Multiresidues of pesticides in the particulate matter (PM) emitted by rural soils of the semiarid pampas, Argentina. A potential source of air pollution.

The aim of this work was to evaluate the presence of 40 pesticides in the PM emitted by rural soils of the semiarid region of Argentina. Six agricultural soils for grain production under no till and with high use of pesticides (AG), 5 agricultural soils for forage and grain production under conventional tillage (AFG) and 5 unpaved rural roads (RR) were sampled. The PM was generated using the Easy Dust Generator and it was collected with an electrostatic precipitator. The presence of 20 herbicides, 14 insecticides and 6 fungicides was analyzed in the soil and in the PM. More than 70% of the pesticides analyzed were detected in the soil and in the PM. All agricultural soils and 87% of RR soils showed at least one residue of pesticides. Multiresidues of pesticides were found in the 100% of PM emitted by rural soils. The mean number of pesticides was higher in the PM (7) than in the soil (5). Some pesticides were not detected in the soils but they were detected in the PM (triticonazole, carbofuran, metsulfuron methyl) and vice versa. In general, the concentrations of herbicides were higher in the PM than in the soil, while the concentrations of insecticides and fungicides were lower in the PM than in the soil. These results suggest that the concentrations of pesticide in the PM (inhalable fraction) should be used instead the concentrations of pesticide in the soil to calculate the exposure factor to pesticides by dust inhalation. This study provides the initial evidence of the presence of multiple pesticide residues in PM emitted by rural soils under different land management. Also confirms that the PM is a potential source of air contamination with pesticides. Future studies should be driven to measure the concentrations of pesticides and their dynamics in the PM.