Atmospheric dynamics of glyphosate and AMPA in agricultural areas

The atmospheric dynamics of glyphosate and AMPA was investigated in an agricultural area in the Netherlands over eight weeks following glyphosate application to sandy soil. Airborne sediment was collected every two weeks, at five different heights, and analyzed for glyphosate and AMPA. Results showed that the glyphosate content in the samples was initially high, almost 6000 µg kg^-1 two weeks after application, decreasing to about 2300 µg kg^-1 eight weeks after application. AMPA content showed less variation and fluctuated between 1000 and 1700 µg kg^-1. Airborne concentrations ranged from 0.01 to 1 µg m^-3 for glyphosate and from 0.005 to 0.5 µg m^-3 for AMPA. They showed a clear and systematic decrease with height. Elevated airborne concentrations were measured up to approximately six weeks after application. Horizontal transport flux followed a similar pattern, decreasing with height and remaining elevated up to six weeks after application. Both glyphosate and AMPA were substantially enriched in the fine particle fractions of the soil, with higher enrichment ratios in finer sediments. More than half of the glyphosate and AMPA that was collected in the airborne samples was transported in suspension. The transport pathway was calculated for two days with high emissions and indicated that long-distance travelling of pesticides is a matter of concern. Analysis of the glyphosate and AMPA amounts in the PM10 fraction of the airborne samples suggests that residents in agricultural areas where glyphosate is frequently applied may be at risk of inhalation exposure.