Genotoxicity Expert Panel review: weight of evidence evaluation of the genotoxicity of glyphosate, glyphosate-based formulations, and aminomethylphosphonic acid

Abstract

published a monograph concluding there was strong evidence for genotoxicity of glyphosate and glyphosate formulations and moderate evidence for genotoxicity of the metabolite aminomethylphosphonic acid (AMPA). These conclusions contradicted earlier extensive reviews supporting the lack of genotoxicity of glyphosate and glyphosate formulations. The IARC Monograph concluded there was strong evidence of induction of oxidative stress by glyphosate, glyphosate formulations, and AMPA. The Expert Panel reviewed the genotoxicity and oxidative stress data considered in the IARC Monograph, together with other available data not considered by IARC. The Expert Panel defined and used a weight of evidence (WoE) approach that included ranking of studies and endpoints by the strength of their linkage to events associated with carcinogenic mechanisms. Importantly, the Expert Panel concluded that there was sufficient information available from a very large number of regulatory genotoxicity studies that should have been considered by IARC. The WoE approach, the inclusion of all relevant regulatory studies, and some differences in interpretation of individual studies led to significantly different conclusions by the Expert Panel compared with the IARC Monograph. The Expert Panel concluded that glyphosate, glyphosate formulations, and AMPA do not pose a genotoxic hazard and the data do not support the IARC Monograph genotoxicity evaluation. With respect to carcinogenicity classification and mechanism, the Expert Panel concluded that evidence relating to an oxidative stress mechanism of carcinogenicity was largely unconvincing and that the data profiles were not consistent with the characteristics of genotoxic carcinogens. ARTICLE HISTORY

A review of the carcinogenic potential of glyphosate by four independent expert panels and comparison to the IARC assessment

“…The genetic toxicology Expert Panel (Brusick et al 2016) considered published studies reviewed in the IARC monograph and additional published studies identified by literature searches or from review articles, not considered by IARC. These included both genetic toxicology studies and studies of oxidative stress.…”

Re-registration Challenges of Glyphosate in the European Union

“…A large team of researchers including 96 research professors from 22 countries worldwide (Portier et al, 2016) analyzed the data. Taking a contrary position were a set of six studies published in the journal Critical Reviews in Toxicology (Acquavella et al, 2016;Brusick et al, 2016;McClellan, 2016;Solomon, 2016;Williams et al, 2016a,b), sponsored by Monsanto and other members of the pesticide industry, as declared in the papers themselves. These reviews focused on the carcinogenicity, genotoxicity of glyphosate and exposures to it, but considered partly the same data and followed the same concept published in a previous risk assessment by the same lead author (Williams et al, 2000).…”

The rise and future of glyphosate and glyphosate‐resistant crops

“…The health issue was reignited in 2015 when the International Agency for Research on Cancer (IARC) published a monograph concluding that glyphosate is ‘probably carcinogenic to humans’ . The US Environmental Protection Agency and others have since concluded that glyphosate is likely not a carcinogen, but the firestorm over its safety continues in both popular press and scientific publications . In addition, concerns are often raised about the safety of glyphosate formulations that contain the original tallow amine ethoxylate ‘Roundup surfactant.’ This surfactant type has known aquatic and eye toxicity issues that are commonly addressed with mandatory application restrictions and requirements for operators to wear personal protective equipment (PPE).…”