Walking the pavements of Brighton, you’re bound to see weeds sprouting through the cracks, writes James Williams. While these may seem harmless, even quaint or charming to some, they can cause real problems if left unchecked. Slabs of the pavement can crack and become uneven as weeds take root, creating tripping hazards.

Weeds can damage building foundations over time. That’s why many cities and towns use powerful herbicides containing glyphosate (the main ingredient in the weedkiller Roundup) to control weed growth on pavements, in parks and other public spaces.

But glyphosate has become controversial in recent years. In 2019 Brighton proposed a ban on using the chemical weedkiller. But since that ban the weeds have not been systematically tackled and now, they are causing real problems. This has led to Brighton Council proposing to reintroduce the weedkiller once more. So, what are the problems with the weedkiller and how could it be used more safely?

Scientific studies have found associations between glyphosate and cancer, raising concerns about the safety of dousing our public spaces in this chemical. Cases of cancer linked to glyphosate exposure have led to multi-million-dollar lawsuits against Monsanto, the developer of Roundup, in the US. With glyphosate use under increasing scrutiny, those charged with keeping our streets and public spaces tidy must find solutions to balancing weed control with public health.

On the surface, glyphosate seems an ideal herbicide for cities to use. It’s effective at killing the toughest weeds yet is it claimed the chemical breaks down quickly in the environment without leaving toxic residues. This would suggest limited risks to the public. But the science around it is not so clear cut. While regulators continue to assert glyphosate’s safety when used as directed, some scientific research raises questions.

A 2015 WHO analysis labelled glyphosate a “probable carcinogen”. Other researchers suggest it may harm our endocrine system. It works on weeds by stopping the plant from absorbing nutrients from the soil as well as preventing it from making certain proteins needed for plant growth. The chemical is absorbed by the leaves, then carried internally to the roots. Studies suggest glyphosate may harm bees, monarch butterflies, and other beneficial insects.

While debate continues around glyphosate’s exact toxicity levels for humans, the mounting evidence should give the council pause when considering its widespread, liberal use. There are good reasons to curtail unneeded use of glyphosate products in areas frequented by the public.

One option being looked at is controlled droplet application. This is binding the weedkiller with an oil emulsion so it sticks to the leaves of plants and doesn’t simply run off the surface and into the soil. These droplets are applied directly to the plants.

A second method uses Integrated pest management (IPM) programmes to take a more cautious, tailored approach. IPM utilises non-chemical solutions first, like planting native grasses that out-compete weeds along in public areas and maintenance methods like mowing or hand weeding where practical. Many experts recommend products with acetic acid (vinegar) as an alternative.

Hammersmith and Fulham Council in London trialled alternatives after groups raised concerns. Though more costly, hot foam treatments proved effective and avoided toxins. They banned the use of glyphosate in 2016. Edinburgh City Council is banning glyphosate use in public areas like parks, playgrounds, and schools where children are present. Glastonbury Town Council discontinued use on footpaths and streets in 2015, the first council to do so, to protect bees and human health. It is possible to have a non-hazardous chemical way of controlling weeds, but it will need investment in equipment and people.

There is no easy or absolute answer on glyphosate use in urban areas. Glyphosate-free management is challenging, especially on infrastructure like railway lines and large roads where alternative methods may be infeasible or more ecologically harmful. But councils should continually be on the lookout for sensible ways to limit exposure to the public, especially children who are more vulnerable. It’s time to reassess when and where broadcast spraying of this potent chemical is appropriate in areas meant for public enjoyment. Adopting practices like IPM, hot foam or alternative safe chemicals that minimise reliance on glyphosate is a prudent step for any council to consider.

Dr James Williams is a senior lecturer in education at Sussex University