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Monsanto's Roundup More Deadly to Liver Cells than Glyphosate Alone

Gasniera C, C Dumontb, N Benachoura, E Claira, MC Chagnonb and GE Séralini. 2009. Glyphosate-based herbicides are toxic and endocrine disruptors in human cell lines. Toxicology doi:10.1016/j.tox.2009.06.006.

Synopsis by Negin P. Martin, Ph. D

Very low doses of some types of the herbicide Roundup can disrupt human liver cell function; the formulations' toxicity may be tied to their "inactive" ingredients rather than the active weed-killing ingredient glyphosate.

French scientists report that a number of Roundup formulations tested at very dilute concentrations can alter hormone actions and cause human liver cells to die within 24 hours of treatment.

The toxicity of some of the formulations was independent of how much glyphosate - the active herbicide in Roundup - they contained, suggesting it is other "inert" ingredients that may alone - or in combination with each other and/or the weedkiller - assault the cells. This study's results are similar to prior studies - as reported in a recent Environmental Health News article - that find human embryo cells are affected more by the Roundup formulations and an inert ingredient than by the active ingredient.

The levels of Roundup used in this study are similar to what is typically found in food crops or animal feed treated with Roundup. Because of this, it is possible that people, livestock and wildlife may be exposed to levels of the herbicide mix that can damage cells.

Glyphosate is harmful to humans and animals even at a very low dose. It is often tested by itself in regulatory studies to determine if the Roundup formulation is toxic.

However, according to this study, levels of glyphosate in Roundup formulations are not good indicators of toxicity.

The ingredients responsible for the increased potency of Roundup formulations seen in this study - as compared to purified glyphosate - remain unknown. The chemical formulas of herbicide additives are generally protected as trade secrets, and the researchers did not try to chemically identify them. Therefore, their effects cannot be easily investigated and they remain undetected in the environment.

Roundup was developed as a weapon against weeds. Many genetically modified (GM) plants have been developed to tolerate Roundup. Today, Roundup is the most widely used weedkiller in the world and 75 percent of all GM plants are engineered to resist the herbicide. Monsanto agricultural company produces both Roundup and Roundup-resistant GM plants.

Four Roundup formulations - Roundup Express 7.2 (R7.2), Bioforce (R360), Grands Travaux (R400) and Grands Travaux Plus (R450) - were tested in this study. All formulations were more potent than purified glyphosate (at similar levels to R360) in causing cell death. Surprisingly, R400 containing less glyphosate was more toxic to human liver cells than R450.

In the study, exposure of a single gene regulated by either estrogen or androgen hormones demonstrated that all formulations disrupt hormone function more efficiently than purified glyphosate. The findings show that the formulations act against the hormones to produce anti-estrogenic and anti-androgenic effects.