Experts call on feds to re-evaluate the world’s most heavily used herbicide
Health scientists—in a review of the published data on glyphosate—see a “desperate need” for federal regulators around the world to revisit the herbicide's health impact
February 17, 2016
By Brian Bienkowski
Environmental Health News
U.S. and European health officials need to take a fresh look at assumptions about the safety and health impacts of glyphosate herbicides, according to a group of health scientists worried about the chemicals’ explosive worldwide growth.
A scientific review released Tuesday warns that use of glyphosate has skyrocketed, growing 15-fold in the 20 years since "Roundup Ready" genetically engineered crops were introduced. Government health agencies, they said, have failed to adequately monitor how much of the herbicide is getting into food and people and what impacts it might be having on our health.
|Senior author of the new report, Charles Benbrook. (Credit: jhsph.edu)|
“It’s time to call on the global science and regulatory community to step back and take a fresh look at glyphosate since everyone on the planet is or will be exposed,” said senior author Charles Benbrook, an agricultural economist and consultant at Benbrook Consulting Services.
Use of glyphosate in herbicides has increased exponentially since it was first used in the 1970s, according to the review. The study, published in the journal Environmental Health, was authored by 14 health scientists mostly from universities. Pete Myers, founder and chief scientist at Environmental Health Sciences, publisher of EHN.org, was the lead author of the report.
Glyphosate, known most famously as Roundup but also sold under a variety of brand names, is the most heavily used farm chemical in the history of the world. Across the globe roughly 9.4 million tons of the chemical have been sprayed on fields since 1974. Nearly 75 percent of that use has come in the last 10 years, according to a separate report Benbrook issued earlier this month.
That growth, said scientists reviewing the data, means government benchmarks and safety levels are out of step with the reality of exposure risk—for both the public and the environment.
Federal health agencies—such as the U.S. National Toxicology Program, the U.S. Centers for Disease Control and Prevention and the German Federal Institute for Risk Assessment—simply haven’t kept up, according to the report.
“Since the late 1980s, only a few studies relevant to identifying and quantifying human health risks have been submitted to the U.S. EPA,” the authors wrote, adding that such assessments need to be based in “up-to-date science.”
Glyphosate—a key ingredient in many weed-killer herbicides—works largely by inhibiting a plant enzyme that doesn’t exist in mammals, so it was initially thought the chemical posed little risk to humans and other vertebrates.
However, evidence has been mounting that exposure to glyphosate may not be so innocuous. The U.S. Department of Agriculture in 2011 found glyphosate in 90 percent of 300 soybean samples, and the UK Food Standard Agency found it in 27 out of 109 bread samples in 2012.
It’s been linked to liver and kidney problems, birth defects, and it potentially disrupts the proper functioning of hormones. In recent years, scientists have increasingly suspected it might be at least partially behind a widespread kidney disease epidemic in Sri Lanka and parts of India and Central America.
Last year the World Health Organization’s International Agency for Research on Cancer in March changed glyphosate’s status from a “possible” to “probable” human carcinogen.
One of the main gaps identified in the report is the lack of endocrine disruption testing, said Frederick vom Saal, University of Missouri biologist and co author of the report. There is increasing evidence that glyphosate may impact human hormones, which can spur numerous later health impacts.
Standard federal testing is mostly done by dosing lab animals with high amounts of a chemical, and then looking for obvious impacts such as changes to organ weights and other malformations, said vom Saal. “Very little is done in the way of looking at developmental issues.”
The studies done in the 1970s when glyphosate was approved were “very unsophisticated,” Benbrook said. “The problem with dose ranges that are very high is [that] research on developmental problems and endocrine disruption has shown repeatedly chemicals can have subtle effects at much lower levels,” he said.
The U.S. Environmental Protection Agency (EPA) concluded in a report last June that there was “no convincing evidence” that glyphosate is an endocrine disruptor.
EPA spokesman Robert Daguillard said the agency will review the new report and added that they are finishing up preliminary human health and ecological risk assessments, which are expected to be published for public comment in 2016.
The health concerns coincide with more and more use and pervasive exposure. Over the past decade glyphosate has been bundled up in the debate over genetically modified food, because many seeds from companies such as Monsanto—manufacturer of the most popular glyphosate herbicide, Roundup—are genetically engineered to withstand the herbicide.
When crops such as corn and soybeans have such immunity, farmers can spray entire fields. This has spurred a vicious cycle where weeds are increasingly evolving resistance to the herbicides, leading to more and more spraying.
“The geographic scope and severity of the weed control challenges posed, worldwide, by the emergence and spread of glyphosate-resistant weeds is unprecedented,” the authors wrote.
Glyphosate herbicides have proved controversial and have been under the gun lately. Last week 35 House Democrats wrote a letter to the EPA urging the agency to reassess the risks of Dow Chemical Co.’s glyphosate herbicide Enlist Duo given the WHO’s cancer findings.
“EPA registered Enlist Duo without considering this cancer finding, and without looking at any studies on glyphosate’s cancer risk that have been published in the last twenty years,” wrote the lawmakers, led by Reps. Earl Blumenauer and Peter DeFazio.
Dow Chemical Co. did not respond to a request for comment on the new review. Monsanto spokesperson Charla Marie Lord said in an emailed response that the report's concerns were not in line with what regulatory agencies have found.
"No regulatory agency in the world considers glyphosate to be a carcinogen," she said. "Regulatory agencies have not had any health concerns that would necessitate testing of the sort proposed by the authors of this essay."
The company in January filed a lawsuit against California’s Office of Environmental Health Hazard Assessment designed to prevent glyphosate from being added to the state’s list of known carcinogens.
It’s not clear what kind of impact a statement from a group of scientists can have on federal policy. But vom Saal said that even if the EPA does not alter testing, it could spur more progressive states such as California to take action.
Benbrook said a modern test, conducted by independent scientists, is long overdue.
“I hope they don’t show anything and we can move on,” Benbrook said. “But if there’s even a small chance of health impacts, when you’re talking about everyone on the planet, that should cause us to use some caution.”
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