Toxicity of glyphosate, myth or reality?
In order to develop an understanding of the role of adjuvants in a popular glyphosate-based herbicide – Roundup® Concentrate Plus (RCP), on non-target organisms, the effects of pure glyphosate [N-(phosphonomethyl)-glycine], RCP and a non-ionic surfactant – polyethoxylated tallowamine (POEA) were studied in the fruit fly Drosophila melanogaster.
Fig.: No deleterious effect was observed after exposure to glyphosate alone, whereas exposure to RCP or POEA caused damage to Drosophila.
Our results suggest the possibility that toxic effects of glyphosate based herbicidal formulations may be due to the surfactants/adjuvants such as POEA along with other formulants. Moreover, our results characterize the RCP and the surfactant POEA as possible disrupters of fecundity in non-target organisms at sub-lethal concentrations. Exposure to both RCP/or POEA but not pure glyphosate alone promoted an increase in oxidative damage (as revealed by protein carbonyl levels) while reducing lifespan. Decreased fecundity is probably due to increased caspase activity indicative of proapoptotic events as revealed by in vitro studies. In conclusion, the results suggest that RCP and the surfactant POEA are more toxic than pure glyphosate.
Bednářová A., Kropf M., Krishnan N. (2020) The surfactant polyethoxylated tallowamine (POEA) reduces lifespan and inhibits fecundity in Drosophila melanogaster- In vivo and in vitro study. Ecotoxicology and Environmental Safety 188: article number: 109883. DOI: 10.1016/j.ecoenv.2019.109883