The herbicide glyphosate was detected in the urine of 99.8 percent of French participants in a study just published inEnvironmental Science and Pollution Research (1). This is yet another demonstration of the pervasiveness of this substance, which was classified in 2015 as a probable carcinogen (Group 2A) by Iarc (WHO’s Agency for Research on Cancer), and authorized until the end of this year, after a five-year renewal obtained on 5.11.2017.
Glyphosate in urine in France
The presence of glyphosate (or glyphosate) in the urine of people (even those not employed in agriculture) has been demonstrated many times. The scarcity of these data with reference to the French has prompted researchers to clarify.
A total of 6,795 people residing in different areas of France and on La Reunion Island, a French overseas department in the Pacific Ocean opposite Madagascar, participated in the study.
The pervasiveness of glyphosate
The measurement of glyphosate levels in the general French population was articulated to highlight the influence of seasons and individual peculiarities, such as biological and social characteristics, dietary habits and occupational exposure.
Analysis showed widespread contamination. An average of 1.19 ng/ml of glyphosate was detected in 99.8% of urine samples. Against LOQ(limit of quantitation) of 0.1 ng/ml.
Men and children more exposed
The highest values belong to men compared to women (1.27 vs. 1.13 ng/ml) and children. In the under-16s, contamination reaches up to 2.05 ng/ml, while in the over-67s it does not go beyond 0.67 ng/ml.
‘Higher levels of glyphosate found in younger participants may be associated with dietary habits (especially children’s cereals), physiology and metabolism (children breathe and drink twice as much as adults), physical activities, behaviors, and hygiene patterns with increased ingestion of (particles of) soil‘, the study authors note.
Less waste with organic food and filtered water
Food and water intake is listed as the primary source of contamination for the general population. The lowest levels of glyphosate belong to participants who
– follow a diet composed of 85 percent organic food (1.16 ng/ml vs 1.17). The organic diet, moreover, has been shown to help rid the body of glyphosate in just a few days, as we have seen,
– regularly drink filtered water (with filters of various kinds: carbon, reverse osmosis, softener). The average value of glyphosate in this group averaged 1.12 ng/ml, lower than regular consumers of tap or spring water, which were found to be contaminated for, respectively, 1.20 and 1.23 ng/ml of glyphosate (a water-soluble substance).
Agriculture and other exposure variables
Occupational exposure is confirmed to be higher. The figure emerges in the over-15s employed in agriculture (1.29 vs. 1.15 ng/ml). And among them, the average exposure is higher for wine workers (1.56 vs. 1.22 ng/ml).
They turn out to be more contaminated with glyphosate, in addition,
– tobacco smokers, as glyphosate is used as a desiccant for some crops before harvest (1.43 vs. 1.16 ng/ml),
– regular consumers of beer (1.37 vs. 1.17 ng/ml) and fruit juice (1.25 vs. 1.16 ng/ml), two foods that have already emerged as more exposed to glyphosate,
– urine samples collected in warm weather, between May and September, when outdoor exposure increases. This finding had already emerged in previous studies. However, according to the researchers, it deserves further study, partly because ‘people may excrete lower volumes of urine during spring-summer than during winter‘ and thus skew the comparison.
Only 1% glyphosate eliminated with urine
The values that emerged from the study under review seem to represent a miniature of what is happening. In fact, the sample consists of volunteers who are sensitive to the danger of herbicide and pesticides in general. Indeed, it has a large share of organic food consumers, non-smokers and farmers.
Moreover, the data presented must be evaluated knowing that the amount of herbicide excreted with urine is very small.
‘Until recently, data were only available from studies in laboratory animals, with excretion rates of about 20 percent of an orally administered dose of glyphosate (EFSA 2015 ). It was recently shown, however, that only about 1% of the glyphosate dose was excreted in human urine within 44 h (Faniband et al. 2021 ). Accurate quantification of exposure, both internally and externally, is a major public health concern because toxicity assessment is based on absorbed dose estimates (IARC 2015 )‘, highlight the study authors.
Marta Strinati
Cover image from blagues & dessíns, L’actu de Mikolas (2017). Du glyphosate dans les urines des Français
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
