Transport of trifluralin on wind-eroded sediment

Abstract

Wind erosion is one of the major forms of soil degradation on the Canadian prairies. Particulate matter emanating from agricultural soil can be transported long distances in the atmosphere and, if the soil has significant clay content, would contain particles less than 2 μm in diameter. Particles of this size range have been associated with respiratory health effects in humans and if they have pesticides associated with them the risk of health effects may be increased. A field experiment was conducted near Regina, Saskatchewan, to determine the trifluralin (2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline) content in wind-eroded sediment from a soil-incorporated application of the herbicide into Regina heavy (71%) clay soil. Three wind erosion events were monitored in which the total estimated soil loss was 62.4 Mg ha-1. The concentration of trifluralin in the winderoded sediment did not show a consistently significant increase with sampler height (10 to 100 cm) and, by implication, decreasing sediment particle size. The concentration of trifluralin in the wind-eroded sediment was lower than that in the incorporation layer and in the surface soil (upper 0.5 to 1 cm). The overall wind erosion loss of trifluralin, as a percent of the amount applied, during three erosion events was 1.4%. The results of this study indicate that human exposure to atmospheric particulate matter, especially in agricultural areas, may simultaneously involve exposure to pesticides. Key words: Trifluralin, wind erosion, wind-eroded sediment, heavy clay