Without a doubt, glyphosate is currently the
one most raised and controversial active ingredients around the globe. This
should come as no surprise, considering that it is the herbicide most used
around the planet. Monsanto patented the molecule named Glyphosate (N-(phosphonomethyl)glycine, C3H8NO5P,
CAS 1071-83-6) in the 1970s, and started marketing it worldwide in 1974 with
the name Roundup®. Its patent expired in the year 2000, and today one can find
a large number of products on the market whose formulations include this active
ingredient. Glyphosate?s principal use is as a broad-spectrum herbicide for
eliminating weeds and shrubs but this is not its only application; it is also
used, for example, as a sugarcane ripener.
The consequences for human health and
environmental impact caused by glyphosate have been the subject of major
debate. But how much glyphosate is actually applied? According to a study
published in 2016 by the journal Environmental Sciences Europe, since its
introduction 1.8 million tons have been applied in the United States and 9.4
million tons worldwide. For comparison, that is equivalent to the amount of
water in 2,300 Olympic-sized swimming pools. Up until the 1990s, its
application was more or less controlled, but Monsanto?s launching of
genetically modified varieties of glyphosate-resistant soy beans and corn made
its use grow exponentially. For example, in the USA, 5.5 million liters were
applied in 1987; at present some 150 million liters are applied each year. In
countries such as Colombia or Peru, glyphosate has also been used in massive
quantities to eradicate cannabis plantations. Another factor contributing to
its increase is its residential use in gardens as of the mid 1990s.
Use Permits
The European Commission renewed glyphosate?s
use permit in June of last year for 18 months, which means that it will remain
authorized until December 31, 2017, or until 4 months from now. At that point,
the commission will have to decide whether to extend the authorization further.
In March of this year, the European Chemicals Agency (ECHA) reported that it
had not found scientific evidence that glyphosate is a carcinogen or can cause
significant problems for human health. This runs counter to the opinion of the World
Health Organization (WHO), whose International Agency for Research on Cancer
classified this product as ?probably carcinogenic.? Other studies have also
indicated that glyphosate can have repercussions as an endocrine disruptor by
interfering with the correct functionality of certain hormones. What does
Monsanto say? Actually, for years it has been maintaining that ?Glyphosate
safety is supported by one of the most extensive human health, crop residue and
environmental databases ever compiled on a pesticide product,? as a company
spokes person recently stated. As that data base is not currently public, we
were unable to corroborate that assertion.
In the United States, the EPA categorizes
glyphosate as a product that is ?slightly toxic? for humans and birds and ?practically
nontoxic to fish, aquatic invertebrates and honeybees.? Currently, glyphosate
is undergoing a reevaluation, together with other active ingredients. The EPA?s
classification was made by solely studying possible carcinogenic levels and not
alterations of the endocrine system.
Despite this EPA classification at the federal
level, the State of California, based on a recommendation from the California
EPA, has listed glyphosate as a carcinogen under Prop65, the Safe Drinking
Water and Toxic Enforcement Act of 1986. The law is intended to ensure that the
water supply is not contaminated with chemicals that the State of California
recognizes as causing cancer, birth defects or other reproductive harm. In
addition, Prop 65 requires companies to provide a warning to anyone who would
be exposed to those chemicals during the company?s activities.
Permitted Limits
Like all regulated pesticides, glyphosate is
subject to maximum residue limits (MRL?s). In the United States these limits
range from 0.1 mg/kg in certain seeds to 0.2 mg/kg in most fruits
(strawberries, avocados, apples, grapes, etc.) and up to 20 or 30 mg/kg in
certain grains. In the European Union the MRL?s are similar, although some
fruits such a stable grapes have a higher tolerance (up to 0.5 mg/kg).
Considering that many pesticides are subject to a limit of 0.01 mg/kg, it can
be stated that the limit for glyphosate established by the various legislations
is quite a bit higher than that of many other active ingredients. This does not
necessarily mean that the limit for this herbicide is more permissive than that
of other compounds. Indeed, one would suppose that this variance is the result
of toxicological and ecotoxicological impact studies, and it should be
considered that there are pesticides with limits of up to 20 or 30 parts by
million. In the end, the harmful effect of a pesticide will depend on its toxic
properties and on the dose at which it is applied. In the words of the famous
Swiss alchemist and physician Paracelso, ?everything is poison and nothing is
poison, the difference lies in the dose.?
Environmental Impact
Besides glyphosate?s possible effect on human
health, it has an environmental impact to soil and water. In soils, this
compound?s degradation depends upon the environment; it could be biotic
(microbial) or abiotic (photo degradation or chemical degradation). The period
of degradation ranges from 50 to 280 days, depending upon temperature and the
pH of the soil. In soils with intense microbial and microfauna activity it has
also been proven to degrade in a few days. Nonetheless, the metabolite of
glyphosate (AMPA) can persist for up to 950 days. Information regarding the
movement and persistence of glyphosate in soils is highly varied. According to
the EPA, when glyphosate reaches the soil it is strongly adsorbed, even in
soils with a low content of clay and organic matter. So even though glyphosate
is highly soluble in water, it is considered to be immobile or almost immobile;
it remains in the upper layers of the soil with little probability of
percolation and low potential for runoff.
With respect to its impact in water, glyphosate
can reach the aquatic ecosystem by accidental overspray, drift or surface runoff.
Glyphosate has high solubility in water (12 grams/liter at 25º C), yet its
persistence appears to be less in water than in soils. All studies conducted
agree that this persistence ranges from 12 to 60 days. Nonetheless, it is quite
easy to find water sources with levels in excess of what is established in the
various legislations. Here again, there are variations. For example, in USA the
limits 0.7 parts per million, while in Canada it is 0.28 and in Spain 0.01. It
is easy to see that the differences are extremely significant.
Lastly, it should be mentioned that numerous
studies are being conducted around the world on glyphosate?s possible effect on
populations of butterflies and bees. Other lines of active research are also
underway, such as correlations with gluten sensitivity.
Laboratory Results
AGQ Labs has been
analyzing the active ingredient glyphosate for years, both in foods and in drinking
water. The technique utilized is Liquid Chromatography Tandem-Mass Spectrometry
(LC-MS-MS), which is unquestionably today?s state-of-the-art instrumentation for
this type of analysis.
A study conducted over the past two years
revealed the following results: in foods, in the United States, 40% of the
samples analyzed tested positive for Glyphosate, but only 1.18% surpassed the
limit set by U.S. law. In Europe, of the thousands of samples analyzed in our
laboratory in Spain, 15% have tested positive, but only 1.87% exceeded the
limits set by European law.
As one can see, though we have observed more
positive results in our US testing, the percentage of samples surpassing the
limit legal was very similar to our testing in Europe. The product for which
the highest concentrations of glyphosate have been found is honey.
In the case of water, only 7.7% of the samples
analyzed in Spain tested positive.
In summary, rigorous scientific studies need to
continue being conducted regarding the product?s actual danger. Yet given the
low percentage of samples whose residues of glyphosate exceed the established
limits, we can conclude that its application in the field is in keeping with
the recommendations for the dose to be applied, and that as a general rule the
safety precautions as established by regulatory agencies are being respected.
It should be clarified that most of the food
samples analyzed by AGQ Labs are fruits and fresh vegetables. We know for a
fact that in samples of grains (wheat, corn, soy beans, etc.) and sugar cane, the
presence of glyphosate is much greater, given its massive use on those crops,
especially in their genetically modified analog.
