Glyphosate Toxicity, Cause of Disease: Science Used to Regulate Monsanto Roundup Herbicide is Outdated: Study
Environmental health scientists call for expanded research and monitoring of world’s most widely used herbicide
Glyphosate, the active ingredient in
Monsanto’s Roundup herbicide, is now the world’s most widely used
weed-killer. First sold to farmers in 1974, its use has increased
approximately 100-fold since. Nearly all the corn and soy grown in the
United States is now glyphosate-tolerant and
treated with the herbicide. The weed-killer is also used on numerous
other food crops and on landscaping plants. Enough glyphosate is now
used to cover nearly every acre of cultivated cropland in the US. The chemical has been found in streams, wastewater, and in rainwater samples taken from all across the country.
Despite the extensive and increasing use
of glyphosate, we know little about how much of the chemical people are
actually being exposed to. Here in the US, glyphosate is not among the pesticide residues
for which the US Department of Agriculture (USDA) routinely tests food.
It is also not included among the 200-plus chemicals on the US Centers for Disease Control and Prevention’s (CDC) human biomonitoring program.
Photo by Rob Franksdad Recent science also suggests that glyphosate lasts longer in soil and water than originally anticipated.
In a paper just published in the journal Environmental Health,
14 leading environmental health researchers say current safety
standards are based on outdated science and inadequate exposure data and
that new research into glyphosate’s toxicity should be a government priority.
“When these chemicals are approved for
safety it’s based on assumptions of how they’ll be used,” including “at
what time of year and at what quantities,” explains paper co-author
Laura Vandenberg, assistant professor of environmental health sciences
at the University of Massachusetts, Amherst. “Even if this was a
completely benign chemical, it’s shocking to know how much its use has
increased,” she says.
Vandenberg and her co-authors point out
that to accommodate changes in use, the levels of glyphosate-based
herbicides allowed in crops — that include corn, soybeans, canola, and
various livestock feeds have been increased. But they also point out that estimates of safe daily limits for eating
food that might contain glyphosate – both in the US and in Europe – are
based on science that does not reflect how much the chemical is now
used. Recent science also suggests that glyphosate lasts longer in soil and water than originally anticipated.
In addition to using glyphosate at
planting time, farmers are now using it just before harvest, to dry
leaves in order to make the physical harvesting of plants easier. “Late
season, harvest aid use of GBHs [glyphosate-based herbicides] is an
important new contributor to the increase in residue frequency and
levels in some grain-based food products,” the researchers write. Such
use was not accounted for when safety limits were set for glyphosate
when the herbicide was introduced. In recent testing done in the United Kingdom, glyphosate residues were found in about one-third of bread samples tested. And in the US, testing by the USDA in 2011 found glyphosate in about 90 percent of soybeans
tested. But the paper points out that since such tests aren’t conducted
regularly, there is no information about what people are exposed to
through food on an ongoing basis.
In addition, there isn’t any continuous
data on human exposure. “Glyphosate is being used way more than anyone
ever anticipated and there is no biomonitoring data,” says report
co-author Bruce Blumberg, professor of cell biology and biomedical
engineering at the University of California, Irvine.
Health concerns
Adding to concerns about glyphosate is
the fact that last year, the World Health Organization’s International
Agency for Research on Cancer concluded that glyphosate is “probably carcinogenic to humans.” Glyphosate product manufacturers, including Monsanto, dispute this conclusion.
The chemical also presents other health
concerns. Among those, the paper notes, are adverse effects on the liver
and kidneys. There is also the possibility that glyphosate may impact
the function of certain hormones — impacts that could influence a number
of body systems, and influence development of chronic diseases. The
researchers also point out that we know little about the effect of
glyphosate-based herbicides on the immune and neurological systems –
information that would be key to understanding potentially profound but
subtle health impacts.
“We don’t know a lot but what we do know suggests harm,” says Blumberg.
“Glyphosate,” explains Vandenberg, “is
not an overtly toxic chemical, which in part is why glyphosate use has
soared.” But she says, “Glyphosate may contribute to more subtle
diseases.”
Research on glyphosate’s toxicity, the
paper explains, has typically focused on how much of the chemical will
kill a lab animal — not to investigate what happens at low and chronic
levels of exposure via food or drinking water. Vandenberg also explains
that in addition to understanding how glyphosate itself acts on humans
and the environment, it is important to understand the behavior of its
primary chemical breakdown compound. That, she says, is yet another data
gap.
Yet another concern is that
glyphosate-based herbicides are often applied in conjunction with other
pesticides and little is known about the effects of these mixtures.
Safety levels for pesticides are calculated for each active ingredient
individually, despite the fact that in most agricultural operations, a
cocktail of them are applied together. Combinations of glyphosate plus
other herbicides are now common in agriculture given that many weeds have developed glyphosate resistance from years of overuse.
Closing the data gaps
To close the many gaps in what is known
about glyphosate exposure and toxicity, the researchers call for both
new research into glyphosate’s biological activity and epidemiological
studies. They recommend that the CDC include glyphosate in its
biomonitoring program and that the US National Toxicology Program make
glyphosate a research priority.
“The main point we were trying to make
is that use has gone up and there is a lot of uncertainty about health
effects,” says Blumberg.
Given that glyphosate is showing up
widely in the environment – something not expected when the herbicide
was first approved – and that its use has increased so dramatically
since initial safety assessments were made, and what has been learned
about its health effects since, suggest that a reevaluation is
imperative, the researchers write.
“The big take away,” says Vandenberg,
“is don’t throw yours hands up in fear, but that something we’ve been
told is safe hasn’t been tested in the way that we can draw that
conclusion from.”
The original source of this article is Earth is Land
Copyright © Elizabeth Grossman, Earth is Land, 2016
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