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A new study published in the January issue of International Journal of Toxicology titled, "Glyphosate Commercial Formulation Causes Cytotoxicity, Oxidative Effects, and Apoptosis on Human Cells: Differences With its Active Ingredient," raises renewed concern that formulations of the world's most popular herbicide glyphosate (e.g. Roundup), used primarily in the production of GM food, represent a serious human health threat.
Researchers studied the effects of a glyphosate-based formulation on human cells, at dilutions far below agricultural applications. The researchers discovered that while glyphosate and its amino acid metabolite, aminomethylphosphonic acid (AMPA), showed little to no observable toxic effects in isolation, a glyphosate-based formulation containing adjuvants produced a variety of adverse effects on cellular oxidative balance, including the following signs of oxidative stress:
- Increases in reactive oxygen species
- Increases in nitrotyrosine formation
- Increases in superoxide dismutase activity
- Increases in glutathione levels
The glyphosate formulation studied also triggered two 'death proteins' in human cells known as caspase 3/7, inducing pathways that activate programmed cell death (apoptosis), a clear sign of significant toxicity.
Most importantly, the researchers concluded: "These results confirm that G [glyphosate] formulations have adjuvants working together with the active ingredient and causing toxic effects that are not seen with acid glyphosate."
This study reveals an important biosafety issue when it comes to the widespread use of glyphosate-based agrichemicals in our food and environment, namely, an ingredient like glyphosate may not reveal its inherent toxicity in isolation, and that toxicological risk assessments performed on these chemicals do not take into account the reality of synergistic toxicity, i.e. the total adverse effects often far exceed the sum of the individual components being evaluated.
We addressed this issue previously in our article "Research: Roundup Herbicide Toxicity Vastly Underestimated," where we reported on a 2012 study published in the journal Archives of Toxicology that revealed the glyphosate formulation known as Roundup is toxic to human DNA in dilutions 450-fold lower than used in agricultural applications.[i] This finding could not be anticipated from the known toxicological effects of glyphosate alone. The likely explanation is that the surfactant polyoxyethyleneamine within Roundup dramatically enhances the absorption of glyphosate into exposed human cells and tissue.
Another related study, published in the journal Toxicology in 2011, titled, "Ethoxylated adjuvants of glyphosate-based herbicides are active principles of human cell toxicity," found 24 hour exposures on liver, embryonic and placental cell lines at concentrations as low as 1 ppm – a dose well within "acceptable" environmental and occupational doses – resulted in negative effects on cellular respiration and membrane integrity.[ii]
The authors struck to the heart of the issue by concluding: