Glyphosate - The villain of a generation, or hopelessly misunderstood?

In March 2015 the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” Group 2A. Since then, glyphosate has been justifiably scrutinised by politicians, the media, and the public in both Europe and the US and in US courtrooms who all want an answer to the burning question that still, almost 5 years later remains. ‘Does glyphosate cause cancer?’

Under mounting political pressure, not just at European level, but for most of our clients, at local authority level to find alternatives to glyphosate, this article aims to look at the background of glyphosate and explore the classification, and in doing so look to answer some of the more relevant questions like ‘what are the alternatives?’; ‘are they as effective?’; ‘are they cheaper?’ and most importantly ‘are they safer?’


So, what is glyphosate and where is it used? Glyphosate was developed by Monsanto (a name that people love to hate due to their involvement in GM crops – but that’s a whole other article!) in the 1970’s and were for a long time, the sole manufacturer of glyphosate products until their initial patent expired in 1991. However, still having a patent in place against the isopropylamine salt meant that Monsanto maintained exclusive rights in the US, until September 2000. Until this patent expired, glyphosate had been solely marketed by Monsanto under different derivative names of Roundup, but henceforth has been available to purchase under a variety of names and from a variety of manufacturers. Some common formulations here in the UK amenity sector that readers may be familiar with are ‘Rosate’; ‘Clinic’ and ‘Gallup’, and some clients who have not had any formal pesticide training, are often surprised to learn that these all contain glyphosate, the same active ingredient found in Roundup.


In the amenity sector our main uses of glyphosate are for treating weeds on hard surfaces, in shrub beds, and around obstacles in grass to reduce the requirement for strimming, but the amenity sector is vast, so these treatment scenarios can and do occur on highways, in parks and cemeteries, on railway lines, at airports, sports stadiums, hotel grounds, universities, schools and to treat invasive weeds to name a few. If we then consider the use of glyphosate in global agriculture and take into consideration that almost 2.2million hectares of land in the UK alone are sprayed with glyphosate as a desiccant prior to harvest, when combined with our usage in public spaces and indeed in private gardens by domestic gardeners, our exposure to glyphosate is somewhat unavoidable in modern life. Furthermore our reliance on it to aid crop yields and thus our food supply mean that a ban on glyphosate, certainly in agriculture, would have profound effects on our economy. If you would like to read further about the impact of a glyphosate ban on the UK economy, the crop protection association in conjunction with Oxford Economics have published a summary report here


But if glyphosate is everywhere and our economy relies on its use, what does the IARC classification mean, and should we be concerned? To answer this, it’s important to look at the IARC’s classifications and their role in advising the World Health Organisation. The IARC is an agency of the World Health Organisation which aims to identify causes of cancer by means of examining scientific evidence to recognise carcinogenic chemicals, physical agents and lifestyle factors. It does not look at the dosage of a substance required to have a carcinogenic effect, the mode of action as to how the substance would come into contact with humans or enter the body, or how likely it is that exposure to a substance will cause a carcinogenic effect. To put this into perspective, sunlight in the form of UV rays is classified as a group 1 carcinogen by the IARC, it’s fair to say that most of us are highly likely to be regularly exposed to sunlight, however avoiding it is not only impractical but could lead us to Vitamin D deficiency, which can lead to bone deformities. Which is why the IARC or the WHO do not recommend we avoid it entirely! Other known carcinogens (group 1) include (but are not limited to) alcohol, tobacco smoke, diesel emissions and processed meat. Contact with many of these items its fair to say is a regular, if not daily occurrence for many of us.


So, let’s look at glyphosate’s classification. The IARC define a type 2A carcinogen as:

“This category is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. Limited evidence means that a positive association has been observed between exposure to the agent and cancer but that other explanations for the observations (technically termed chance, bias, or confounding) could not be ruled out”


Therefore it appears that the IARC have observed an association between glyphosate exposure and cases of cancer, but they cannot categorically say that it is the glyphosate that has caused this association, and are unable to rule out other factors. This classification also applies among other things, to shift work, caffeic acid (found in coffee, apples, pears berries and wine) and occupational exposure as a hairdresser. There is an association according to the IARC, but these factors are not known causes of cancer at present based on current available evidence.


To give an example, if a hairdresser developed cancer, should we jump to the conclusion that the cancer has been caused by their occupation, because the IARC say ‘occupational exposure as a hairdresser’ is a probable carcinogen? Or should we think logically and look at their other lifestyle factors – do they drink alcohol regularly? Coffee? Eat a bacon sandwich every day? Walk to work on polluted roads whilst exposed to sunlight!? Should we ban hairdressing in the interest of public health because of this correlation? Similarly, if a farm worker, who has been applying glyphosate for a number of years through a tractor mounted boom developed cancer, should we immediately blame the glyphosate, or should we rule out other known carcinogenic factors first? Such as the diesel emissions from the tractor, which are a group 1 (known) carcinogen. And if an operative spends their working life spraying glyphosate in car parks and develops cancer, is glyphosate the likely causing factor? Or should we be looking again at diesel emissions from cars and perhaps other lifestyle factors? Perhaps we should be risk assessing these environments and their pollutants in more detail before sending staff out to work.


Obviously in the examples above, the exposure to the named agent is high as it is through their occupation in all 3 scenarios, and certainly in 2 of the scenarios, exposure to the agent is likely to be daily. Consider then the exposure levels of glyphosate to members of the public, who may come into contact with trace amounts of glyphosate, mainly through their diet, but perhaps also on occasion by passing through a treated area. Do we consider this, a type 2 carcinogen, a larger risk to the public than say, air pollution? Which is reported in the daily telegraph here to have claimed 64,000 lives in the UK in 2015 alone.


Subsequent to the IARC’s findings, in 2016 the World Health Organisation in conjunction with the Food and Agriculture Organisation of the united nations (FAO) concluded that “glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet.” The European Chemicals Agency then in 2017 concluded that the “available evidence did not meet the criteria to classify glyphosate as a carcinogen, as a mutagen, or as toxic for reproduction” And more recently just last month (January 2020) the US Environmental Protection Agency reaffirmed its stance that “there are no risks of concern to human health when glyphosate is used in accordance with its current label. EPA also found that glyphosate is unlikely to be a human carcinogen”


However, despite the evidence available to us, three court cases in the US have been won against Monsanto and although Monsanto have appealed, and in some instances had the settlement amount vastly reduced, there still remains to be concern over the use of glyphosate. Without being in the courtrooms, I cannot begin to speculate on the reasons that the juries have reached the verdicts they have. But understandably, the amenity industry is starting to look at alternatives, and so we should. Innovation and new technology should be at the forefront of everything we do. We should strive to do things more efficiently, and more importantly as safely as possible for our operatives, clients and members of the public and make spending from the public purse as economic as possible. So, what’s on offer? What alternatives can we use that are a viable alternative to glyphosate?


Well, we could remove weeds manually, but if we look at doing this on the scale at which we are currently using glyphosate – for example every pavement and footpath on every road in a London borough, the labour aspect would multiply tens of times over. Further to this, roots would not be removed, and many perennial weeds would simply regrow rapidly and in some cases stronger with root systems establishing in greater capacity and perhaps eventually causing damage to our infrastructure. In order to maintain adequate control from a visual perspective, it’s estimated we would need to carry this out at least 6 times per annum to maintain the same level of control we see by applying glyphosate 2/3 times per annum.


Acetic Acid – or vinegar, there are a number of products on the market now containing this active ingredient, and the products make no secret on their label’s that they are toxic to bees. One which I have to hand as I write states “Dangerous to bees. To protect bees and pollinating insects do not apply to crop plants when in flower. Do not use where bees are actively foraging. Do not apply when flowering weeds are present”. As glyphosate is not classified as toxic to bees, I think that this is reason enough to rule out acetic acid as a viable alternative. But lets also touch on costs… If you apply glyphosate in a knapsack sprayer at 5Litres per hectare, to make the sums easy lets say we’re applying at 200L total water volume, so you’d put 500ml in a 20L knapsack.

At the time of writing you can buy a 5L container of Roundup Pro Active online for £46.00 including vat. So, as 500ml is 10% of that 5L container, the cost per knapsack fill is £4.60, and the cost per hectare is £46.00.

The Acetic acid product I have in hand is currently £41.10 for a 5L container online, however the label tells us to mix 3 volumes of clean water with 1 volume of product. So in that 20L knapsack, you would put the whole 5L container! Therefore the cost per knapsack fill is £41.10 and the cost per hectare (assuming the same volume rate) is £411.00! Approx 9 times more expensive!

Then consider that this product also is not systemic, so wont kill roots, you’ll likely need 6 applications per year instead of 3 and your annual cost per hectare has just leapt from £138.00 per hectare with glyphosate (based on 3 treatments) to a staggering £2466.00.

Now, the calculations above are based on the same volume rate, and works out at approx. 5ml of acetic acid product per square meter. However the acetic product I have in hand states the maximum individual dose as 25ml per square meter. Meaning that potentially, you could apply at 5 times the rate detailed above, at 5 times the cost! Not to mention the added labour incurred by filling up more regularly.


Pelargonic Acid (or other fatty acids) – Again we see the same statement on the product labels of these products: “Dangerous to bees. To protect bees and pollinating insects do not apply to crop plants when in flower. Do not use where bees are actively foraging. Do not apply when flowering weeds are present”, and as if that isn’t enough of a reason not to use it, it’s applied at 22.5L/Ha with each 5L currently online costing £185.00.

So cost per hectare £832.50. More than double again from acetic acid. Label states maximum 4 treatments annually, so annual cost for comparison s £3330.00.


Hot foam – This method is becoming more and more popular, especially within parks where the vehicle that is required to transport the cumbersome equipment can be easily parked adjacent to the area which needs treating.

Although I am told that these machines can have up to a 100m hose, I am yet to see them as a viable alternative to glyphosate on highways, where the vehicle would need to be constantly moving with the operative, who would need to disappear into pedestrian precincts, down narrow alleyways and between parked cars all whilst manoeuvring the hose around corners and obstacles whilst ensuring no trip hazards to the public and no public interference with the machine.

A few of our clients have undergone trials with these machines, and the feedback I have had is that the initial cost, whether the machine is purchased or hired, is high and the operation is slow. One told me that ‘although the results seemed impressive, you’d never do the whole borough with one’. I must admit though, this technology has grabbed my attention and out of all the alternatives it does seem to be the most viable. It claims to have some effect on roots, although I can’t vouch for that.

My main concerns with this system and the reason I remain a sceptic is 1. Boiling water in public spaces when weeds are growing – what implications does this have on risk assessment for public exposure?

2. What is the environmental impact? By using this are we effectively pouring boiling water on beneficial insects and other beneficial organisms? The foam is biodegradable, but so is glyphosate. And furthermore, this requires a vehicle to transport the system. Granted this could be a low emission vehicle or no emission vehicle even, but then the foam itself is heated by a generator powered by guess what – yes, diesel!

So, are we simply substituting a ‘2A - probable carcinogen’ in that of glyphosate for a ‘1 - known carcinogen’ in diesel emissions from hot water/foam systems? It seems that way! Maybe a case of better the devil you know for our local politicians.


So what should we do? We could not do anything. We could leave the weeds to grow and flourish, what would be the harm in that? Public perception plays a huge part, should we try to change that? Should people be more accepting of vegetation on our streets, in our parks, housing estates, schools? Perhaps. Although having travelled the country and seen areas that have been neglected in terms of grounds maintenance for years on years, in my opinion leaving areas such as rear alleyways and garage blocks unattended to, only attracts litter, rodents, fly tipping, graffiti and eventually other forms of anti-social behaviour. Weed control therefore, again in my opinion is one of the first steps in maintaining a sense of pride in the places we live and work. It aids our local authorities in creating a clean and aesthetically pleasing foundation on which to build a pleasing environment for us to experience, and most feel that they have a responsibility to deliver that to their taxpayers.


What I personally think, and again, this is my opinion, is that we should take a common sense approach. The agencies that regulate us have, after extensive research on our behalf, approved glyphosate products for use until the end of 2022 in Europe. This does not mean that glyphosate will be banned thereafter, it means that it will undergo a re-approval process and the European commission will vote either to re-approve, or to withdraw based on the available evidence at that time.


I’m sure that we will see, and I hope that we do see technologies and innovations coming to market herbicidal or otherwise that will perhaps offer a systemic solution to weed control at a cost that won’t bankrupt our local authorities or have a detrimental effect on our food supply. In the meantime, however, we will continue to work with our clients to ensure treatments are effective, controlled, targeted and efficient, leading to a reduced overall need for pesticide use and keeping emissions to a minimum with pedestrian only operatives. All the while ensuring that products are used by professional, qualified staff in accordance with the product labels and overseen by BASIS qualified advisers. Only by working with our clients in this way, can we strive to operate in the safest possible manner, receive and give up to date guidance and offer the best all round solution for safety, efficacy and cost.

Acetic acidCarcinogenGlyphosateMonsantoPelargonic acidRoundupWeed spraying