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!

Monday, February 25, 2013

GMO Food Safety

There is a lot of misinformation floating about the web regarding the politically charged topic Genetically Modified Organisms (GMO) and food-safety. Here, I will chronicle such false and/or misleading claims, as I come up against them. Hopefully someone out there will appreciate my personal journey to elucidate the facts behind the lies told in the interest of scaring gullible people.

Velimirov et al. 2008

This study was cited as a source in some trashy blog (which I refuse to link to), parading the fear that GMO corn could cause sterility in humans. The study examined the reproductive outcomes, organs, and DNA of mice (not humans!) fed GMO corn (NK603 and MON810). The study reported that a diet of GMO corn:
... affected the reproduction of mice.
And that:
... differences between the groups became obvious in the 3rd and 4th litters.
In march, 2010, the study was finally withdrawn (Source) by the Austrian government.

I found one response which identified many of the same flaws with the experiment as I noticed upon slogging through the 105 page paper:

  • The mice fed non-GMO corn were underweight!
  • The mice fed GMO corn lived longer! (15.7 in control, 17.0 in GM group)
  • A lot of mice seemed to die! (1% mortality is normal, 8% was reported)
  • The two most important tables involving reproduction contained errors! (Fraud...?)

Most importantly, the study was never published in any peer reviewed journal!

Verdict? Debunked.