Glyphosate behavior at soil and mineral–water interfaces

• Published in: Environmental pollution (1987) Vol. 153; no. 1; pp. 53 - 59
• Main Authors: Pessagno, Romina C., Torres Sánchez, Rosa M., dos Santos Afonso, María
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01-05-2008; Elsevier
• Subjects: Adsorption; Applied sciences; Argentina; Bentonite; biodegradability; Biological and physicochemical properties of pollutants. Interaction in the soil; chelation; chemical concentration; clay soils; Clays; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Glycine - analogs & derivatives; Glycine - chemistry; Glyphosate; herbicide residues; Herbicides - chemistry; Humic Substances; Hydrogen-Ion Concentration; hydrologic models; Iron; kinetics; mineral content; organic matter; Pollution; Pollution, environment geology; prediction; probabilistic models; Soil and sediments pollution; Soil Pollutants - chemistry; soil pollution; soil properties; soil types; soil water potential; Soils; sorption isotherms; Surface complexes; surface interactions; thermodynamics; Water Pollutants - chemistry; Argentina; Clays; Surface complexes; Soils; Adsorption; Glyphosate; Clay; Surface complex; Agricultural chemical product; Soil water interface; Montmorillonite; Pollutant behavior; Pesticides; Property of soil; Systemic; Soil pollution; Herbicide; Edaphic factor; Aminoacid; Organic compounds
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2007.12.025

Adsorption isotherms and surface coverage of glyphosate,
N-phosphonomethylglycine (PMG), in aqueous suspensions of three Argentine soils with different mineralogical composition were measured as a function of PMG concentration and pH. Zeta potential curves for PMG/soils system were also determined. Montmorillonite and soil sample surface charges were negative and increased as the amount of adsorbed PMG increased, showing that the surface complexes are more negative than those formed during the surface protonation. PMG adsorption on soils were described using Langmuir isotherms and the affinity constants, and the maximum surface coverage was estimated at pH 4 and 7 using a two-term Langmuir isotherm, the mineralogical composition percentages, and maximum surface coverage and Langmuir constants for pure minerals. The influence of organic matter (OM) and iron content of soils on the PMG adsorption was evaluated. The surface coverage of PMG decreased when the OM and iron content decreased for minerals and soils.
Adsorption isotherms, surface coverage and zeta potential curves of glyphosate in aqueous suspensions of montmorillonite and three Argentine soils were measured as a function of PMG concentration and pH.