)

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The results of this testing, according to Seralini and his colleagues, indicate that glyphosate may be the least toxic substance in most glyphosate-based herbicides. This raises a serious problem, because it is testing on glyphosate that is used by regulatory agencies to determine acceptable levels of exposure GBH formulations such as Roundup. Surfactants and other formulants, if they are known (manufacturers are not required to identify the inert ingredients in their pesticides) are not tested for long-term health effects.