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Much of the focus of late has been on the toxicity of the main ingredient in Roundup 'weedkiller,' namely, glyphosate. And rightly so: far from being 'practically non-toxic,' as advertising copy once bragged,[i] the chemical has recently been shown to exhibit toxicity in the parts-per-trillion concentration range, and is being found literally everywhere: in the water, soil, air, rain and our food. But very little research has been performed on its metabolites and so-called 'inactive ingredients' – until now.
A new study, published in Pesticide Biochemistry and Physiology titled, "The effect of metabolites and impurities of glyphosate on human erythrocytes (in vitro)," reveals that the problem with the growing global contamination of the biosphere with agrichemicals used in the farming of genetically modified foods is far worse than most will either admit or acknowledge.
The researchers describe the background context of their study:
"Today, the dissemination of glyphosate in the environment increases, and humans are permanently exposed to its action. Worstcase scenario provides even ten-fold increase of using a glyphosate in the following years . Considering the widespread and frequent use of glyphosate throughout in world, thus the current risk assessment is important because the exposure will concern not only the users of the preparations containing glyphosate, but also those who do not have direct contact with that herbicide."
The researchers used human red blood cells (erythrocytes) to evaluate the effects of "glyphosate, its metabolites: aminomethylphosphonic acid (AMPA); methylphosphonic acid and its impurities: N-(phosphonomethyl)iminodiacetic acid (PMIDA), N-methylglyphosate, hydroxymethylphosphonic acid and bis-(phosphonomethyl)amine," looking specifically at the following indications of damage:
- Hemolysis (the rupturing of red blood cells)
- Hemoglobin oxidation (oxygen-induced damage to the central metalloprotein within red blood cells)
- Levels of reactive oxygen species (ROS) formation (an indication of oxygen-induced damage)
- Changes in shape of red blood cells
The red blood cells were exposed to different concentrations of glyphosate and its metabolites and impurities at concentration ranges between .01-5 millimolar (mM) for 1, 4 and 24 hours. The authors explain that their choice of ranges "are within the range of the concentrations that are present in the blood of persons not exposed (.01 mM) or may enter human organism only as a result of acute poisoning (0.05–5 mM)." In other words, simply breathing the air, drinking the water, and eating the food in our post-industrial world results in measurable blood levels of .01 mM (i.e. 1.69 parts per million (ppm) or 1.69 mg/L) in the general population.
To put these ranges into further perspective, the US EPA has recently proposed to hike the allowed residue limits of glyphosate in food and feed crops to 100 ppm in teff animal feed and 40 ppm in oilseed crops, essentially telling the American public, "Let Them Eat Roundup Ready Cake."
Also, those working with glyphosate, eating glyphosate-sprayed food, or close to agricultural regions where it is heavily applied, would have far higher levels than .01 mM in their blood. The concentrations, in fact, can accumulate to deadly levels, as evidenced by a recent report proposing that the chemical may be responsible for causing a mysterious global epidemic of deadly kidney disease in farming regions around the world.
The authors also explained their choice of red blood cells for toxicological evaluation: "Damage to erythrocytes is widely used as indicator of toxicity of numerous xenobiotics ,  and . Pesticides, drugs and other toxic compounds are transported by blood of living organisms, thus they enter red blood cells."
The results, which the researchers curiously describe as "negligible," were reported as follows: