Portland landscape and pruning design

Ingesting 3/4 cup Glyphosate lethal?

Hmmm ?

Copyright 2010 by Mario D. Vaden


One of the most extreme comments I ever read online to defend an opinion about Roundup, was about ingesting it. Apparently, they got the information from a publication called A Year on the Garden Path.

The claim was that "Ingesting three-quarters of a cup can be lethal" from Ten Things You Should Know About Roundup ®

Personally, I don't advocate using a lot of Roundup. But I'm not afraid of herbicides like that either. My teaching about those products is to use as little as possible. If none can be used, all the better. But I don't jump on folks for using tiny amounts sparingly, or try to freak them out.

When we realize how many chemicals we breath-in daily in urban areas, miniscule quantities of Roundup (Glyphosate) may seem inconsequential. Carpets release chemicals, automobiles release chemicals, Contractors spraying home interiors in your neighborhood release chemicals, and so on. Every breath you take is should be loaded with thousands of molecules and dozens of chemicals in trace amounts.

Anyhow, people with a strong stand against Roundup may have a point when they talk about effects of Glyphosate on mycorrhizal fungi, earthworms, or trace residue in soil or vegetables. But if they are going to talk about drinking Glyphosate in a cup, I'm game for cutting that aspect of their argument at the knees. If we want people to believe us, we can't be extreme.

How many people do you know who drink Roundup?

You want to know how many I've seen do this? How about zero.

The article that introduced this extreme example was about Roundup. Now, Roundup is not the same as Glyphosate, but contains it. Pre-mix bottles of Roundup have like 2% or 4% Glyphosate. The concentrate bottles used to be something near 18% back in the 1980s. And today, maybe near 41%: close to half.

That means someone would need to drink nearly 1.5 cups to 3 cups of nasty bitter Roundup herbicide to ingest the theoretical lethal dose.

Personally, I've never heard of anybody drinking an ounce of it, or an eyedropper dose. The entire example seems over the top.

As for spraying, even then the residue is very diluted. Suppose the concentrate was a 50% concentrate. That means that 2 ounces of Roundup would only have an ounce or so of Glyphosate. Then that ounce is diluted into a full gallon. And that entire gallon is dispersed over as much as 300 to 3000 square feet depending on whether you use mist, droplets, spot-spray or full-coverage-spray. Its applied in very small amounts and has nothing to do with drinking.

So just do your best to sanely reduce your herbicide use if possible. If you have to spray, spraying weeds more often and when they are tiny uses less herbicide than doing it infrequently and after they have grown much bigger leaves. If you pump the pressure too high, the herbicide will drift and pollute the air needlessly, and waste product. If you can smother weeds with mulch, or tarps temporarily, you may not need to spray. And if you can get the situation under control and apply a nice layer of mulch, weeding by hand or tools may work fine.

Keep in mind that the 3/4 cup ingestion statement was listed with 9 other fairly realistic pieces of information. But when something this extreme is tossed into the arena of argument, that's an alarm to look at the other bits of information and pay close attention to what is said, and what may be omitted.

Because we don't need to go overboard about toxicity issues. Glyphosate has some degree of toxicity. As does alchohol, table salt, carbon dioxide and even water. You have heard about people dying from drinking gallons of water haven't you?. We just need to state the facts and pick points of reason that will stick.

Even with points of reason that stick, think about them. Take worms for example. What if Glyphosate really does reduce populations of worms? How would that compare to you taking a rototiller through your garden and crushing worms by the hundreds? Does this comparison help sway you one way or the other?