Degradation of glyphosate in the aquatic environment: An enzymic kinetic model that takes into account microbial degradation of both free and colloidal (or sediment) particle adsorbed glyphosate

Abstract

The kinetics of the degradation of the herbicide glyphosate in distilled water and river water containing river sediment were investigated over a period of 12 days. No appreciable degradation of glyphosate was observed in distilled water, while rapid degradation occurred in the river water plus sediment from the outset, suggesting that the degradation is mainly microbial. An immediate 35% loss from solution of glyphosate due to adsorption to suspended sediment particles and deposition to the bottom sediment was observed in the river water plus sediment experiment. Subsequently, two linear rates of degradationwere observed in the water phase of this experiment: an initial rapid degradation followed by a slower breakdown