Disturbing new research published in the Journal of Applied Toxicology indicates that genetically modified (GM) crops with "stacked traits" - that is, with multiple traits such as glyphosate-herbicide resistance and Bacillus thuringiensis (Bt) insecticidal toxins engineered together into the same plant, are likely to be far more dangerous to human health than previously believed, and all of this is due to their synergistic toxicity.
The natural resistance that most plants have to the chemical glyphosate, the active ingredient in the herbicide Roundup, has been engineered into many GM plants, so that fields can be sprayed indiscriminately with herbicide without the plants having to worry about destroying the crops. While the GM glyphosate-resistant plants survive, they subsequently contain residues of glyphosate and its various metabolites (e.g. aminomethylphosphonic acid) that present a significant health threat to the public.
In this latest study the glyphosate-containing herbicide Roundup was tested on human embryonic kidney cells at concentrations between 1 to 20,000 parts per million (ppm). It was found that concentrations as low as 50 ppm per million, which the authors noted were "far below agricultural dilutions," induced cell death, with the 50% of the cells dying at 57.5 ppm.
The researchers also found that the insecticidal toxin produced by GM plants known as Cry1Ab was capable of causing cell death at 100 ppm concentrations.
Taken together the authors concluded
"In these results, we argue that modified Bt toxins are not inert on nontarget human cells, and that they can present combined side-effects with other residues of pesticides specific to GM plants."
These disturbing findings follow on the heels of other recent revelations that have discovered that Roundup is toxic by several orders of magnitude more than previously believed. Only 5 days ago (Feb. 14, 2012) the journal Archives of Toxicology reported that Roundup is toxic to human DNA even when diluted to concentrations 450-fold lower than used in agricultural applications. This effect is likely due to the presence of the surfactant polyoxyethyleneamine within the Roundup formulation which may dramatically enhance the absorption of glyphosate exposure into exposed human cells and tissue.