Arsenic is the ultimate tasteless and odorless killer. When you consider its relationship to wine, haunting, decades-old headlines like “POISON WINE FELLS 11; French Woman Said to Have Put Arsenic in Vats” (1955) and “300 French Sailors Poisoned By Arsenic in Wine Rations” (1932) may creep to mind.
But the poison’s relationship to vines and agriculture is far cozier than you might realize.
“[Arsenic] was the most common form of pesticide until [World War II], but it was still used in the 1970s and the 1980s,” says Dr. Carolyn Cobbold, Ph.D., research fellow at Cambridge University and author of A Rainbow Palate. “Because of the toxicity of arsenic, it has been used as a pesticide, fungicide and herbicide for a long time.”
Before it found its way into the vineyard, arsenic had a history similar to many other naturally occurring elements now known to be lethal, including lead. It was used as medicine to treat skin and lung diseases across ancient civilizations, and in skin-lightening cosmetics in Victorian England.
“It’s really important to note that arsenic tends to be found throughout the world with other metal deposits,” says Cobbold. “So where you find gold, silver, copper and lead, there’s often arsenic.”
Arsenic: The Total Package?
Arsenic’s prominence as a treatment in American vineyards, orchards and cotton fields began sometime in the late 19th century. Controlling mold and pests in vineyards was a tricky task and many American growers looked to the chemical treatments that had been used effectively in Europe.
“In most vineyard scenarios, the biggest issue is molds,” says Andrew Waterhouse, Ph.D., wine chemist and professor of enology at University of California, Davis. “So gray mold or powdery mildew or downy mildew—those are the big three that have been scourges in viticulture for hundreds of years. So, if they were using arsenic in a vineyard, it was probably because it was effective against some of these molds. [Arsenic] is basically toxic to everything.”
These treatments included organic and inorganic arsenic compounds like monosodium methanearsonate, calcium arsenate, lead arsenate and copper arsenate. They were often commercialized with catchy names like Paris Green.
“If you look back on where it started, you get stories that you can’t necessarily source, but tales like some French farmer spilled Paris Green, which is copper arsenate, on a field and noticed it killed the insects and thought, ‘Aha! Insecticide,’ ” says Cobbold.
An inorganic compound, Paris Green’s bright hue was a product of the blend of arsenic, copper and lime oxide. This particularly deadly combination, also known as copper acetoarsenite, was used to rid vineyards of molds, as well as preserve bodies for burial, create vibrant hues in paintings and wallpapers and even kill Parisian sewer rats—a true all-in-one product.
But whatever form arsenic took, there was little understanding of the lasting effects these chemicals could have on the land or to the people who used them.
“Because [arsenic] was often applied near the barn, they would dump the leftover pesticide when they were done,” says Waterhouse. “So there was usually a hotspot where they would dump the little bit leftover every time they would spray.”
Cobbold adds that arsenic contamination in soil is “pretty widespread worldwide,” and it’s likely that arsenates are still used in places where there isn’t as much agricultural oversight.
Unfortunately, the lasting effects of these hotspots and arsenate use have not been studied in depth, and likely never will. According to Jenny Nelson, Ph.D., adjunct professor at University of California, Davis, Viticulture & Enology Department and ICP-MS & ICP-MS/MS application scientist for Agilent Technologies, “eventually, [arsenic present in soil] would be moved around, and diluted with rain, but I do not know for how long.”
Nelson and her colleagues have studied the presence of arsenic in wine, and point to research by Muhammad Ashraf Ali, professor of civil engineering at Bangladesh University of Engineering and Technology, on the topic of whether it would dissipate or languish in soil over time.
“Arsenic is not likely to be dissolved or washed out by flood or rainwater in oxidized condition due to its affinity for iron, manganese, aluminum and other minerals in soil,” writes Ashraf Ali.
Also unclear is just how detrimental organic or inorganic arsenate may have been to the biodiversity and soil health of vineyards since they rose to popularity more than a century ago.
“Although the toxicity of the organic arsenic herbicides are much lower, they’re the ones that when they biodegrade in soil, they become more toxic,” says Cobbold.
Arsenic in wine: A thing of the past?
The good news is that arsenic-based products are no longer used on U.S. or European vineyards or in other types of farming (though it’s worth noting the substance has been replaced by similarly questionable synthetic treatments). By 1905, Paris Green was slowly phased out of use. It caused severe side effects in those who came into contact with it, including chronic illness or death.
It was also discovered how deadly arsenic could be in larger doses. In a 1932 New York Times article detailing the poisoning of some French sailors, many stated that they had been feeling ill for months. When arsenic was found in the wine rations, experts purported it “may be traced to the use of poison to combat blight on the vines or that arsenic may have been introduced to the wines to diminish acidity.”
“[The incident] was reported in papers from New York to Singapore,” says Cobbold. “And it’s quite interesting because if you look at what the experts said at the time, they couldn’t agree where the arsenic came from.”
Other inorganic arsenic-laced chemicals began falling out of favor with the introduction of DDT and other synthetic treatments after World War II. A study from the National Institute of Health’s National Center for Biotechnology Information (NCBI) says that lead arsenate was “phased out after it was recognized that its use was associated with health effects in orchard workers and an increasing concern that arsenic residues on fruits were a public health concern.”
The Environmental Protection Agency (EPA) finally banned “acutely toxic” lead arsenate in 1988, noting its host of gruesome side effects like skin, bladder and lung cancer, severe gastrointestinal damage, general vascular collapse, coma and death. Calcium arsenate and some organic arsenic herbicides, however, are still legal but are highly regulated and not allowed for use on food crops.
While these products had a clear, devastating impact, there’s no data to show just how widespread the health complications from arsenic pesticides, fungicides and herbicides have been.
“I suspect they weren’t using a lot of protective gear [at the turn of the century], so they were probably ingesting [the arsenic],” says Waterhouse. “But keep in mind at the same time people were applying arsenic-containing creams to their faces in order to lighten the skin. So it wasn’t the only exposure in the environment. People were literally dosing themselves with arsenic.”
Arsenic in wine today
While phased out in vineyard use, it’s important to note that arsenic still occurs naturally in the earth. “As a naturally occurring element, it is not possible to remove arsenic entirely from the environment or food supply,” states the U.S. Food & Drug Administration. Mitigation is key.
The presence of arsenic in wine isn’t unheard of today, though it’s been a while since there was a headline grabbing poisoning incident. Instead, it’s more likely to be found in negligible quantities, if the wine is even tested at all.
Most of the time it isn’t.
“There were some lawsuits a few years ago,” says Waterhouse, referring to a 2015 California class action suit that alleged 28 wineries had created wines with dangerously high levels of inorganic arsenic. “Basically, they were saying that wine should have the same level of arsenic as tap water regulations, which isn’t really the case. People just don’t drink that much wine for it to build up in your system that way.”
The standard set by the EPA for safe levels of inorganic arsenic in drinking water is a maximum of 10 parts per billion (ppb). Presumably, that’s based on the recommendation that a person should be consuming around eight glasses of water each day.
“They were really just trying to shake down the industry,” Waterhouse says. Cobbold agrees, as did the court that dismissed the case a year later.
“I think the average content in the wine was 23 billion parts per billion,” she says. “The wine producers say it doesn’t matter if it’s a higher content than in water because people drink more water than they drink wine.”
But, if inorganic arsenic pesticides like lead arsenate and copper arsenate have been effectively banned for decades, why would there be any arsenic still detected in wine?
It’s likely absorbed from the soil by the vines. However, it’s unclear if it’s leftover from previous era’s pesticides and fertilizers, or if it naturally occurs in the soil.
“If soluble arsenic is present, it can be passively absorbed into plants,” says Nelson. “This thinking is affirmed by studies showing a correlation between the amount of arsenic in grapes and leaves, and that which is studied in soil and the amounts in grapes.”
Arsenic mostly accumulates in a grapevine’s root and leaf tissue, and “only a minimal amount of arsenic is relocating to the skin, pulp and seeds of the berries in grapevines,” she says.
In a 2019 paper, Nelson and her colleagues looked into how arsenic levels in wines change from harvest to fermentation and bottling. “We believe that the arsenic is adsorbing onto the yeast hulls, which then sink to the bottle of the barrel/container the wine is being made in, and is removed after fermentation,” she says.
She points to a study with similar findings that noted a 35% decrease in arsenic levels in rosé and red wines following fermentation. The increased levels prior to fermentation were attributed to the presence of grape skins. They believe that the decreased arsenic levels after fermentation was “due to the formation of a volatile arsenic species or biosorption by yeast hulls, which settle as sediment.”
Though Nelson believes that wine should continue to be monitored for its arsenic levels to better understand where they’re coming from, she agrees that a typical wine drinker likely couldn’t consume enough to experience toxic effects. To exceed the International Organisation of Vine and Wine’s limit of 200 micrograms of arsenic per liter, she says, you’d have to drink approximately 6.5 bottles of wine containing 30 micrograms per liter of inorganic arsenic in one day.
“For any typical consumer, this is an unrealistic expectation,” says Nelson.