Research in Germany has shown that all city dwellers have glyphosate in their urine, even if they avoid products that they believe contain GMOs or the associated pesticides. Should I welcome this news, because it is certainly far better than having radioactive substances in my body? Or, since glyphosate has been show to cause sterility after a few generations, should I relocate to a planet with more favorable ecology and business leaders?

Expert response from John Swarthout, Ph.D.

Scientific Outreach and Issues Management Lead, Bayer Crop Science

Monday, 04/11/2013 22:08

Regarding glyphosate in the urine, the study you are referring to was conducted by a German non-government organization known as BUND (Association for Environment and Nature Protection―German branch of Friends of the Earth) and is titled “Determination of Glyphosate residues in human urine samples from 18 European countries.” The study looked for the presence of glyphosate in 182 urine samples collected from 18 different countries. Many of the samples collected were negative for glyphosate, and when glyphosate was found, it was far below what the European Union considers as its acceptable daily intake. While there are no details on sample collection or possible dietary or operator exposure of the people from whom these samples were taken, I can safely say that there is nothing new or surprising to report from the results of the study, and that low levels of glyphosate are permitted in food and are considered safe. In fact, it is not surprising to find glyphosate in urine, should a person ingest food with low residues of glyphosate. Why? Well, because this is exactly where it should be. A fraction of glyphosate is absorbed after ingestion, and the remainder is excreted in feces.  Absorbed glyphosate is not metabolized by the human body but excreted in urine.  Furthermore, all independent health assessments conducted by public authorities in Europe and internationally over the past 40 years have consistently concluded that glyphosate does not pose any unacceptable risk to human health.

If you are still apprehensive about the possibility of glyphosate in your urine, perhaps taking a deeper dive into the details of the study will help. For example, look at the levels of glyphosate reported in the study. As stated above, many of the samples tested were negative, and of the ones that did contain glyphosate, the highest value observed was still less than two micrograms per liter (two parts per billion).  This translates to an intake that is over 1,000 times lower than what the European Union considers as its acceptable daily intake (0.3 mg/kg body weight per day), and more than 3,500 times lower than the equivalent value from the World Health Organization (1.0 mg/kg body weight/day). These values are considered a safe oral exposure every day throughout a person’s life, without incurring any appreciable health risk.

(Calculation is below.)

Now let’s discuss your statement that glyphosate causes male sterility. This is simply not true. Let’s examine the source of your claim. I think the study you are referring to is by Clair et al., and it looks at the effect of glyphosate formulations on cells from the testis. These experiments from this study demonstrate what we already know: substances can injure unprotected cells in a test-tube.

Experiments performed in a petri dish in a laboratory often are not representative of exposures to a living animal and are not informative about real-world risks to humans. Furthermore, it should not be a surprise that a glyphosate-based formulation that contains surfactants (detergents), similar to detergents found in household and personal-care products (e.g., bath gels, hand soaps, shampoos and laundry and dishwashing detergents), would have an effect on cellular membranes. Cellular membranes contain lipids (grease, if you will), and detergents are designed to be tough on grease, so adding detergents directly to cells will disrupt them.

For some additional perspective, the exposure of people to surfactants is common, and adults and children consume residues of detergents from utensils, dishes and glasses washed with dish-washing detergents that have the same ability to disrupt membranes. Yet you eat and drink every day with no appreciable harm. So while you can take shampoo and put it on some cells in a petri dish in the lab and the cells will die, washing your hair every day with that same shampoo will not make you sterile.

Here is the calculation:

The highest value found in the study was less than 2 micrograms per liter (two parts per billion).  A simple calculation shows that, as people typically produce about 2.5 liters per day, then this highest value indicates the maximum systemic dose was 5 micrograms.  Oral intake to reach a systemic dose of 5 micrograms (30 percent gastrointestinal absorption) would be 16.7 micrograms ingested glyphosate; for a 60-kilogram person, this would be a dose of 0.28 micrograms glyphosate per kilogram of body weight (or 280 nanograms of glyphosate per kilogram), over 1,000 times lower than the EU acceptable daily human exposure level (considered a safe oral exposure every day throughout person’s life without that person incurring any appreciable health risk).

This is unlikely to be of any significance to health because it is more than 1,000 times lower than the acceptable daily intake established by the European Union, and more than 3,500 times lower than the equivalent value from the World Health Organization. The acceptable daily intake is the amount that can be consumed without cause for concern, even for the most vulnerable groups, and includes significant safety factors.

• The EU acceptable daily intake (ADI) is 0.3 mg/kg/day, or 300 ug/kg/day.
• The 5 ug number from the BUND study gives a daily systemic dose of 0.083 ug/kg/day for a 60 kg person (5/60), which equates to 0.083 x 100 / 30 = 0.280 ug/kg/day ingested glyphosate.
• 300 divided by 0.280 is 1,000 times lower that the ADI for a 60 kg individual.
• Even if you do the math for a 10 kg child, you get ~ 176 times lower than the ADI.