Facts about Glyphosate (Weed Killer)

Do you know about the safety of glyphosate? Learn now!

In recent weeks, there has been an uptick in the conversation about the safety of glyphosate, a common weed killer, used in our food production.

Below, CRIS experts answer your top questions about glyphosate to keep you in the loop with the latest science:  

What is glyphosate?

Glyphosate is a compound developed and used to kill weeds that compete with crops. It is available for both agricultural and home use.

How is it used?

In agricultural use, glyphosate is typically sprayed on fields at varying stages of plant growth to kill weeds that compete for crop nutrients. When Glyphosate is applied within EPA approved guidelines it does not negatively impact human, animal, or environmental health.

In home use, glyphosate is typically used to reduce weeds and other unwanted growth in gardens, on sidewalks, or in yards. Home use of glyphosate poses no known risk to human or animal health when used in accordance to the manufacturer's instructions. 

Is it dangerous?

Researchers have studied the impact of glyphosate on human, animal, and environmental health for more than 40 years.

We know that glyphosate is safe for humans, animals, and the environment when it’s used in accordance to the EPA’s guidelines.

Can I eat it?

You should never consume concentrated glyphosate! Glyphosate is toxic in concentrated levels. Thankfully you will not find concentrated glyphosate in foods available in grocery stores. However, you will find safe levels of glyphosate residue in some foods.

Concentrated glyphosate is different than glyphosate residue. Glyphosate residue is the incredibly small amount of glyphosate leftover from crop growth, production, and harvest. The EPA has strict guidelines on the amount of glyphosate residue safely allowed in any food.

Calculating Safety

For all EPA approved chemicals, the agency determines the amount of a substance a person can consume before being impacted by adverse health effects. This is called a “reference dose.”

The reference dose is the estimated daily oral exposure to the human population, including sensitive subgroups such as children, that is not likely to cause harmful effects during a lifetime.

The reference dose is expressed in units of milligrams per kilogram of bodyweight per day (mg/kg/day). The EPA reference dose for glyphosate is 1.75 mg/kg/day.

That means if a person weights approximately 80 kg (176 lbs) they would be able to consume approximately 140 mg of glyphosate every day with no adverse health effects.

For a sense of scale, 1mg/kg is to 1 minute in 2 years!

Does glyphosate harm bees?

A recently published study proposes that friendly gut bacteria (i.e., gut microbiota) in bees can be harmed by glyphosate exposure. However, there are questions about the study that need to be addressed before concluding the harmfulness of glyphosate and bee health, including the sample size, exposure levels, and genetic variability between different honey and native bee populations.

While it is well established in scientific literature that animals and insects can experience negative health impacts when friendly gut bacteria are harmed, more in-depth studies are needed before drawing any conclusions about bee gut health and glyphosate. 

How can I tell if the research around glyphosate is sound? 

Glyphosate has been studied by researchers, industry, and government for more than 40 years. These peer-reviewed studies continue to demonstrate the safety of glyphosate when used within guidelines.

Peer-reviewed studies mean that the research and conclusions have been evaluated by non-partial subject matter experts. This peer-review step ensures scientific accuracy and impartiality.

When in doubt, reach out to the experts here at CRIS using the #CRISfacts on Twitter and Facebook or email us directly at cris@msu.edu.

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