It’s likely
we’ve all seen the popular media press about court cases against the
manufacturer of Roundup and other glyphosate producers. This has caused
considerable concern for some people who would otherwise benefit from its use
for controlling competing and invasive vegetation. The media is effective
at raising alarms, but less so about a thoughtful analysis of the science.
What follows
is an article first published in the Branching Out Fall 2019 newsletter
from the University of Maryland Cooperative Extension. It provides a thoughtful
analysis of the concerns about glyphosate. The author, Jonathan Kays, discusses
Roundup and similarly categorized products relative to their chemistry, use,
and how it is viewed by different agencies and organizations. In addition,
links to reference material are provided. Please take some time to give it a
read.
What’s Going on With Roundup®?
Compiled by Jonathan
Kays, University of Maryland Extension Forestry Specialist
(Reprinted
from Branching Out newsletter, Fall 2019, with permission from the
author)
The news
media is full of offers to join class action lawsuits against glyphosate, the
active ingredient in many herbicide formulations, including Roundup®. High
profile lawsuits in California have successfully sued Monsanto, the original
manufacturer of Roundup. The assertion was that their clients’ long-term use of
Roundup® caused the plaintiffs' cancer.
I am not a
toxicologist, I am an extension forester and a faculty member at a land-grant
university who is committed to looking objectively at scientific data and
making recommendations. In this case the lawsuits and media do not seem to match
with the science.
So why is
glyphosate so important? Controlling undesirable vegetation in forestry is
critical to assuring a healthy forest, establishing forest regeneration,
creating wildlife habitat, and controlling invasive plants. Controlling
undesirable vegetation is possible by using prescribed fire, mechanical tools
and equipment, and possibly even goats, but herbicides are much more effective
and efficient. In fact, mechanical control methods may pose a greater safety
threat for human injury.
Glyphosate
is a type of herbicide that has an active ingredient that interferes with plant
growth. Glyphosate works by blocking the activity of an enzyme in the one of
the biochemical processes so that the plant cannot grow. The process is found
only in plants and not in humans and other animals. Monsanto marketed
glyphosate as Roundup® in 1974 and held the patent on the chemical until 2000.
The patent expired in 2000, allowing companies to legally produce and sell glyphosate,
and at lower cost, which is where we are today.
Glyphosate
is found in many formulations and trade names and is sold in big box stores and
through agricultural dealers. It is widely used in forestry, agriculture, and
residential markets to control unwanted vegetation. It works on all types of
plants, becomes inactive in the soil, breaks down quickly in sunlight, and
poses little danger to the environment. Glyphosate, like every chemical active
ingredient for any herbicide, goes through an assessment by the Environmental
Protection Agency (EPA), which determined it to be safe when used “according to
the label directions.” The label is the law.
Some recent
court verdicts in California have found glyphosate responsible for causing
non-Hodgkin’s lymphoma (NHL). Scientists do not really know what causes this
cancer. If glyphosate caused cancer at realistic exposure levels, then farmers
and other applicators would be the first to show this effect. The largest study
ever published (see references), looking at farmers and other applicators,
found no association between glyphosate and solid tumors, including NHL.
Anti-glyphosate
advocates point to the 2015 report from the International Agency for Research on
Cancer (IARC, www.iarc.fr), an arm of the World Health Organization. The report
labeled glyphosate a probable human carcinogen, a determination that was
surprising to many. IARC responded to critics by clarifying their intent – to
identify potential hazards. They asked, “Can it cause cancer under any circum-stance?”
They defer to others to do risk assessment based on expected levels of exposure
and background cancer rates. Most governments (US, Europe, Australia, New
Zealand, and Canada) have published risk assessments about glyphosate, finding
it unlikely to cause cancer in humans when used according to label directions.
The EPA
under the past four administrations found glyphosate to pose no risk to human
health and was not a carcinogen. Likewise, the European Chemicals Agency
determined glyphosate was not a carcinogen, and in 2018 the European Food
Safety Authority determined the current exposure levels are not expected to
pose a risk to human health.
The IARC
determination put the following items in the same “probable human carcinogens”
category as glyphosate: consumption of red meat, drinking very hot beverages, high
temperature frying emissions, late-night shift work, hairdresser workplace
exposure. “Known human carcinogens” on their list included processed meat,
alcoholic beverages, and sunlight. Hazard identification is only the first step
in assessing risk.
Glyphosate
use in forest management is critical for controlling undesirable vegetation and
using it according to labeled directions minimizes risk. As with any pesticide,
risk is reduced by using the Personal Protection Equipment detailed on the product
label, such as proper clothing, gloves, eye protection, etc. To do otherwise is
using the material illegally. Determinations by courts and lawyers do not
necessarily reflect the science on this subject. I encourage you to review the
references provided below and make your own decision. If use of glyphosate can
be banned based on the science available, the obvious question is, “What’s
next?”
Information
for this article was drawn from the following sources:
· Coyle, D. R. (2019). Glyphosate: Cause for
Concern?. Forest Landowner, November/December 2019, 25-38. Retrieved from http://southernforesthealth.net/other/general-forest-health/glyphosate-cause-for-concern
· Buhl, K.& Bubl, C. (2018). Glyphosate
Questions & Answers. Oregon Master Gardener Coordinators. OSU Extension
Master Gardener Program. Retrieved from http://blogs.oregonstate.edu/mgcoordinators/2018/10/15/glyphosphate-questions-answers/
· Andreotti, G., Koutros, S., Hofmann, J.N.,
Sandler, D.P., Lubin, J.H., Lynch, C.F., … Beane Freeman, L.E. (2018).
Glyphosate Use and Cancer Incidence in the Agricultural Health Study. JNCI:
Journal of the National Cancer Institute, 110(5), 509–516. Retrieved from https://doi.org/10.1093/jnci/djx233
· Kniss, A. (2018) Glyphosate and cancer –
revisited. Retrieved from
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