No, I didn’t know what it is either … until recently.
And no, I am not a chemical engineer and I have no idea how to translate 1,1’-dimethyl-4,4’-bipyridylium ion into any language I would understand. But I do know its common name, which is paraquat; or, perhaps, I should say that I know the name by which gardeners bought it years ago, before it was banned, not just in the United Kingdom, but throughout Europe. I used to use it in my garden, for it is … was, in the UK … a very effective weed-killer. Our American cousins still use it as a herbicide; and it is used there, because, to quote the website of the Paraquat Information Center: “Paraquat is a herbicide to control a very broad range of weeds in more than 100 crops, including cereals, oilseeds, fruit and vegetables, growing in all climates. Weeds shade crops, take their water and nutrients, and make harvesting difficult. The leading manufacturer of paraquat is Syngenta, which (as ICI) developed the active ingredient (AI) in the early 1960’s. Since then, paraquat has made possible many innovations in sustainable farming systems, based on its simplification of crop production by effectively controlling weeds and, in doing so, removing the need for ploughing to bury them. This has freed up farmers’ time and also helped care for the soil. Paraquat is one of the most widely used herbicides in the world. It has been approved for use by authorities in nearly 90 countries. When used as recommended, paraquat is effective and safe to users, consumers and the environment.” (The Paraquat Information Center published this on behalf of Syngenta Crop Protection AG, a company based in Switzerland, where the use of paraquat has been banned since 1989.)
So why is such an apparently excellent herbicide banned throughout Europe? Well, European governments are persuaded by the now-significant body of research which links paraquat use with Parkinson’s disease. Here is another transatlantic quote, this time from the website of the United States Environmental Protection Agency (EPA or sometimes USEPA), an agency which was created for the purpose of protecting human health: “There is a large body of epidemiology data on paraquat dichloride use and Parkinson’s disease.” Paraquat is also highly toxic to humans; one small sip can be fatal and there is no antidote; and American data also suggest that paraquat is corrosive to the skin and eyes. Can be nasty stuff!
Let’s be perfectly clear about the use of paraquat in the United States. It is available strictly for agricultural use by registered and appropriately-trained users; it is not available in garden centres and gardeners are not allowed to use it. And let’s also be clear that it is illegal to import paraquat into the United Kingdom, although a lot of it is made for export right here in Yorkshire by Syngenta. But it took me less than two minutes to find an advertisement on the web offering paraquat in 1-litre packs at the knock-down price of only US $2.50 per litre – and you’ll find it hard to persuade me that an American farmer will buy it in 1-litre packs!
So what do I use nowadays to kill weeds in my garden? In common with innumerable gardeners world-wide, I tend to prefer Roundup, the world’s most popular weed killer. But US farmers are now reporting that weeds are becoming resistant to Roundup, and the use of paraquat as an alternative is on the rise, especially for soybean fields. Although many people think that the European Union is over-cautious in its approach to hazardous chemicals, paraquat is not included in the list of chemicals identified as ‘hazardous’ in the Rotterdam Convention - a multilateral treaty to promote shared responsibilities in relation to the import and use of hazardous chemicals. This omission would allow a post-Brexit UK government to permit paraquat to be used here again. For our health’s sake, I sincerely hope that it will not!sandy