The problem of pesticides

Traces of uregulated chemicals are being found in wine. They may be harmless, or they may be problematic. The problem is, nobody really knows. Sophie Kevany reports. 

Pascal Chatonnet, director, Excell
Pascal Chatonnet, director, Excell

New insight into the contents of a glass of French wine has found traces of at least one illegal chemical, refuelling the debate on pesticide residues.

Chemical cocktail

Residue tests run earlier this year by Bordeaux-based wine analysis laboratory Excell on 300 French wines found pesticide residues in 90% of the bottles and showed traces of carbendazim, a fungicide outlawed in France since 2008. Carbendazim is listed by lobby group Pesticide Action Network as a possible carcinogen and suspected ­endocrine disruptor.

Although experts disagree on whether residues are bad for drinkers, there is growing concern over both their unregulated presence and the paucity of research into the low-dose effects of a group of pesticide chemicals called endocrine disruptors. This year, alongside Excell’s tests, a government report found the French population to have higher levels of various pesticide residues - including many endocrine disruptors - than comparable populations in the US and ­Canada. 

Asked why he thought French wines might contain traces of carbendazim, Stéphane Boutou, analytical engineer with Excell, offered three possibilities. “Either an old stock [of carbendazim] is being used, or, they might have used, say, barrels contaminated with the chemical, or, they might have bought it in another country, like Spain, and used it.” Whatever happened, he said, Excell Lab is not under obligation to report the ­discovery. 

Excell’s full list of residue tests runs to about 200 different substances and includes other banned chemicals such as endosulfan,­ dieldrin, endrin and lindane. Excell’s director,­ Pascal Chatonnet, said although these are no longer used in France, they can find their way into wine from chemically-treated wood structures, for example, found in older buildings­ used to store wine.


One of the reasons few French producers worry about residue levels in their wine is they are unregulated. Although so-called maximum residue levels, or MRLs, exist for other agricultural products, such as fruit and vegetables, there are none for wine. And France is not alone. In Europe, only Switzerland has MRLs for wine. 

For the purpose of his tests, Chatonnet converted the MRLs currently applied to French table grapes, which are measured by weight in kilos, into ones for wine, measured by liquid litre. One of the reasons Chatonnet, who has a PhD in Science and a PhD in Oenology-Ampelology from the University of Bordeaux, is offering such in-depth testing is he believes MRLs will ­become mandatory in the next few years. 

Beyond the issue of MRLs, Chatonnet hopes testing residue levels will encourage produ­cers to reduce the amount of pesticides they use, thereby lowering risks to vineyard wor­kers (the people most at risk from pesticides) and the environment.  Chatonnet also offers to advise producers on pesticide treatment ­options, which grow increasingly complex. The service is called +Nature.  Although Chatonnet is one who believes current residue levels should not concern consumers, he also believes more research is needed. “There is a worrying lack of research into the accumulation effect, and how the [pesticide] molecules interact with each other,” he said. “It’s possible that the presence of several molecules combined is more harmful than a higher level of a single molecule.”

Hans Muilerman, chemicals officer for the European branch of Pesticide Action ­Network (PAN), said little is known about the toxicology of low doses because most ­research focuses on high doses. The dangers of ­­low- dose­ exposure mainly concern ­children and foetuses. Muilerman said French and Italian grapes tend to be very polluted, compared to grapes from Chile or South ­Africa, based on a range of tests carried out by PAN Europe. “The reason seems to be the climate. The climates in Chile and South ­Africa are more favourable for growing grapes, more wind, for instance, ­creating less ­fungi problems,” said Muilerman.

Back in 2008 PAN tested 40 European wines for carcinogens, developmental ­or­ ­­reproductive toxins, and endocrine disruptors. The study, called ‘Message in a ­Bottle’, found the seven bottles of Bordeaux used in the sample ­contained the most chemicals, and some of the highest doses. Looking at Chatonnet’s list of residues tests, Muilerman­ said the endocrine disruptors included bifenthrin, ­iprodione, as well as “some of the “azoles group” including ­cyproconazole.

In his own vineyards, Chatonnet, who is also a winegrower, uses the French ­‘agriculture raisonée’ protocol - which ­limits but does not forbid chemical treatments. For concerned drinkers, ­organic and ­‘agriculture ­raisonée’ wines seem to provide a useful alternative. “We get hundreds­ of chemicals fed into our bodies every day, so combination and accumulation are both problems. If you can reduce chemicals, do it. We know almost nothing about these chemical cocktails,” he said. 

The 10% of wines tested by Chatonnet­ that were negative for residues were ­either ­organic or ‘agriculture raisonée’. He warned, however, there was also a chance those wines simply didn’t have the chemicals he was ­targeting, or the doses he was testing for.



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