The next generation of GM crops has arrived—and so has the controversy

By Brandon Keim, June 26, 2014. Source: Wired


Photo by Fishhawk/Flickr

Photo by Fishhawk/Flickr

The first of a new generation of genetically modified crops is poised to win government approval in the United States, igniting a controversy that may continue for years, and foreshadowing the future of genetically modified crops.

The agribusiness industry says the plants—soy and corn engineered to tolerate two herbicides, rather than one—are a safe, necessary tool to help farmers fight so-called superweeds. The U.S. Environmental Protection Agency and Department of Agriculture appear to agree.

However, many health and environmental groups say the crops represent yet another step on what they call a pesticide treadmill: an approach to farming that relies on ever-larger amounts of chemical use, threatening to create even more superweeds and flood America’s landscapes with potentially harmful compounds.

Public comments on the Environmental Protection Agency’s draft review of the crops will be accepted until June 30. As of now, both the EPA and USDA’s reviews favor approval. Their final decisions are expected later this summer.

“We’re at a crossroads here,” said Bill Freese, a science policy analyst at the Center for Food Safety, an advocacy group. “With these, we’re dramatically increasing farmer dependence on herbicides.” In a letter to the USDA, the Center and 143 other public-interest and environmental groups warned of a “chemical arms race with weeds,” in which the new crops offer “at best temporary relief.”

The crops under consideration were engineered by Dow AgroSciences, a Dow Chemical Company subsidiary. They’re part of what Dow calls the Enlist Weed Control System: Enlist, a proprietary mixture of glyphosate and 2,4-D herbicides, and the plants onto which Enlist can be sprayed without causing them harm as it kills surrounding weeds.

A similar approach to designing solely glyphosate-tolerant crops—Monsanto’s Roundup Ready trait—has made glyphosate the most widely-used herbicide in the United States. Those crops now account for more than 80 percent of U.S. corn and cotton, and 93 percent of all American soybeans.

When Roundup Ready crops were first introduced in the 1990s, some scientists warned that weeds would eventually evolve tolerance to glyphosate: After all, any herbicide-hardy weed would have an enormous reproductive advantage. Monsanto said that wouldn’t happen. It did, sooner rather than later. Such weeds are now an enormous problem, infesting roughly 75 million acres of fields, an area roughly equivalent to the size of Arizona.

Farmers have been sent scrambling for solutions, and products like Enlist and similar multiple herbicide-resistant crops developed by other companies are the agriculture industry’s solution. “Enlist Duo herbicide will help solve the tremendous weed control challenges growers are facing,” said Damon Palmer, the U.S. commercial leader for Enlist, in a press release accompanying the EPA’s draft announcement.

According to Dow, weed resistance can be forestalled this time around. But critics say it’s inevitable, and that applying 2,4-D at the anticipated landscape scales could harm both humans and the natural environment. The companies consider those fears to be overblown and based on a biased interpretation of the science. That is also what critics say of them.

If there’s any common ground, it’s this: If the Enlist system is approved, much more herbicide will be used in the United States. According to the USDA, somewhere between 78 and 176 million pounds of additional 2,4-D could be used on U.S. crops by 2020, up from 26 million in 2011.

Herbicides and Health

Among the galaxy of chemicals found in agriculture and everyday modern life, 2,4-D is comparatively well-researched. Scores of studies over the last several decades have looked for population-level patterns linking exposures to human health problems, or described the effects on animals experimentally exposed to 2,4-D.

Considerable disagreement exists, however, on how to interpret that research. Critics of the 2,4-D resistant crops emphasize the population-level epidemiology, which raises cause for concern. Dow and the EPA place much more weight on results from laboratory animal exposures, from which the effects of anticipated human exposures are extrapolated.

Based on the animal research, “we have looked at the possibility that Enlist could be used on every acre of corn and soybeans and concluded there would be no human health risk from such use,” the EPA said in a statement provided to WIRED.

Their evaluation fits with the state of the science as described by Dow toxicologist and former Society of Toxicology president James Bus, who said that even farm workers who handle 2,4-D on a daily basis are exposed to levels “that are 1,000-fold below doses which in animals cause no effect.”

“Almost all the key toxicology studies are in the peer-reviewed public literature. They’re not hidden in company files,” said Bus, who described the misgivings of Enlist’s critics as resulting from a lack of familiarity with the literature, or giving too much credence to findings of harm that involved unrealistically high doses or impure 2,4-D formulations.

In turn, the Environmental Working Group, an environmental advocacy group, said in a June 4 letter to the EPA that the agency’s health reviews were flawed, incomplete and “significantly underestimate the real harm to human health.”

Broadly speaking, health concerns fall into two categories: whether 2,4-d might cause cancer, and whether 2,4-D might disrupt the human endocrine system, perhaps causing reproductive or neurological damage. On a possible link to cancer, most research suggests otherwise: Both the EPA and World Health Organization’s International Agency for Cancer Research have previously declared that 2,4-D does not appear to be carcinogenic to humans.

A more recent review of the epidemiology by two WHO cancer researchers did find a significant link between 2,4-D exposures and non-Hodgkins lymphoma. Dow’s own review of the epidemiology, published in Critical Reviews in Toxicology, found no connection.

On the risk of endocrine disruption, however, the science is more ambiguous. The EPA acknowledged in a 2005 evaluation of 2,4-D that, based on experimental effects on animal thyroids and gonads, “there is concern regarding its endocrine disruption potential.” But Bus pointed to a recent Dow-run study of rat exposures that figured prominently in the EPA’s evaluation and was published last September in the journal Toxicological Sciences. In those experiments, damage arose only at exposure levels far higher than is found in real-world settings.

Some research has pointed in a different direction, though. In a 2012 letter to the EPA, a group of 70 public health scientists and health professionals cited several population-level epidemiological studies that linked 2,4-D exposures and birth defects in several midwestern states.

Epidemiology shows statistical correlations, not cause-and-effect, and is necessarily messy: It can be hard to isolate one chemical’s signal from a sea of variable factors. On the other hand, epidemiology deals with real-world dynamics, and for 2,4-D resonates with some experimental observations. In a 2008 Environmental Health article researchers wrote that “even though the evidence is sparse, some chlorophenoxy herbicides, in particular 2,4-D, have neurotoxic potentials and may cause developmental neurotoxicity.”

One of the study’s authors was environmental health professor Philippe Grandjean of the Harvard School of Public Health. Asked whether he still stood by that claim, Grandjean said that he does. “We know too little about the risks of developmental neurotoxicity” to dismiss concerns, he said.

A 2009 Archives of Neurology study also found suggestions of a link between 2,4-D exposures and Parkinson’s disease, though the number of cases was small. According to EPA, such reports will continue to be monitored as Enlist use is periodically reviewed, but may have resulted from older 2,4-D formulations that were contaminated by dioxin, an extremely toxic compound generated as a byproduct of 2,4-D manufacture.

Dioxin contamination is “no longer a factor in the modern manufacturing processes for 2,4-D,” said the EPA in its draft review. Again, critics are not reassured. “When you’re cooking it up, it’s inevitable that you’ll end up with dioxins being formed,” said Lynn Carroll, senior scientist at the nonprofit Endocrine Disruption Exchange.

A 2010 Environmental Science & Technology study by Australian toxicologists of dioxin contamination in 2,4-D found it to be an ongoing concern, though Enlist was not among the formulations evaluated. While buyers of Enlist seeds will be contractually obligated to use Dow’s reportedly cleaner formulations, Freese worries that farmers will evade those restrictions. “Based on general knowledge of enforcement of regulations in the field, it seems extremely likely that a lot of 2,4-D use will involve generic versions,” he said.

Environmental Impacts

In addition to possible human health impacts, many questions remain about the effects of 2,4-D on ecological health. In its statement to WIRED, the EPA said, “We are confident that there will be no off-site exposure to the choline salt of 2,4-D”—Dow’s new formulation—”that would be of concern for effects to plant or animals.”

But the agency’s own ecological risk assessment strikes a more uncertain tone: While stating that 2,4-D poses no direct poisoning threat to birds, fish, aquatic plants or insects, it noted a lack of empirical information about risks to mammals and terrestrial plants. “There is insufficient information to determine how the proposed new uses of 2,4-D choline salt will directly affect mammals … and terrestrial plants, and indirectly affect all taxonomic groups,” wrote the EPA’s ecologists.

That plants in areas adjacent to farm fields, or receiving soil-runoff water expected to contain 2,4-D, could be at risk seems self-evident: After all, 2,4-D is a herbicide, toxic to most plants that don’t have needles for leaves. “There are more and more concerns being raised about the drift problem,” said agroecologist Bruce Maxwell of Montana State University.

“These field edges are some of the last remaining harbors” of biodiversity in the midwestern United States, Maxwell said. They provide vital habitat and forage to many animals, in particular pollinators such as bees and butterflies, populations of which are in precipitous decline. The collapse of monarch butterflies has already been tied to the rise of glyphosate use.

The EPA’s draft review of Enlist, which emphasized the “practically non-toxic” direct effect of 2,4-D on bees, gave little weight to indirect effects, in part because the agency assumes farmers will use Enlist in ways that minimize its accidental spread beyond field edges. “If this product is used according to the label directions, no unreasonable adverse effects would result,” said the EPA in its statement.

It may be unreasonable, though, to expect farmers to always follow those directions, which include recommendations that Enlist not be sprayed closer than 30 feet to field edges, when wind is blowing above 2 and below 10 miles per hour, or when it’s too hot and dry. “Everyone knows these assumptions are unreal,” said Freese.

The Future of Superweeds

Such tensions between intentions and expediency are also evident in arguments over the potential for weeds to evolve in response to heavy 2,4-D and glyphosate use, just as they did in response to glyphosate alone.

According to Dow, this is unlikely, both because 2,4-D resistance is a relatively difficult trait for plants to acquire and because the company is committed to promoting growing practices—such as crop rotations and non-chemical weed control measures—that reduce selection pressures favoring herbicide-tolerant weeds.

Yet tolerance to 2,4-D has already been documented in several weed species that have elsewhere become glyphosate-resistant superweeds, including waterhemp and horseweed. Particularly troubling, said Maxwell, is the existence of mutations that confer broad-spectrum herbicide tolerance. These could spread through weed populations much more rapidly than constellations of several mutations, each conferring a piecemeal defense.

Weeds that can survive doses of multiple herbicides have already been found—not 2,4-D and glyphosate, at least not yet, but the potential is clearly there. “Stacking up tolerance traits may delay the appearance of resistant weeds, but probably not for long,” concluded a recent Nature editorial, which also argued that real-world practicalities may preclude good intentions.

“A farmer making good money in the age of biofuel crop subsidies may be loath to switch to a different crop,” wrote Nature‘s editors. “And farmers may be hesitant to invest the money needed to properly manage weeds, when their farms could end up infested with weeds from less-assiduous neighbours.”

Herbicide resistance expert Pat Tranel of the University of Illinois said that multiple herbicide-resistant crops like Enlist could be useful tools for farmers, “but we’re concerned that, as with any new tool, it will be overused.”

Ideally, said Tranel, “we’d be using herbicides as part of a system, and using other strategies such as crop rotation and more-diversified cropping.” Indeed, research by Tranel’s colleague Adam Davis has demonstrated the industrial-scale potential of such a balanced approach. But for now, said Tranel, “that’s not perceived as an economic alternative.”

The EPA’s draft assessment does not require farmers to rotate Enlist and non-Enlist crops. Instead, responsibility for slowing the rise of future superweeds is given largely to Dow. Farmers will be asked to scout their fields, reporting signs of Enlist-resistant weeds to Dow, which will investigate and decide whether to notify the EPA.

That raises obvious conflict-of-interest concerns, said Freese, citing as precedent Monsanto’s poor track record in monitoring the evolution of rootworm tolerance to genetically-engineered Bt corn. That was ultimately verified by independent academic researchers, not industry investigators. And even if Dow’s monitoring system is thorough, it may be insufficient.

“You can have the best surveillance system in the world, and the numbers are going to get you,” said Maxwell. “Resistance is going to be there. It will escape notice. And once it occurs at even a low, recognizable level, it’s going to continue to be there.”

Should that happen, the next logical step—at least from a commercial perspective—is to develop crops resistant to even more herbicides. Another of Dow’s soybean varieties, now being reviewed by the USDA, tolerates three herbicides; also in the regulatory pipeline are multiple herbicide-resistant crops from Monsanto and Syngenta, as well as crops that tolerate both herbicides and pesticides.

Freese pointed one of Dow’s patents, for a mechanism that would allow up to nine types of herbicide resistance to be engineered into a single plant. A patent claim is no guarantee that a technology will be used, but it may be an apt symbol for the near future of agricultural biotechnology.

“In the end, we’re going to render most of our chemical solutions obsolete,” said Maxwell. “In the meantime, unfortunately, we’re going to do some damage.”

Golden apple or forbidden fruit? Following the money on GMOs

By Nathanael Johnson, Grist

Much of the battle over transgenic crops has occurred in the realm of science fiction. There, entirely hypothetical health risks square off against visions of wondrous but imaginary benefits. This isn’t nearly as ridiculous as it sounds: To decide which technologies to pursue and which to avoid, modern Jules Vernes need to dream up best and worst-case scenarios.

The problem is, the debate tends to get stuck in the future. We’ve had transgenic plants for nearly two decades, which is enough time to fairly ask, who has actually benefited from genetically modified crops? We’ve had these plants long enough now that we don’t have to look to fantastic visions of the future; we can simply look at the reality.

In search of reality, I began emailing economists, lawyers, and advocates to ask them this question. The first to answer was Andrew Kimbrell, executive director of the Center for Food Safety. Kimbrell said the companies that bet on GM technology have been its greatest beneficiaries. “The chemical companies, right? The big five: Monsanto, DuPont, Dow, Bayer, and Syngenta … No. 2 would be farmers, specifically big farmers, because it makes their herbicide application a lot easier.”

Farmers pay more to buy the GM seed, and more for the herbicides to treat herbicide-resistant crops, but they save on labor costs. Rather than meticulously spritzing individual weeds by hand to avoid killing the crop, farmers can quickly spray an entire field when using herbicide-resistant plants, Kimbrell said.

Beneficiary No. 3? There is none, according to Kimbrell. “These companies have completely failed, in over 30 years, to come up with a trait that benefits a consumer. Nobody gets up in the morning wanting to buy a genetically engineered food.”

I could think of exceptions: Papaya genetically engineered to resist ringspot virus is more appealing to many consumers than diseased fruit. But these are exceptions that prove the rule; the vast majority of transgenic plants are designed to make farmers, rather than eaters, happy.

What about price? I asked Kimbrell. Do we eaters see lower prices because of genetic modification?

“No. There are no lower prices. GMOs have not lowered prices at all. They have massively increased prices for seed.”

Indeed, seed prices bumped up with the introduction of genetically modified varieties.

Seed Prices
Center for Food Safety
Data from USDA Economic Research Service.


What about GM crops lifting small farmers out of poverty? Kimbrell scoffed at that. “Smallholders can’t afford to buy [the herbicides] RoundUp and 2,4-D,” he said.

Ask people on opposite sides of this issue if genetic modification benefits the poor and you’ll hear wildly different claims. Kimbrell’s point is that GM crops are designed to save farmers time and money if they are involved in high-tech agriculture. Vandana Shiva, an environmental activist and longtime critic of industrial agriculture, has pointed to cases in which small farmers in India have killed themselves when the debt they’ve taken on to buy seed, fertilizer, and pesticides grows too crushing.

On the other hand, biotech industry consultant Clive James maintains that GM crops are a ladder to prosperity. James has calculated that in 2012, for the first time, farmers in the developing world planted more GM seed than farmers in industrialized nations. These farmers must have a reason for seeking out transgenics.

Transgenics in developing countries
Clive James


As usual in this debate, I find myself stranded between irreconcilable claims. But fortunately, it turns out there’s a large body of economic analyses that have asked precisely the same question I have: Who has benefited?

One of the people I’d emailed, UC Berkeley agricultural economist David Zilberman, sent me a short note from the Ivory Coast suggesting that the benefits of GE food are widespread:

“The seed companies captured less than 50 percent of the economic gains in most studies (frequently less than 30 percent),” he wrote. “The rest [is] distributed between farmers and consumers.”

The studies Zilberman consulted on this question have found that the biotech industry captures between 10 and 70 percent of the money generated by their transgenic seeds. The rest of the benefit (30 to 90 percent) is shared by U.S. farmers, U.S. eaters, and the rest of the world. That’s a huge range, but it’s interesting that every study examining this issue has found that consumers do benefit from food prices. It may not be much — less than 2 percent is the estimate at the lower end — but the average Joe and Jane are probably getting some extra change thanks to GMOs.

OK. Now, what do the economists say about small farmers? Are GM crops lifting them out of poverty or driving them to suicide? A review of the economic publications on this question found that:

During the first decade of their use by smallholder farmers in developing economies, peer-reviewed research has indicated that, on average, transgenic crops do provide economic advantages for adopting farmers.

Makhathini Flats
Makhathini Flats.


But hold on: That average hides all sorts of highs and lows. I love this review, done by the International Food Policy Research Institute, because the authors carefully noted the problems with each analysis. For instance one study, following the introduction of GM cotton to the Makhathini Flats in South Africa, found that small farmers were major beneficiaries of the technology. But another, more thorough, analysis suggested something more complex: Small farmers had made a little more money with the transgenic cotton, but only because the Vunisa Cotton company had set them up for success.

Vunisa pitched the transgenic seed to farmers; supplied them with pesticides, fertilizer, loans, and advisors; and then bought up all their cotton. Farmers are vulnerable when they can only buy from, and sell to, one company. That company can ratchet up the cost of seed, while ratcheting down the amount it pays for cotton. So in the Makhathini Flats, farmers were making a little more money — at least for the first few years — but they were also in a much more precarious position.

And this example is part of a theme. In general, GM crops do seem to give small farmers an economic boost, but the studies rarely look at the bigger political and economic tradeoffs those farmers are making. Those tradeoffs do sometimes have dire consequences — like farmer suicide.

But it doesn’t look like the introduction of GM crops is responsible for a large percentage of those deaths. Check out this graph from Nature:

Farmer Suicides

The sad fact is that a lot of farmers kill themselves in India. The numbers didn’t budge significantly with the introduction of GM plants. There are, however, many well-documented cases in which debt — in part from the purchase of GM seeds — drove farmers to suicide. That’s absolutely true. It’s more accurate to say that suicides are caused by the bigger economic monster: The system that requires farmers to take on extravagant debt to compete.

A small farmer who owns his land and saves his seeds each year is relatively independent. A farmer who must take out loans to buy GM seeds, fertilizer, irrigation equipment, and pesticides is beholden and making a riskier (though also potentially more lucrative) bet. For each technological innovation, farmers trade some of their independence for a shot at greater profit. Perhaps it’s fair to say GM seeds are a synecdoche — a part that represents the whole — for the larger system that’s causing farmer suicide in India, especially in those areas where the only seed available to farmers is genetically modified.

So who has made money from GM technology? Seed and chemical companies, for sure. Big farmers, too. Little farmers have gained less, and have had to trade away more privileges. And the rest of us probably pay a little less for GMO food (industrial meat, for example). And all of this is a little fuzzy, because economics is an inexact science, and the studies are still coming in.

The question of who benefits goes beyond money, of course. We also need to look at the environment: Some see GM crops as an environmental savior, while other say they are a disaster. I’m going to make my usual kamikaze run into this minefield to see if there’s any way to reconcile the evidence each side presents.

Before I do that, though, I’m going to talk to some farmers and learn what the pluses and minuses look like from their perspective. Do farmers feel they are trading away intangibles for each new technological advancement?

More in this series:

Nathanael Johnson (@savortooth on Twitter) is Grist’s food writer and the author of All Natural: A Skeptic’s Quest to Discover If the Natural Approach to Diet, Childbirth, Healing, and the Environment Really Keeps Us Healthier and Happier.