title: Abiotic degradation of glyphosate into aminomethylphosphonic acid in the presence of metals.
abstract: Glyphosate [N-phosphono-methylglycine (PMG)] is the most used herbicide worldwide, particularly since the development of transgenic glyphosate-resistant (GR) crops. Aminomethylphosphonic acid (AMPA) is the main glyphosate metabolite, and it may be responsible for GR crop damage upon PMG application. PMG degradation into AMPA has hitherto been reckoned mainly as a biological process, produced by soil microorganisms (bacteria and fungi) and plants. In this work, we use density functional calculations to identify the vibrational bands of PMG and AMPA in surface-enhanced Raman spectroscopy (SERS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra experiments. SERS shows the presence of AMPA after glyphosate is deposited from aqueous solution on different metallic surfaces. AMPA is also detected in ATR-FTIR experiments when PMG interacts with metallic ions in aqueous solution. These results reveal an abiotic degradation process of glyphosate into AMPA, where metals play a crucial role.
authors.affiliation: Instituto Balseiro, Centro Atómico Bariloche (CNEA), Universidad Nacional de Cuyo , Avenida Exequiel Bustillo 9500, 8400 San Carlos de Bariloche, Argentina.
authors.forename: J
authors.initials: J
authors.lastname: Ascolani Yael
authors.forename: J D
authors.initials: JD
authors.lastname: Fuhr
authors.forename: G A
authors.initials: GA
authors.lastname: Bocan
authors.forename: A
authors.initials: A
authors.lastname: Daza Millone
authors.forename: N
authors.initials: N
authors.lastname: Tognalli
authors.forename: M
authors.initials: M
authors.lastname: Dos Santos Afonso
authors.forename: M L
authors.initials: ML
authors.lastname: Martiarena
mesh_terms: D001673:Biodegradation, Environmental; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism; D007555:Isoxazoles; D008670:Metals / Q000737:chemistry* / Q000378:metabolism; D063065:Organophosphonates / Q000737:chemistry* / Q000378:metabolism; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013777:Tetrazoles; D000097797:Glyphosate
chemical_list: D005998:Glycine; D006540:Herbicides; D007555:Isoxazoles; D008670:Metals; D063065:Organophosphonates; D012989:Soil Pollutants; D013777:Tetrazoles; D000097797:Glyphosate; C418233:2-amino-3-(3-hydrox-5(2-methyl-2H-tetrazol-5-yl)isoxazol-4-yl)propionic acid
keywords: AMPA; abiotic degradation; glyphosate; herbicides