GMOs and Pesticides—What Concerns Scientists
01 Sep, 2011
by Bruce Boyers,
Genetically modified organisms (GMOs) began being released in the early 1990s, with big promises. The idea put forward was that certain traits, including increased nutrition, resistance to drought and faster growth, could be bred into crops such as corn and soybeans so that improved produce could be grown in much higher yields.
Genetically engineered crops have been with us now for some 20 years, and it is becoming apparent that the reality of GMOs has fallen far short of business model expectations. A report issued in 2009 by the Union of Concerned Scientists entitled Failure to Yield: Evaluating the Performance of Genetically Engineered Crops found that GM technology has not increased yields at all through its entire history, despite the millions that have been spent on GM development, much of it from government funding.
The public is becoming increasingly concerned about GMOs, as scientific evidence is arguing against the safety of public consumption and the widespread growing of GMO crops. Of greatest concern, however, is new research regarding pesticides developed strictly for GMOs, which may prove to be the tipping point for the entire technology.
One trait that has been successfully bred into GMO crops is resistance to pesticides. When a trait is bred into a crop making it resistant to one particular herbicide, that herbicide can be used with impunity against weeds while not affecting the primary crop. This of course only works when farmers who plant these crops use that specific herbicide.
The vast majority of commodity crops—including corn, soybeans, canola, cotton and now alfalfa—have been bred to resist one best-selling herbicide called glyphosate. Glyphosate is what is known as a broad-spectrum herbicide, meaning it is designed to kill a wide variety of weeds. Glyphosate is the primary active ingredient in the extensively used Roundup herbicide, and up until the year 2000 Roundup’s manufacturer—Monsanto—had proprietary rights to the compound. Since that time, Monsanto has continued to use it, but now generic glyphosate has appeared from a number of other manufacturers, and even from China.
Because of the quantity of GMO crops designed to resist glyphosate, an unnerving amount of this chemical is being employed. “The EPA recently came out with an estimate of glyphosate use,” Bill Freese, Science Policy Analyst with the Center for Food Safety, told Organic Connections. “It is for the year 2007, so it’s actually probably even higher now; but they’re estimating that in agriculture in the US, 180 to 185 million pounds of glyphosate are used yearly. It’s a huge quantity, and it’s coming close to half of all herbicides in use. If you include other applications like home and garden, commercial and industrial government use, it’s up right around 200 million pounds. It’s probably the most widely used pesticide in history.”
As one might imagine, such a sheer volume of poison being applied to millions of acres of farmland might begin to manifest negative effects—and credible scientists are telling us this is the case.
Effects on Plant, Soil, Animal and Human Biology
Glyphosate does not function as a normal pesticide might, directly killing the plant with which it comes in contact. Its action is actually far subtler: it acts as a chelating agent, whereby it binds itself to molecules, such as minerals, and holds them tightly, making them unavailable to the plant or weed.
In fact, glyphosate was originally patented as a chelating agent and quite accidentally became an herbicide. “Glyphosate belongs to the chemical family of phosphonates, which is a family of chelating agents,” Dr. Arden Andersen, soil scientist, agricultural consultant and physician, explained to Organic Connections. “Glyphosate was originally patented by Stauffer Chemicals in the early 1960s as a descaling agent [used to remove mineral residues inside dishwashers, vents and the like]. It was only by serendipity that it got spilled, or something, and it killed the weeds it contacted. It was subsequently purchased by Monsanto, and the rest is history. The key needed understanding to have is that glyphosate is a broad-spectrum chelating agent and was originally designed and patented as such. Its effect and use as an herbicide have been afterthoughts.”
This chelating action actually leads to harm for plants, as it removes important trace minerals, a fact observed by Dr. Robert Kremer, microbiologist with the USDA Agricultural Research Service, who conducted a 15-year study on glyphosate’s effects on plants and root microbiology. Dr. Kremer is also an adjunct professor in the Division of Plant Sciences at the University of Missouri, where he teaches environmental soil microbiology and advanced weed science. “Glyphosate is a chelator, which will bind with elements such as manganese and calcium, and those sorts of nutrients, and immobilize them,” Dr. Kremer told Organic Connections. “In other words, it will make them unavailable for plant uptake.
“As we have studied the microorganisms in root systems over time, we have seen a shift toward more colonization of the roots with some particular fungi that could, under certain circumstances, be a detriment to crop growth,” Dr. Kremer continued. “We also did a small side study in which we demonstrated that the glyphosate molecule is being transported to the roots and released into the soil around the roots. There is a possibility that this chemical being released through the root system interacts with certain microorganisms and maybe selects these at the expense of other microorganisms there that might be beneficial to the plant.”
Dr. Don Huber, professor emeritus at Purdue University, is a highly respected 55-year veteran microbiologist and plant pathologist. He too has been carefully researching this issue and has paid special attention to glyphosate’s effects on the trace mineral manganese. “Manganese is an essential micronutrient for photosynthesis and carbohydrate metabolism, as well as for plant defense mechanisms to a series of soil-borne pathogens,” Dr. Huber briefed Organic Connections. “It’s also important in defending against stress such as drought and even excess water. In researching the impact of glyphosate on manganese availability, it became very apparent that the chelating activity of glyphosate had a direct effect on manganese availability for uptake, in addition to being very toxic to the organisms that are responsible for making manganese available to the plant and the soil we started with. There are several mechanisms involved with glyphosate that we generally don’t see with most of the other herbicides, and the research led us to recognize why we’re noticing a general increase in a lot of plant diseases that we used to manage fairly well.”
But glyphosate’s fostering of pathogen growth may not only be harmful to plants. In fact, there is recent research suggesting strong evidence that this characteristic could affect animals fed GMO corn and soybean feed—and might potentially affect humans as well.
“Veterinarians have been reporting a new, as-yet-unnamed organism that is related to reproductive failure,” Dr. Huber said. “They have identified genetically modified plants as the source—especially soybeans and corn. They’ve established this new organism as the cause of that reproductive failure—infertility, miscarriage and spontaneous abortions. The plant has been tied, as the source, to those situations where you see conditions favorable for this organism to proliferate. We don’t have the research to document a direct effect of glyphosate in increasing that pathogen, but the evidence is that it changes the environment to make the plant more conducive for that organism to proliferate, and to thus be available and in the grain and feed that the animals receive.”
What are the chances that this pathogen could transmit to humans? “It has been found in animal tissues and in products that would be consumed by humans,” Dr. Huber remarked. “This organism infects a broad scope of animals already—horses, cattle, pigs, sheep, goats and poultry. To believe that it wouldn’t infect humans would be kind of naive at this point, I think. There’s a lot of research that needs to be done, but it would certainly not be out of the ordinary to recognize that there’s also a potential safety aspect as far as humans are involved.”
Several months ago, prior to the USDA approving GMO alfalfa for planting, Dr. Huber wrote a private letter to Secretary of Agriculture Tom Vilsack urging him to study these findings before the approval of yet another glyphosate-resistant crop. “I wrote the letter to bring to Secretary Vilsack’s attention the concerns a number of us have, and to solicit his assistance and resources in getting the information that we really need to thoroughly understand the epidemiology* of this organism. It was written with the hope that it would be forwarded—which it was—to those groups within the USDA who would be responsible for responding to that information, and with the possibility that there might be some resources allocated for really looking at all of the features of glyphosate, GMO organisms and this new organism as they impacted our overall crop and animal production system.”
Despite his letter and submission of follow-up peer-reviewed scientific data, Dr. Huber has, as yet, been unsuccessful in efforts urging the USDA to conduct broad and definitive studies on this pathogen, its causes and its potential harmful effects. “Dr. Huber has raised some really serious concerns about potential impacts of glyphosate on plant and animal health,” Bill Freese, Science Policy Analyst with the Center for Food Safety, stated. “The USDA should seriously research this issue as more data is accumulated.”
Increasing Weed Resistance
As with any pesticide, increased use of the agent causes resistance in the pests to which it is being applied. “The glyphosate-resistant weed issue is reaching a really serious stage,” said Freese. “One Iowa weed scientist was telling me that people are expecting these weeds to explode in Iowa in the next year or two. They’re creeping from the East and the South into the Midwest and people are starting to see them somewhat in the North. Studies out there are already showing that weeds are going to evolve resistance to this and other herbicides too. So probably we’ll have weed populations resistant to multiple herbicides—kind of like an arms race between the crops and the weeds. They engineer a new resistance into a crop, and then you use tons of that herbicide and the weeds develop resistance to the herbicide. It’s totally unsustainable agriculture, bad for the environment and human health, and it’s where this Roundup Ready model is leading.”
The Battle Continues
As Dr. Huber points out, issues such as the newly discovered pathogen fostered by glyphosate can have far-reaching effects. “This organism could have a tremendously negative impact on our exports,” Dr. Huber said. “The organism has been detected in our exported soybean products, and reproductive failure of increasing severity is also being reported in other countries.”
Because of the lack of long-term studies and conclusive science showing these biotech creations to be safe for human consumption, alarmed consumers are increasingly speaking out against GMOs and expressing their desire to not have GMO foods available in the marketplace, especially unlabeled. Natural products retailers are taking note—and some, such as Mile High Organics of Colorado, have gone all out to ensure that the products they sell are 100 percent GMO free.
“I don’t believe that consumers should be deceived,” Michael Joseph, founder and CEO of Mile High Organics, told Organic Connections. “I don’t consider that the US government is doing a good job of protecting its citizenry, and some retailers are starting to step up and have done very well at educating their consumers. We really have found a strong and loyal consumer base that believes exactly the same thing, and people have thanked us. I’ve had people tell me that they think I’m essentially doing work that should be done by the government.”
Equally vocal are food activists and natural food advocates such as best-selling writer and educator Anna Lappé, author of Diet for a Hot Planet: The Climate Crisis at the End of Your Fork and What You Can Do about It. “Our regulators have allowed genetically modified foods to enter into our food system without taking seriously the concerns, not only about public and animal health, but also about the impact of GMOs on biodiversity, on pest and weed resistance, and other negative externalities—as economists would say—that should have been red flags about this technology from the beginning,” Lappé told Organic Connections.
“The real underlying issue is that we don’t even need this technology,” Dr. Arden Andersen concluded. “We already have the wherewithal, the science, the technology and the products to solve every problem that has been proposed to need genetic engineering technology. So when you think about it, if we already have the technology to solve all of those problems, why are certain people wanting to pursue genetic engineering? It is certainly not from a need perspective; it’s not from a science perspective—it’s strictly for want of monopolization and greed. That’s it.”
*epidemiology: the study of the incidence, transmission and containment of epidemic disease.