ABSTRACT
Glyphosate (N-[phosphonomethyl] glycine) is the most widely used broad spectrum herbicide able to control weeds in both agricultural and non-agricultural settings. This herbicide has a unique mode of action that inhibits the synthesis of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) enzyme in plants. This mechanism has facilitated the development of glyphosate-resistant (GR) crops. The initial sale of glyphosate was slow but has grown rapidly since the approval was given to cultivate GR crops. It has long been recognized as the safest herbicide on the market, but its overuse and potential threats to the ecosystem and human health have raised concerns about the safety of its application. In 2015, the International Agency for Research on Cancer (IARC) categorized glyphosate as “probably carcinogenic” under Group 2A based on evidence from experimental animal studies, and epidemiological data linking occurrence of cancers in people exposed to this herbicide formulations. The global environmental contamination of glyphosate and its primary metabolite, aminomethylphosphonic acid, has now been well documented. Several incidents have linked non-Hodgkin’s lymphoma to glyphosate use, leading this herbicide becoming a class action chemical. Furthermore, increasing toxicity has been reported in aquatic organisms exposed to glyphosate (acid or salt), particularly when they are mixed with other formulants such as polyethoxylated tallow amine or polyoxyethylene amine. It is time to revisit glyphosate use as perceived by the regulatory agencies and other relevant authorities to ensure the safe use of glyphosate-based formulations or protect the environmental “One Health” ideal. So far, specific technologies have exhibited promising remediation of glyphosate-contaminated soils and water. This chapter presents the sources, fate, behaviors, toxicology, and potential remediation techniques of glyphosate and its metabolites, revealing that the detection of residual glyphosate is crucial for the remediation of glyphosate-contaminated sites.
