A hard look at glyphosate

Most GM crops are designed to survive repeated spraying with glyphosate.

In January 2017 new research linked roundup (the most commonly used formulation of glyphosate) with non-alcoholic fatty liver disease. In March 2015, the World Health Organisation (WHO)'s International Agency for Research on Cancer (IARC) classified glyphosate as a probable human carcinogen.

Glyphosate, marketed by Monsanto as Roundup, is the world’s best selling weedkiller and the basis for GM herbicide tolerant crops, which can absorb high levels of the herbicide without being killed. GM companies promised it would cut costs and work for farmers. How glyphosate works in plants and soil.

The truth emerging is that this is not the case. 

Proponents of GM crops often claim that they have reduced pesticide use. In fact, glyphosate use has increased fifteen-fold since herbicide tolerant GM crops were introduced.

Glyphosate is widely said to be “safe” for the environment and humans, including the residues it leaves in food, feed and soil. 

In June 2013 GM Freeze and Friends of the Earth released the results of testing of 182 city-dwelling volunteers from 18 European countries. None of the volunteers had handled or used glyphosate products in the run up to the tests. The results showed that on average 44 per cent of samples contained traces of glyphosate. Of the ten samples taken in the UK, seven had weedkiller traces.

This is the first time monitoring has been carried out across Europe for the presence of the weedkiller in humans, and GM Freeze is demanding more thorough scientific evaluation of these results to determine how risky this exposure is and where it is coming from. We also want better testing of glyphosate residues in food, as minimum residue limits appear to be breached often, but routine testing is not done to protect consumers.

The risks posed by glyphosate are well documented. In a comprehensive report published in June 2011, GM Freeze and Greenpeace examines some of the many problems becoming clear including:

- Glyphosate exposure is associated with cancer, birth defects and neurological illnesses (including Parkinson’s disease), and it may be a ‘gender-bender’ that interferes with human hormone balances and function. Research shows that glyphosate can cause damage to cells, including human embryo cells. A 2012 study revealed higher cancer and death rates for rats fed GM maize and Roundup.

- Environmental impacts of glyphosate include damage to rivers and on the animals living in them, disruption of soil nutrients and contamination of drinking water. Of increasing concern is the spread of “super weeds” that aren’t killed either and are forcing farmers to resort to hand weeding vast fields at considerable cost and effort – exactly the opposite of GM’s promise [watch Farmer to Farmer: The truth about GM crops). There are now over 20 weed species resistant to glyphosate affecting over 100 resistant strains on some 6 million hectares of otherwise good farmland in Argentina, Brazil and the US. Monsanto recommends using even higher levels of even more toxic chemicals, including some that had been discontinued as too dangerous, to control superweeds. It's a war we can't win.

In late 2010 the European Commission postponed for three years a badly needed safety review of glyphosate and 38 other agrochemicals. GM Freeze believes the scientific evidence is so strong that a fully independent review should be conducted immediately and no GM glyphosate tolerant crops should be authorised as food, feed or for cultivation until its safety has been clearly established.

Glyphosate in YOUR food – How safe is “safe”?

People and farm animals can be exposed to glyphosate residues in their food and feed. Some uses on farms significantly increase the chance and level of exposure, for example dessicating (eg, drying) cereals, oilseed rape (canola) and legumes close to harvest. GM crops tolerant to glyphosate can be sprayed numerous times during the growing season. 

The toxicology of glyphoPathways of environment and health impacts of glyphosate.sate is complex because the weedkillers used in fields contain adjuvants (chemicals that make herbicides more effective) that may be more toxic than the glyphosate itself or may increase its toxicity. These formulations are trade secrets, so the companies involved do not divulge specific chemical compositions, which makes studying toxicity difficult. In addition glyphosate breaks down to form aminomethylphosphonic acid (AMPA), which is toxic in its own right. Several peer reviewed papers suggest that glyphosate may be an endocrine disrupting chemical, so extremely small quantities could have disproportionately large effects.

Maximum residue levels (MRL) for pesticides in foods are agreed internationally and then adopted by the EU (pdf), sometimes with amendments. MRLs facilitate trade (imported products with residues exceeding MRLs can be refused entry by receiving countries) and are claimed to protect consumers from harmful levels of pesticide residues in food. MRLs are designed with a built-in “safety margin” of 100 times the acceptable daily intake (ADI) for glyphosate, but this does not take into account any endocrine disrupting effects, and questions remain about long-term low-level exposure to glyphosate alone or in "cocktails" of other chemicals.

GM Freeze reviewed the UK Government data on Glyphosate Residues in UK Food 2011 and found residues reported in wheat/bread and pulses, including MRL breaches. Dried lentils breached MRLs in 16 out of 54 samples, and other dried pulses also breached MRLs. Perhaps more worryingly there is no MRL set for bread despite the use of glyphosate to dessicate wheat and the repeated presence of glyphosate residues in both bread and flour.

n 2012 GM Freeze again reviewed the UK Government data on glyphosate residues in food. Residues were found in bread/bakery products, noodles and beer (pdf), the majority of which were probably the result of crop desiccation. This was reported in the Ecologist. There were no MRL breaches reported in the 2012 samples, but the outstanding questions about the safety of glyphosate means MRL breaches are not the only concern.

lyphosate is also in our water. In 2011 Spanish researchers confirmed the presence of glyphosate in groundwater. At one site the average concentration of glyphosate exceeded the limit set by EU drinking water regulations by more than four times. Also in 2011 the US Geological Survey (USGS) revealed that glyphosate and its breakdown product AMPA are frequently found in rainfall and rivers in the Mississippi Basin.

In 2013 the US FDA substantially increased the MRL for glyphosate in a range of crops. The MRL for soyabeans was doubled to 40mg/kg, and MRLs for forage and hay were raised to 100parts/million. This was not the first major increase in glyphosate MRLs – when GM soya came on the market in the 1990s the MRL for glyphosate in food was raised 200%. Monsanto has applied to the EU to increase the MRL for glyphosate in lentils some 100-150 times.

(For full detail of images of how glyphosate works in plants and soll and the pathways of environment and health impacts of glyphosate see our report.)