Glyphosate in Urine of Danish Dairy Cows: Statement of the Glyphosate Task Force
In a recent study entitled “Field Investigations of Glyphosate in Urine of Danish Dairy Cows” which was published in the Journal of Environmental & Analytical Toxicology, the authors claim to have found correlations between certain blood parameters and varying glyphosate concentrations in the urine of cows. They attempt to link these findings to kidney damage and other health effects in cows.
The Glyphosate Task Force (GTF) has noted the publication1and it is currently being reviewed by scientific experts. However, an initial GTF assessment of the study gives no reason to believe that the results are of any scientific merit, as the authors fail to report any meaningful or relevant data. Concerns of the GTF regarding the credibility of the study are outlined below:
The experimental design failed to include any control group and does not cite any reference values. In addition, the data are presented without individual values or statistical analysis. This makes a meaningful interpretation of the reported measurements impossible.
- Many of the reported analyses depend on nutrition and animal husbandry and therefore would be expected to vary between farms naturally.
- No detail on cattle feed intake or glyphosate concentrations in feed were presented. However, the glyphosate levels reported in urine are well below the European allowable maximum residue levels in cattle feed, based on Good Agricultural Practice.
- Ironically, the cattle with the highest glyphosate levels appeared to be the healthiest, based on milk production. The authors do not report clinical signs or any health concerns in the cows evaluated.
- The presence of glyphosate in urine is expected, since the minute amounts of glyphosate that may be present in cattle feed is rapidly excreted unchanged.
- The reported blood chemistry parameters do not show adverse effects in cattle. However, due to the flawed experimental design a meaningful interpretation of the data is not possible.
- The authors speculate that glyphosate was metabolized after ingestion which resulted in elevated blood urea nitrogen levels (BUN) and that BUN may be a biomarker correlating to kidney damage in cattle. This speculation is not supported by the presented data and contradicts the many in vivo metabolism and toxicology studies, which were performed in multiple species and have been evaluated repeatedly by authorities over the last 40 years of glyphosate registrations. There is no evidence supporting the claims of kidney effects in this study.
- The authors conducted a limited and very biased toxicology literature review citing a short list of selected studies which claim adverse effects. These studies have consistently been rejected by regulatory authorities and toxicologists as inadequate and irrelevant for use in glyphosate risk assessment. The numerous detailed toxicology and epidemiology reviews of glyphosate published by internationaly renowned scientists were excluded by the authors.
All credible scientific studies carried out to date on this issue have concluded that glyphosate is excreted in animals and humans as unmetabolised parent molecule. There has not been any indication of Glyphosate inducing kidney damage. Furthermore, it is important to point out that glyphosate and the primary environmental metabolite, AMPA, have not been reported in the milk of dairy cattle.
The German risk assessment authority, BfR, has published a first assessment of the study on its website: "In a first assessment of the study the Federal Institute for Risk Assessment (BfR) concludes that the reported results do not prove a causal link between glyphosate exposure of the animals and their observed changes of enzyme activities and other laboratory parameters." 2
1 Krüger M, Schrödl W, Neuhaus J, and Shehata AA. Field Investigations of Glyphosate in Urine of Danish Dairy Cows, J Environ Anal Toxicol 2013, 3:5 (an on-line open access journal)
2 Official statement of the BfR "First assessment of glyphosate residues in the urine of dairy cattle" from 20th of September 2013: Stellungnahme Nr. 026/2013 des BfR (in German only).
Last update: 09 September 2014