Most gardeners have used glyphosate. Even if it’s not the branded version (Roundup) everyone has probably used one of the many generics. Spraying a dandelion growing through the patio, bindweed taking over the fence, or just something growing somewhere where it’s not wanted. Grab the bottle, give the plant a spray and move on. Maybe wear gardening gloves, maybe make sure the cat is nowhere nearby but who wears full on protective clothing or goggles? Are you ready for Roundup?
Well, you may wish to reconsider how (actually “if”) you use it. And perhaps ask your local council to do likewise.
What is glyphosate?
Glyphosate is an organophosphate, chemicals that poison mammals, plants, insects, and microorganisms – pretty much everything they encounter.
Glyphosate is the world’s most widely used herbicide. It’s only supposed to kill plants. But guess what? It turns out it kills – and damages – lots of other things as well.
Over two billion kilos of glyphosate are sprayed onto plants around the globe every year. But glyphosate isn’t killing plants as effectively as it used to because the weeds are adapting and becoming resistant. The more that gets sprayed, the more resistant the weeds get, and so even more gets sprayed. And of course it doesn’t just stay on the plants. It gets into the soil and – because it’s water soluble – into the water (and the rivers and the oceans and the rain), and residues get left on the plants that we eat and the water that we drink, and yes, it gets into our food and into us.
What does it do?
Glyphosate blocks the shikimate pathway.
The shikimate pathway is a series of enzyme reactions. It is how plants, bacteria, fungi, and other organisms make certain proteins. So when glyphosate blocks the shikimate pathway it stops the manufacture of those proteins. And as those proteins are essential to life, the plants (and bacteria and other organisms) die.
In 1974, when glyphosate was launched onto the market, Monsanto assured the world that their shiny new product would only kill plants, because only plants have the shikimate pathway (in 1974 the importance of bacteria, fungi and other microorganisms to the environment was not well understood). But it turns out that it is highly toxic to a whole range of other things.
Glyphosate massively reduces the microbial diversity and ecosystem in soil. Damage to soil ecosystems impacts the health of any plants that manage to survive the toxic spray. It turns out, plants and the soil microbiome have an amazing symbiotic relationship where plants pass nutrients like sugar, protein and fat to the microbiome, and the microbiome passes minerals to the plants. So less microbiome, less minerals in plants, and the plants don’t grow as healthily. And animals (including us) which eat the plants don’t get the same kind of nutrition out of them that we would, if only they hadn’t been sprayed with herbicide.
When more complex organisms are exposed to glyphosate the consequences are just as grim. Reproduction in earthworms crashes. Zebra fish suffer severe DNA damage. Honeybee sperm is destroyed. Rat livers are irreparably damaged. Sea urchins and sea snails lay fewer eggs, and even fewer hatch. And there are negative effects seen in humans too.
Human health impacts
Just like the soil microbiome, the human gut microbiome contains a mixture of microorganisms. And, just like the soil microbiome, the human microbiome is negatively impacted by exposure to glyphosate. Because a lot of the bacteria in our gut use the shikimate pathway. And as previously discussed, the bacteria in our gut have a huge impact on our health and wellbeing.
There is a lack of agreement amongst global agencies about the potential toxicity of glyphosate. The International Agency for Research on Cancer (an arm of the World Health Organization) says it probably causes cancer. The American Environmental Protection Agency says it doesn’t cause cancer. And, in a recently published statement, the European Food Safety Authority has stated that there are “no critical areas of concern, although there are data gaps”.
Although some researchers claim that the increase in a lot of different cancers that seems to be related to glyphosate is untrue, as of May 2022, Monsanto (and now Bayer, who bought Roundup in 2018) had settled over 100,000 lawsuits claiming glyphosate caused cancer. It has cost them around £8.6bn ($11bn USD) so far. Industry doesn’t pay out unless it is trying to hide something – or has been caught out in serious wrong-doing.
It’s not ‘just’ cancer though. Glyphosate has also been linked to the development of a range of neurological diseases including Alzheimer’s, Parkinson’s, ADHD, and autism.
We are semipermeable
The whole of the inside of our bodies is lined with thin membranes that are semipermeable. A bit like a shape sorter toy, but a lot more complicated, and a lot smaller (think microscopic), these membranes let specific substances through, and keep other things out.
We have semipermeable membranes inside our arteries and veins that let nutrients and oxygen out into our cells and absorb carbon dioxide and waste products for disposal. Inside our gut, the semipermeable membrane lets nutrients, hormones, and messenger chemicals through (which get carried around the body in our blood) and absorbs water into the gut.
What makes all these membranes semipermeable are things called tight junctions. A bit like microscopic biological Velcro, tight junctions stick a line of cells together, only letting certain substances through the gaps. We need to keep those junctions nice and tight because, if they get slack, then stuff gets through that really shouldn’t.
Guess what? Glyphosate makes tight junctions floppy (a lot more technical than that, just trying to keep it relatively simple). In our blood vessels, ‘floppy tight junctions can lead to plaque buildup. Slack junctions in the gut are sometimes called ‘leaky gut’ which is linked to increased risk of food allergies, bloating, gas, and cramps as well as inflammatory conditions like IBS. And, if the junctions in the semi-permeable membrane surrounding our brain get baggy, there is an increased risk of neurological disorders.
Most of the world has a serious problem with vitamin D – we just aren’t getting enough. And one of the causes might just be glyphosate.
When we eat food, or take supplements containing vitamin D, or make vitamin D in our skin, it needs to get converted from its inactive form to its active form. That conversion needs some enzymes called the cytochrome P450 enzymes … you guessed it – glyphosate disrupts the cytochrome P450 enzymes so less vitamin D gets converted into the active form.
Glyphosate use in the UK
According to a survey carried out for the Health and Safety Executive, in 2021 nearly 254 tonnes of glyphosate was sprayed across 2,445 square kilometres of farmland in the UK. Nowhere near levels in the USA but, still, that’s up 16% since 2016. And that’s ‘just’ on farmland: it doesn’t include what gets used by local councils spraying to “control” verges, and what individual gardeners use.
Quite a few councils have either banned the use of glyphosate altogether, or are in the process of phasing out their use (along with other pesticides). It’s definitely time to start putting pressure on more councils to do the same.
Meanwhile, in your own garden, get down and do some old-fashioned weeding. Or learn to live with plants in places that you didn’t plan on them being.
T C Callis’ articles are very well researched, and always come with a wealth of references. If you are interested in following up anything in the article, don’t hesitate to contact us at Kent & Surrey Bylines for more information.