vs. Genotoxicity Paper
“How did the U.S. “, Environmental Sciences Europe, January 15, 2019, DOI: 10.1186/s12302-018-0184-7. and reach diametrically opposed conclusions on the genotoxicity of glyphosate-based herbicides?
By: Charles Benbrook, PhD
- Access paper (free)
- Access Supplemental Tables
- Access Editorial Statement “Some food for thought – A short comment on Charles Benbrook’s paper “How did the U.S. ,” by Henner Hollert and Thomas Backhaus, DOI: 10.1186/s12302-019-0187-z and reach diametrically opposed conclusions on the genotoxicity of glyphosate-based herbicides?” and its implications
- “Why I Wrote the Glyphosate Genotoxicity Paper” — blog by Dr. Benbrook
Genotoxicity studies cited in Glyphosate Issue Paper: Evaluation of Carcinogenic Potential” and in the glyphosate chapter of ’s 2017 carcinogenicity evaluation “Monograph 112: Some ” are compared and contrasted. and herbicides’s 2016 “
Key findings are highlighted below. The graphics are available in different formats (see below).
Whilereferenced only peer-reviewed studies and reports available in the public literature, relied heavily on unpublished regulatory studies commissioned by pesticide manufacturers. In fact, 95 of the 151 genotoxicity assays cited in ’s evaluation were from registrant studies (63%), while cited 100% public literature sources.
There is also a stark difference in the outcomes of registrant-sponsored assays versus those in the public literature. Of the 95 regulatory assays taken into account by, only 1 reported a positive result, or just 1%. Among the total 211 published studies (right circle in the graphic), 156 reported at least one positive result, or 74%!
Another important difference is thatfocused their analysis on glyphosate in its pure chemical form, or “glyphosate technical.”
, on the other hand, placed considerable weight on 85 studies focused on GBHs, the herbicide people actually use and are exposed to (“Glyphosate Herbicides” in the graphic). 79% of the GBH assays published in public literature reported one or more positive result.
Whiledid list studies on glyphosate-based herbicides (GBHs) in an Appendix F of its report, acknowledges it placed little to no weight on GBH assay results.
This difference is reflected in the overall percent of positive assays. Just 24% of the 151 assays cited byreported positive results, while 76% of those cited by had at least one positive result.
Key Finding #3
’s analysis was limited to typical dietary exposure to the general public as a result of legal uses on food crops, and did not address occupational exposure and risks.
’s assessment encompassed data from typical dietary, occupational, and elevated exposure scenarios. Elevated exposure events caused by spills, a leaky hose or fitting, or wind are actually common for people who apply herbicides several days a week, for several hours, as part of their work. The highest exposures typically occur when herbicides are applied with a handheld or backpack sprayer, or an ATV or truck-mounted sprayer.
The equipment used to apply GBHs has a huge impact on applicator exposures, as does whether applicators use Personal Protective Equipment like gloves. The applicator driving the modern, large-scale sprayer pictured on the left might typically spray around 500 acres in an 8-hour day, apply 700 pounds of glyphosate technical, and be exposed to 3.5 milligrams (3,500 ug, or). The applicator using a backpack sprayer without gloves would apply only about 3 pounds of glyphosate in 8 hours, but would be exposed to around 175 milligrams of glyphosate, 50-times more than the driver of the spray rig. And that driver would spray more than 230-times more glyphosate in an 8 hour day. In virtually all high-exposure scenarios, wearing gloves makes a big difference, reducing exposures by around one-half to one-tenth of “no gloves” exposure levels. The estimated exposures in the scenarios in the graphic represent applications during which everything goes “by the book,” but in the real-world a variety of factors can, and frequently do dramatically increase exposure levels.
Key Finding #4
A closer look at the assays referenced bybut not , and by but not helps explain why and reached opposite conclusions.
cited 109 total assays not included in the report, 87% of which were regulatory studies commissioned by industry, and all but one was negative.
included the results from 67 assays not included in ’s analysis, all of which were from peer-reviewed publications, and 82% of which had at least one positive result for genotoxicity.
- Infographic of Key Finding #1 and 2
- Graphic of Key Finding #3
- Graphic of Key Finding #4
- All Graphics – .png format
- All Graphics – .pdf format
- “Glyphosate Issue Paper: Evaluation of Carcinogenic Potential,” ’s Office of Pesticide Programs (OPP), September 16, 2016 (227 pages)
- ”Revised Glyphosate Issue Paper: Evaluation of Carcinogenic Potential,” ’s Office of Pesticide Programs, December 12, 2017 (216 pages)
- “Summary of ORD [EPA Office of Research and Development] comments on OPP’s cancer assessment,” December 15, 2015 (3 pages)
- Glyphosate Section from Volume 112 of the Monograph Series (92 pages)
- “Q&A on Glyphosate,” March 1, 2016 (3 pages)
- “Briefing Note for ,” January 2018 (11 pages) Scientific and Governing Council Members Prepared by the Director
- “, ” Prepared by the response to criticisms of the Monographs and the glyphosate evaluation Director, January 2018
- General Q and A on the Monographs
- Smith et al., “Key Characteristics of ,” Environmental Health Perspectives Vol 124(6), June 2016 as a Basis for Organizing Data on Mechanisms of Carcinogenesis
- Michael Davoren and Robert Schiestl, “Glyphosate-based herbicides and cancer risk: a post-h,” in Carcinogenesis, October 2018 decision review of potential mechanisms, policy and avenues of researc
- Peter Infante et al., “ Monographs Program and public health under siege by corporate interests,”
- Kongtip et al., “Glyphosate and Paraquat in Maternal and Fetal Serums in Thai Women,” Journal of Agromedicine, American Journal of Industrial Medicine, April 2017
- Szepanowski et al., “Differential impact of pure glyphosate and glyphosate‑based herbicide in a model of peripheral nervous system myelination,” Acta Nueropathologica, 2018
- Santovito et al., “,” Environmental Science and Pollution Research, 2018 evaluation of genomic damage induced by glyphosate on human lymphocytes
- National Toxicology Program poster presentation on glyphosate genotoxicity, 2018
- Milic et al., “ Archives Hig Rata Toksokol, 2018 , cholinesterase activity, and DNA damage in the liver, whole blood, and plasma of Wistar rats,”
- Sophie Richard et al., “Differential Effects of Glyphosate and Roundup on Human Placental Cells and Aromotase,” Environmental Health Perspectives Vol 113(6), 2005