The plight of the bumblebee
Spotlight on: insecticides
Arthur C. Clarke once wrote that “any sufficiently advanced technology is indistinguishable from magic.”
If one were to explain to an early Neolithic farming community the many benefits accrued to humanity via the use of pesticides, accusations of sorcery would surely soon follow. And yet, since their introduction, these often-disparaged chemicals have led to increased crop yields, improved food safety and human health, and a worldwide boost in quality of life.
Since their humble origins more than 4000 years ago in ancient Sumer, pesticides have diversified into a broad portfolio of more than 80,000 chemical substances, classified depending on their application. Herbicides (weed killers) are the largest subcategory, making up around 40 percent of global use, whilst insecticides designed to eliminate pest insects like beetles, mites, moths, aphids, and flies make up around 33 percent.
Whilst insecticides have proved effective against pest insects, they have also proved harmful to the wider ecosystem, including to beneficial insect life such as pollinators. Pollinators are not usually targeted by farmers, but they can still end up ingesting insecticides due to contamination. For example, phorate – an organophosphate used to control a wide range of insects and nematodes - can produce metabolites that can persist in soils, ultimately leaching into waterways and contaminating floral plants.
A 2013 report concluded that insecticides are likely to be impacting a broad range of non-target taxa.
“Reported levels in soils, waterways, field margin plants and floral resources overlap substantially with concentrations that are sufficient to control pests in crops, and commonly exceed the LC50 (the concentration which kills 50% of individuals) for beneficial organisms,” the study found. “Concentrations in nectar and pollen in crops are sufficient to impact substantially on colony reproduction in.”
Insecticides can also pose a serious threat to human beings. Long-term exposure to pyrethoids, for example, has been associated with a higher risk of all-cause and cardiovascular disease mortality, whilst acute oral phorate exposure can cause blurred vision, nausea, convulsions and, at high doses, death.
In recent decades, pesticide use worldwide, including the use of insecticides, has grown. Brazil, Canada, and Argentina have shown particularly strong growth, whilst China and the USA have consistently used high amounts of insecticides since 1990. This year, at least 3.5 million tonnes of pesticides will be used worldwide, with some estimates as high as 4.6 million tonnes.
Many insecticides can persist in soils, endangering pollinators by way of waterways and floral plants.
The Legislative Landscape
Because of the risks posed by insecticides and other pesticides, legislators around the world have imposed regulations on their use. The European Union has set strict limits on acceptable residue levels of phorate in various foodstuffs – as low as 0.01mg/kg – and issued outright bans on many other insecticides, including three neonicotinoids in 2017 – clothianidin, imidacloprid, and thiamethoxam and another – thiacloprid – in October 2019.
In September of this year, the French government attracted heavy criticism after it temporarily reversed the ban of these neonicotinoids until July 2023, in order to save its struggling sugar beet industry from a jaundice virus spread by green aphids. The decision was made possible by a derogation built into the European Commission’s legislation, which allows for the use of neonicotinoids in response to “a danger which cannot be contained by other reasonable means.”
Meanwhile, across the Atlantic, the EPA opted not to follow the European Commission’s example, allowing the use of the aforementioned neonicotinoids to continue. “Pesticides banned in the EU account for more than a quarter of all agricultural pesticide use in the USA,” says Nathan Donley, senior scientist at the Center for Biological Diversity. “The majority of pesticides banned in at least two of these three nations [Brazil, China, and the EU] have not appreciably decreased in the USA over the last 25 years and almost all have stayed constant or increased over the last 10 years.”
In the USA, phorate is classified as a restricted use pesticide (RUP), meaning it is not available for purchase or use by the general public. According to the EPA, “RUPs have the potential to cause unreasonable adverse effects to the environment and injury to applicators or bystanders without added restrictions.” Despite these restrictions, phorate is still widely used in the USA, with 80% of annual use applied to corn, potatoes, and cotton.
There is some evidence that change is afoot, however. The ‘Protect America’s Children from Toxic Pesticides Act of 2020’, introduced by two senators in May of this year, seeks to instigate “the most comprehensive reform of US pesticide rules in nearly 25 years”, and would, if passed, ban organophosphates and neonicotinoids in order to protect both human health and the environment.
China, the world’s largest producer and consumer of insecticides, has in recent years made strides towards reducing its output. The nation has completely prohibited the use of phorates in the production of vegetables, fruit trees, tea, and Chinese herbal medicine, and has announced plans to reduce the use of all pesticides in 2020.
China is the world’s largest producer and consumer of pesticides – but that could change.
Science for a Safer World
Within countries and between them, the regulatory landscape surrounding the use of phorate and other insecticides is always changing. In an industry defined by shifting legislation, the central role that science plays cannot be overstated.
Scientists around the world must be able to accurately detect and measure pesticide residues, both in order to ensure regulations are being met, and to inform legislators as to developments in our understanding of the effects of these substances on human health and the environment.
To further assist and keep pace with changes in this dynamic sector, Dr. Ehrenstorfer has recently added more than 60 new insecticide and metabolite reference materials to our range, including an expansion of our phorate range.
Covering all formats and all major categories, our neat and single solutions are produced in alignment with changing regulations, allowing laboratories to monitor the use of legal pesticides, prevent the use of banned substances, and help generate data to support regulatory bodies in setting future regulations.
We produce both native/parent compounds and major metabolite compounds to allow labs to monitor insecticides that are less stable when digested or exposed to the environment.