Forty Years with Glyphosate

Re-registration Challenges of Glyphosate in the European Union

“…As pointed out earlier (Székács and Darvas, 2012), glyphosate and AMPA used to be detected in environmental studies previously less frequently due to the limited sensitivity of the traditional analytical methods based on gas chromatography. This has created an advantageous reputation for glyphosate of being environmentally benign.…”

“…Risks related to glyphosate may originate from increasing residue levels and incidence due to increased usage; and from modified residue composition due to the use of GT crops. Increasing use of glyphosate on GT crops and also as a crop desiccant on non-GT crops, and its subsequent release into the environment is seen both in increased residue levels found in environmental matrices, first of all drinking water (see below, Environmental and food analysis of glyphosate) and in more frequent occurrence reported, on the basis of which glyphosate and AMPA have been considered as ubiquitous surface water contaminants (Villeneuve et al, 2011;Székács and Darvas, 2012). These trends both increase risk through exposure.…”

“…In addition, expanding applications of GT crops have modified residue composition: while a type of GT crops modified with a cp4-epsps gene achieves tolerance to glyphosate by expressing enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme derived from Agrobacterium sp. strain CP4 not inhibited by glyphosate, other types of these GT plants modified with gox or gat genes provide tolerance to the compound by its enhanced degradation by transgenic metabolic enzymes, glyphosate oxidoreductase (GOX), or glyphosate acetyltransferase (GAT) expressed in the plant, leading to increased levels of the main metabolite AMPA (Székács and Darvas, 2012;Myers et al, 2016). Therefore, risk assessment has to consider such modified exposures to glyphosate and AMPA (Vandenberg et al, 2017) and other metabolites.…”

“…FIGURE 1 | The global annual turnover of glyphosate and the intensity of the cultivation of glyphosate-tolerant (GT) genetically modified (GM) crops: agricultural (slashed line), non-agricultural (dotted line) and overall (solid line) use of glyphosate, along with cultivation of single trait (light columns) and multiple traits (dark columns) GT GM crops. On the basis of Székács and Darvas (2012), Benbrook (2016), Cuhra et al (2016), Myers et al (2016) and the updated dataset of the International Service for the Acquisition of Agri-biotech Applications (James, 2015). The re-registration process took an unexpected turn that triggered wide public responses, when the renewal of the authorization of glyphosate, along with 38 other pesticide active ingredients, was postponed until 2015 (European Commission, 2010) and to be completed only in 2016.…”

“…Since its introduction as an herbicide active ingredient in 1971 (Baird et al, 1971), glyphosate [N-(phosphonomethyl)glycine] became and remains the market leading herbicide active ingredient worldwide (Dill et al, 2010;Székács and Darvas, 2012;Benbrook, 2016). Its initial patent protection commenced in 1971 (Franz, 1974), and was renewed in the eighties on the basis of novel composition-through a process that involved property acquisitions among major pesticide companies.…”