|Glyphosate is marketed as Roundup. Photo Creative Commons|
This reputation for safety is based on facts. In the environment, measurements have shown that glyphosate quickly disappears: it can be degraded by soil microbes and sunlight, washed away, or immobilised in the soil. In animals, it has low toxicity because animals don't have the metabolic pathway that glyphosate interferes with in plants, and the herbicide rapidly passes unchanged through the body to be excreted harmlessly in urine. All true, and all based on science.
However, there's another side to these facts.
Besides annihilating (non-GM) plants with super-efficiency, glyphosate has a second very powerful property: it sticks to positively charged materials in its surroundings. Such materials include:
- soil particles
- metals such as calcium, magnesium, strontium and iron (all found in 'hard' water)
- cadmium and other heavy metals (all of which are toxic to the kidney)
- arsenic (an agri-chemical contaminant and also harmful to the kidney).
Chemical glyphosate is so good at grabbing such minerals it has been used as a de-scaler in pipes and boilers.
The problem this presents is that, whereas free glyphosate and its major break-down product, 'AMPA' can be measured easily, once they attach themselves to other materials they are so tricky to detect that they become effectively invisible.
When it's bound to minerals glyphosate no longer kills plants. Agriculture experts in hard-water areas know they must add ammonia to their herbicide mix to release the herbicide from the metal complexes.
The story of glyphosate is further complicated by the more recent discovery that more than one glyphosate molecule can stick to a metal particle. This makes the whole much bigger. Also, it seems the configuration of the resulting complexes can take several forms.
A question which has never been explored until very recently is whether glyphosate-plus-metal could be harmful.
Beneath the surface of the world's safest ever herbicide, with its easily detectable chemical glyphosate and inert passage through our bodies, there may lurk another version of the herbicide which isn't so benign and is hidden from view.
Many scientists, public health officials, and the World Health Organisation have been struggling to explain pockets of abrupt kidney failure in areas of Sri Lanka, India and several Central American countries. The syndrome, referred to as 'Chronic Kidney Disease of unknown aetiology', or CKDu, has emerged in the last two decades and is appearing in progressively younger members of the populations. Many victims are unaware of being ill until the end stage is reached.
Studies of the diseased kidneys and associated biochemistry in CKDu suggest exposure to a toxin, although the usual liver responses are absent. These, plus the geographical and socio-economic patterns, suggest environmental and occupational links. Beyond that, no single, common, toxic material can be identified, and the inescapable conclusion is that CKDu is a multi-factorial disease making its causes extremely difficult to unravel.
The timing and locations of CKDu emergence have coincided with expanding use of glyphosate and the herbicide has been shown to cause renal dysfunction in rats, but the herbicide does not cause kidney failure. Similarly, CKDu is associated with agricultural areas with high levels of pesticide use, but pesticides don't cause kidney failure. CKDu is associated with hard-water areas, but hard water does not cause kidney failure. Dehydration is a risk factor for CKDu, but dehydration does not cause kidney failure. Arsenic is a contaminant of many agri-chemicals and features in the bodies of CKDu sufferers, but it's also present in lots of healthy people.
However, noting that glyphosate interacts with the elements which make hard water 'hard', a team of Sri Lankan scientists has proposed a disturbing role for glyphosate in CKDu which could tick all the boxes.
The researchers suggest that glyphosate's habit of forming large complexes with toxic metals and arsenic can smuggle these past the body's natural defences which should channel harmful substances to the liver to be made safe. This could happen, for example, because glyphosate has a region chemically similar to the substance normally used by the body to ferry toxic metals to the liver.
Inevitably the glyphosate-metal complex will end up in the kidneys where it will enter a tubule which secretes ammonia. At this point, the complex will break apart and the toxic metal will be released back into the body.
Cumulative heavy metal toxins in the body and cumulative renal damage finally lead to kidney failure.
Such a problem will be exacerbated when the urine becomes more concentrated due to dehydration.
People in agricultural areas with hard-water could be absorbing glyphosate-metal complexes from glyphosate-contaminated drinking water, or from glyphosate agricultural sprays made up with local water, or from food contaminated by both sources.
The proposal deserves urgent further study. We need to know what happens to the glyphosate-metal complexes in our digestive tract and after dermal or respiratory exposure.
Another question is whether glyphosate applied as Roundup (which has extra ingredients to aid cell penetration) is catastrophically exacerbating the harmful effects of such glyphosate complexes .
It seems Roundup Ready GM crops may come with a very heavy humanitarian price tag.
The kidney problems we're noticing because they are causing acute organ failure and death in high-risk areas, could well be eating away, insidiously, at the health of people everywhere else.
The Sri Lankan scientists may not have got it all right, but even if part of what they've proposed is accurate, it must be investigated.
Don't let this idea be swept under the carpet: demand a full scientific and independent investigation.
 ROUNDUP IS NOT SAFE TO EAT - March 2013
- Channa Jayasumana, et al., 2014, Glyposate, Hard Water and Nephrotoxic Metals: Are Tehy the Culprits Behind the Epidemic of Chronic Kidney Desease of Unknown Etiology in Sri Lanka?, Journal of Environmental Research and Public Health, 11
- Melissa S. Caetano, et al., Understanding the Inactivation Process of Organophosphorus Herbicides: A DFT Study of Glyphosate Metallic Complexes with Zn2+, Ca2+, Mg2+, Cu2+, Co3+, Fe3+, C3+, and Al3+. International Journal of Quantum Chemistry 112
- Dr Eva Sirinathsinghji, Sri Lanka Partially Bans Glyphosate for Deadly Kidney Disease Epidemic, Institute of Science in Society Report, 9.04.14