The Physics Police

The Physics Police

Thursday, February 28, 2013

Glyphosate in Pee

Glyphosate is the active ingredient in Monsanto's herbicide called Roundup. I've lately read a lot of accusations that this substance is a poison. Well, yes, it is a poison... to plants. But let's look into it further.

Human health.
Glyphosate's mode of action is to inhibit an enzyme involved in the synthesis of the aromatic amino acids: tyrosine, tryptophan and phenylalanine. We derive plenty of these amino acids from our food, and our bodies are so large that you'd have to drown in the stuff to suffer from amino acid deficiency. Don't take my word for it, though:
There is no potential for Roundup herbicide to pose a health risk to humans. (Source)
Many have questioned the above study, from 2000, but the results were upheld by a 2001 EU study.

Someone pointed out to me that use of Glyphosate may produce super weeds that are resistant to its herbicidal effects. Any chemical used to kill organisms includes the risk of encouraging resistance to that chemical. Farmers have to use herbicides. The question is, which ones do the least harm? Consider the alternatives: dioxins, chlordane, DDT, etc. If the worst thing you have to say about an herbicide is that weeds may develop resistance to it...

I was heard that Roundup is to blame for Colony Collapse Disorder! As it happens, Glyphosate is:
Non-toxic to honeybees on an acute oral and acute contact basis. (Source)
A hilarious publication out of Berlin reports that some people had concentrations of Glyphosate in their urine that were many times the safe concentrations in drinking water! Since Glyphosate does not bio-accumulate, it is concentrated in the urine as it is excreted from the body. So, unless your going around drinking people's urine, you should be fine. Ha ha, Germany, what will we do with you?

But seriously, the maximum amount found in urine may be 20 times the limit for safe drinking water, but that's only 5 parts per billion. Took me some work to convert from their units:
2 ng/ml = 2 * (10^-6 mg) * (10^-3 liter) = 2 * 10^-3 ppm = 2 ppb
Only two parts per billion, that's a very, very low concentration of chemical! The legal limits on uranium in the drinking water is 30 ppb. For arsenic, it's 10 ppb. For lead it's 15 ppb. And the concentration dangerous to mammals? Well, it's in excess of:
5,000 mg/kg = 5 * 10^-3 = 1 million ppb
Yes, you read that right. One million parts per billion. That's half a million times more Glyphosate than is in the European urine!

No comments:

Post a Comment