CurrentUsed Pesticides in Air and Soil in EasternChina: Occurrence, Spatial-Seasonal Distribution, and Air–SoilExchange

Current used pesticides (CUPs) are extensively used as alternatives for traditional pesticides in the world. In order to investigate the pollution characteristics of CUPs in a large-scale multimedium environment, a comprehensive and comparative study was conducted on occurrence, spatial-seasonal distribution, and air–soil exchange of CUPs across 30° latitude in Eastern China. A total of 72 target CUPs were detected, and 43 CUPs had a detection frequency over 30% in both air and soil samples. Herbicides, fungicides, and organophosphorus insecticides predominantly exhibited volatilization from soil to air, while pyrethroids exhibited deposition from air to soil. In the high-latitude Northeastern China, the air–soil exchange net flux of CUPs was the lowest due to the lower temperature, especially in winter. Along with decreasing latitude and increasing temperature, the air–soil exchange flux increased, which was significantly influenced by cultivation practices and the usage frequency of CUPs. Therefore, the grasshopper effect driven by temperature difference caused further migration and deposition of CUPs toward higher latitude regions. Moreover, the emission fluxes of CUPs to soil exhibited significant variations closely linked to local climatic conditions and types of crops. In summary, this study obtained valuable baseline information for the pollution characteristics and air–soil exchange of CUPs on a large scale, which also provided a better understanding of the environmental fate of CUPs from the migration perspective.