Glyphosate runoff and its occurrence in rainwater and subsurface soil in the nearby area of agricultural fields in Argentina

LEONARDO LUPI ; FRANCISCO BEDMAR; MARINO PURICELLI; DAMI
AN MARINO; VIRGINIA C. APARICIO, JOSE LUIS COSTA AND DANIEL GIMÉNEZ; DANIEL WUNDERLIN; KARINA S.B. MIGLIORANZA

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2019

0045-6535

Glyphosate-based products are among the most important herbicides applied to enhance the productionof food commodities, leading to the worldwide spread of this herbicide. The main goal of this work wasto evaluate the off-site transport of glyphosate in a runoff experiment. A micro-plot experiment wasconducted to assess the retention, leaching and runoff of glyphosate under rainfall simulation. Glyphosatelosses due to spray drift were estimated. Concentrations of glyphosate and AMPA were determinedin rainwater and subsurface soil from agricultural and riparian zones. Analyses were performed withUHPLC-MS/MS. Experimental results demonstrated that 88.1% of the applied glyphosate was retained inthe surface soil layer (0e9 cm). Glyphosate leaching was negligible compared to its runoff (3.9%) andspray drift (6.9%). Thus, the risk of groundwater pollution would be lower in comparison to that of bothsurface waters and rainwater. Moreover, under field conditions, glyphosate and AMPA were detected in52% of the rainwater samples and glyphosate was detected up to 1m in both soil profiles. Although theexperimental application was made with hand-held knapsack under low wind condition to minimizeglyphosate aerial dispersion, the spray drift was the main source of glyphosate off-site transport,degrading air quality and rainwater for human consumption. The balance among spray drift, runoff a soil absorption of glyphosate when it was sprayed close to the soil surface (hand held equipment),demonstrated the importance of spray drift in mass balance studies during runoff and leaching experimentswith glyphosate.