New research by scientists from the University of Canterbury in New Zealand has confirmed that glyphosate makes disease-causing bacteria resistant to important medical antibiotics. This comes at a time of mounting concern over glyphosate and products like Monsanto’s Roundup which contain it. The World Health Organization has classified it as a probable carcinogen and EU member states again failed to reach agreement about its future at their meeting on 9 November, 2017. A last-minute compromise solution is widely expected, but should this fail to materialise glyphosate’s licence will run out across the EU on 15 December, this year.

As has been widely publicised, the World Health Organisation has classified glyphosate as a probable carcinogen. Largely on this basis the European Parliament voted for a complete phase out of its use by 2022. Despite this the European Commission (EC) is trying to get members states to re-licence it, but the most recent attempt at a compromise has also failed. Originally glyphosate was due to be re-approved for a further 15 years. After the WHO announcement the EC reduced this to 10 years. When this failed they proposed a 5-year extension, but this too has been rejected, with some countries still wanting a 10-year licence, others arguing for less than 5 years and a number abstaining.

Glyphosate, the active ingredient in Roundup, is the world’s most widely used herbicide. It has also been promoted as one of the safest pesticides on the market, which may have encouraged complacency about the need to follow safety precautions when using it on farms, allotments or in gardens.

Despite official assurances about the safety of Roundup and other formulations containing glyphosate, campaigners, and a small number of scientists, have been raising detailed issues about its safety and that of glyphosate for many years. One of the earliest was a paper by Caroline Cox, Responding to a Chemical Goliath, published in the Journal of Pesticide Reform in 1998.

Amongst other issues covered in the paper, are the acute toxicity of Roundup – something seemingly at odds with it official classification – and evidence linking exposure to increased risk of miscarriages, premature births and cancer. This paper also raised concern about some of the other chemicals included in weed killers which help to make the active ingredient stick to plant leaves, or to give it other desired properties.

Claims have now been made that glyphosate is contributing to a wide range of health problems, some highly speculative, others based on research which is suggestive, though not conclusive evidence of a link. These include advocates of organic farming who have linked both glyphosate and GM crops which depend on them, to the overall deterioration of health in the US, in a 2014 paper; and a senior researcher from the respected Massachusetts Institute of Technology who is linking significant increases in the incidence of autism in the US with the high use of glyphosate, based on a small number of studies, including one that has found higher than average levels of glyphosate in the urine of children with autism.

While all these claims have their critics, the problem for commodity crop producers who have been encouraged to build their production systems around the use of glyphosate, is that even if many of the claims being made against glyphosate turn out to be spurious, past assurances about the overall safety of the chemical, alongside its close to universal use, look increasingly suspect.

Onto this scene comes evidence linking glyphosate to yet another health problem: antibiotic resistance. Previous research had shown that glyphosate could trigger antibiotic resistance but, the new research, published last week during World Antibiotic Awareness Week in the open access journal Microbiology, has now confirmed this and also confirms that two other widely used herbicides, Kamba and 2,4-D, which contain the active ingredients dicamba and 2,4-D respectively, have similar effects.

In all three cases the effect was found at levels significantly lower than those at which these chemicals are applied to crops, but not as low as the levels currently found in food and some water supplies.

Antibiotic resistance is a growing global problem with multiple causes. The final report from the Review on Antimicrobial Resistance, set up in the UK under the chairmanship of Lord Jim O’Neill, by former Prime Minister David Cameron, estimated that by 2050, unless we take decisive action now, the cumulative economic impact of antibiotic resistance on the global economy will be in the region of $100 trillion, with 10 million people a year dying from untreatable diseases and many times this number incapacitated or unable to have operations due to the risk of infection.

The New Zealand researchers have also partially answered a question left hanging by the earlier research. Do any of the other chemicals included in herbicide formulations, such as those identified by Caroline Cox back in 1998 as being highly toxic, also contribute to antibiotic resistance?

They looked at two of these, Tween80 and CMC. Alarmingly, since both of these are also permitted as emulsifiers in foods like ice cream, the answer is that yes they do.

The researchers have so far only tested the effect of these chemicals on E. coli and salmonella bacteria and against a limited number of antibiotics, but this is clearly an area which merits a wider international research effort and extreme caution until more is known.

Genetically engineered Roundup Ready crops allow farmers to spray the crop as it is growing as well as before it is planted, to control weeds. Farmers in countries like the UK where GM crops are not grown commercially also use Roundup, but can only do so before the seedlings emerge, on the crop in the period before harvest to speed up ripening and after harvest to control weeds – a practice which has led to concern about the amount of the chemical left on the wheat.

The Sustainable Food Trust contributed £18,000 towards the research carried out by University of Canterbury team because we felt that important questions needed to be answered. We had no input into the study design or the research, and did not see any drafts or a copy of the research paper until it was published.

Cartoon: Jake Tebbit

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