Review of genotoxicity studies of glyphosate and glyphosate-based formulations

Abstract

An earlier review of the toxicity of glyphosate and the original Roundup™-branded formulation concluded that neither glyphosate nor the formulation poses a risk for the production of heritable/somatic mutations in humans. The present review of subsequent genotoxicity publications and regulatory studies of glyphosate and glyphosate-based formulations (GBFs) incorporates all of the findings into a weight of evidence for genotoxicity. An overwhelming preponderance of negative results in well-conducted bacterial reversion and in vivo mammalian micronucleus and chromosomal aberration assays indicates that glyphosate and typical GBFs are not genotoxic in these core assays. Negative results for in vitro gene mutation and a majority of negative results for chromosomal effect assays in mammalian cells add to the weight of evidence that glyphosate is not typically genotoxic for these endpoints in mammalian systems. Mixed results were observed for micronucleus assays of GBFs in non-mammalian systems. Reports of positive results for DNA damage endpoints indicate that glyphosate and GBFs tend to elicit DNA damage effects at high or toxic dose levels, but the data suggest that this is due to cytotoxicity rather than DNA interaction with GBF activity perhaps associated with the surfactants present in many GBFs. Glyphosate and typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures.

• Formulation
• genotoxicity
• glyphosate
• mutagenicity
• Roundup™

Acknowledgements

The authors would like to thank the following individuals for their contributions to this work by providing regulatory studies and their thoughtful review of the manuscript: David Saltmiras (Monsanto Company), Christian Strupp (Feinchemie Schwebda GmbH), Terri Spanogle (Cheminova A/S), Jürgen Wenzel (HELM AG), Andrew Bond (Nufarm Limited), Sylvain Gautier (Arysta LifeScience Corporation), Simon Hill (Syngenta AG), Ganesh Shetgaonkar and B.M. Ravikumar (Excel Crop Care Ltd.). We would also like to acknowledge David Saltmiras for his invaluable service in providing coordination with individual companies and the Glyphosate Task Force.