Input On Glyphosate Sought – Expert Reaction

Credit: Original article can be found here

Industry and the public are being asked for
information about the use of the herbicide glyphosate, in a
new consultation by the EPA.

Glyphosate is used in
weed killers, such as Roundup, by gardeners, farmers and
councils, but the possible environmental and health effects
have been subject to public

The EPA’s position, similar to
Australia, Canada, the US and the EU, is that glyphosate
products are safe as long as all the rules for use are
followed. Glyphosate use is currently being reviewed in

The SMC asked experts to comment on the
EPA’s call for information on glyphosate use.

Belinda Cridge, mechanistic toxicologist and Technical Lead
for Drinking Water, Institute of Environmental Science and
Research (ESR), comments:

“As a toxicologist, while
I do not have serious concerns about the toxicity of
glyphosate, I welcome this inclusive call for information.
Our understanding of chemicals develops over time and it is
incumbent upon the EPA to continually reassess current
literature, knowledge, and social acceptance of the
chemicals we use.

“With major reviews occurring in
the US and EU to update our understanding of the risks and
benefits of glyphosate use, it is important that the EPA has
New Zealand-relevant information to allow decisions as to
the future use of the chemical here. The work of the EPA in
seeking this information proactively is appropriate and will
add a great deal of context to the overall risk assessment
for this chemical. I would encourage people who have
concerns or comments about glyphosate use in New Zealand to
participate in this process to allow their insights to be

No conflict of

Professor Ian Shaw, Professor of
Toxicology, University of Canterbury, comments:

was (and remain) amazed that the EPA decided not to include
glyphosate in its review of pesticides and related
chemicals. The news that they are calling for information on
its use is encouraging because it suggests that they might
at least be interested in considering its potential
environmental and human health impact.

“I was so
surprised that the EPA decided not to review glyphosate that
I undertook a review of its chemistry, use and toxicity to
both humans and ecosystems as a means of assessing its risk
(this will be published in the New Zealand Science

“My conclusion was that glyphosate’s
acute effects in both humans and on the environment are
likely negligible, but that we have too little data to
determine its long-term effects

“However, the available data point
firmly to long-term environmental effects and effects in
workers handling glyphosate regularly without appropriate
personal protective equipment. In contrast, the recent
reports of residues in food (e.g. honey) are very unlikely
indeed to negatively affect consumer health.“

conflict of interest declared.

Associate Professor
Brian Cox, Director of the Hugh Adam Cancer Epidemiology
Unit, University of Otago, comments:

“In 2015, the
International Agency for Research on Cancer (IARC)
classified glyphosate, a major ingredient of many weed
killers, as a probable carcinogen (a possible cancer-causing
agent in their Group 2A category). That is, the IARC
considered there was limited evidence that glyphosate may
cause cancer, but any association with cancer may be due to
other things. Herbicide use is seldom exposure to just one
specific product, and the dose, duration, type, and
frequency of exposure is relevant to any potential

“It is appropriate that the EPA in New Zealand
reviews the use of glyphosate and the manner in which people
may become exposed to it during its use. This is necessary
to assess the balance of the evidence of risk from the use
of glyphosate and the views of users, the public, and New
Zealand industry.

“The IARC definition of Group 2A
is: the agent is probably carcinogenic to humans. This
category is used when there is limited evidence of
carcinogenicity in humans and sufficient evidence of
carcinogenicity in experimental animals. Limited evidence
means that a positive association has been observed between
exposure to the agent and cancer but that other explanations
for the observations (called chance, bias, or confounding)
could not be ruled out. This category is also used when
there is limited evidence of carcinogenicity in humans and
strong data on how the agent causes cancer.”

conflict of interest.

Dr Kerry Harrington, Senior
Lecturer in Weed Science, Massey University,

“It is concerning that policy over
glyphosate in Europe appears to be more swayed by public
perceptions than facts. Most toxicologists across the world
now agree that glyphosate is unlikely to cause cancer in

“If glyphosate was to be removed from use,
the possible replacements are either less effective or
likely to be more damaging to the environment than
glyphosate. The use of this herbicide in agriculture has
enabled much more use of direct drilling when establishing
crops and pastures, thereby reducing soil erosion, and no
other herbicide can be used to allow satisfactory direct
drilling without weed problems afterwards. (Direct drilling
involves establishing crops without cultivating the

“Councils will have difficulties keeping
weeds under control in our communities without needing to
increase costs considerably from using less effective
alternatives. But the EPA in New Zealand will hopefully use
this exercise to reassure themselves and the community that
it is correct to continue using glyphosate within New

Conflict of interest statement: “I
work with people throughout New Zealand to develop efficient
weed control practices. But I am paid only by my university
and do not derive income from chemical companies or other
such bodies, apart from some paying for their staff to
attend a 3-day short course to help them understand

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