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 Glyphosate - brought into use by Monsanto in the 1970s and used in
its top-selling product Roundup - is "unlikely" to cause cancer
according to the European Food Safety Authority (EFSA), yet
"probably" does, according to the International Agency for Research
on Cancer (IARC).
Both are likely to be right, specialists say, but only in their own
contexts. And for consumers, the key distinction to understand is
the difference between hazard and risk.
"At face value the opinions of IARC and EFSA appear to be contrary,
but the reality is they are not directly comparable," said Peter
Jenkinson, a genotoxicologist and managing director France & UK of
the chemicals consultancy CEHTRA Ltd.
That's partly because the evidence the two agencies considered was
not the same - EFSA only assessed glyphosate, while IARC looked at
glyphosate alone and at products it's used in - and partly because
they used different methods to draw conclusions.
Just as importantly, however, it is because they approach their task
from different stances - one being hazard identification, the other
being risk assessment.
Jenkinson noted that while EFSA used a "weight of evidence" approach
in its review, published last week, IARC, which issued its
glyphosate classification in March, takes the view that if one study
has a positive result it can outweigh negative studies, even if
there are more negative than positive ones.
EFSA also analyzed some studies conducted by industry groups that
were not part of IARC's review. IARC says it looks solely at
evidence that has already been published and can be reviewed by
independent scientists.
Monsanto welcomed the EFSA review, saying in a statement that its
findings that glyphosate is unlikely to pose a carcinogenic hazard
to humans "align with conclusions from regulatory agencies around
the world".
In contrast, it said, IARC's review "selectively included and
interpreted data, followed non-standard toxicological procedures,
and only reflects the opinions of a select group of scientists".
DIFFERENT FRAMEWORKS
David Coggon, a professor of occupational and environmental medicine
at Britain's University of Southampton, says "it's important to bear
in mind that EFSA and IARC operate within different frameworks".
"The level of precaution that is applied in the face of scientific
uncertainty depends on value judgments, and is not a scientific
question."
Both agencies note that there is some so-called "genotoxic" evidence
that exposure to glyphosate can alter or damage DNA in animal or
human cells, but this evidence is then viewed in different contexts.
For IARC, a World Health Organization (WHO) agency whose lists of
probable and possible cancer risks include high-temperature frying,
shift working and mobile phone use, the glyphosate review was about
the assessment of a potential hazard.
In other words, IARC is tasked with highlighting anything that might
in certain conditions, however rare, be able to cause cancer in
people.
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EFSA, on the other hand, is concerned with real life risks and
whether, in the case of glyphosate, there is evidence to show that
when used in normal conditions, the pesticide poses an unacceptable
risk to human health or the environment.
EFSA's role is to guide policymaking in the European Union, and it
describes itself as an independent agency funded by the EU budget
that operates separately from the European Commission, European
Parliament and EU member states.
IARC's activities are mainly funded by the regular budget
contributions paid by its 25 member states, which include the United
States, Australia and many European countries.
"Which conclusion or opinion is 'correct' depends on your point of
view on the methods used by the two agencies," said Jenkinson. "For
me, the EFSA methodology is the one that is more scientific,
pragmatic and balanced."
BATTLE CONTINUES
The campaign group Greenpeace described the EFSA's review on Friday
as a "whitewash", and the environmental action group the Natural
Resources Defence Council (NRDC) accused EFSA of conducting a
process "that relies on an industry-supplied scientific review".
"The WHO IARC's review is a much more robust,
scientifically-defensible and public process involving an
international committee of non-industry experts," said NRDC
spokeswoman Jennifer Saas.
Yet critics of IARC, which last month classified the consumption of
red meat as probably carcinogenic to humans, say its hazard
identification approach is becoming meaningless for consumers, who
struggle to apply its advice to real life.
"The big problem with IARC ... is that what they're doing is looking
around for any evidence that might enable them to say that under
particular circumstances this thing could be a carcinogen," said
Colin Berry, emeritus professor of pathology at Queen Mary
University of London.
Berry, who declares an interest as having acted as a consultant for
Monsanto, says that since glyphosate is strictly controlled in
agricultural uses and available in only very weak solutions for
regular consumers, its risk is low.
"But these reports worry people," he said. "And I think the process
has lost its usefulness if all it's doing is generating worry."
(Additional reporting by Barbara Lewis in Brussels, editing by Peter
Millership)
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