Long-term decomposition and diffusion of glyphosate and glufosinate in soil

The behavior of degradation and diŠusion of phosphorus-containing amino acids, glyphosate and glufosinate, in soil was investigated over a long term of up to 6 months. The herbicides were extracted from the soil under strong alkaline condition and quantiˆed by liquid chromatography-tandem mass spectrometry. DiŠusion and downward penetration were hardly observed for glyphosate, and was observed for about 90 days in summer and about 185 days in winter. For glufosinate, on the other hand, the observation was relatively short at about 10 days, and diŠusion and penetration in soil were slightly observed. In the case when glyphosate or glufosinate is dumped on the ground for criminal purposes, the herbicides could be detected at least for 6 months for glyphosate and 1 month for glufosinate from the surface soil by using the method presented in this paper.