Inhalation Exposure to Airborne Prothioconazole Caused by Unmanned Aerial Vehicles Application and Potential Lung Health Effects

The use of unmanned aerial vehicle (UAV) has greatly improved pesticide effectiveness and control efficiency; however, the risk of inhalation exposure to pesticides caused by spray drift requires urgent attention. This study is the first to investigate residue distribution and inhalation exposure risk of airborne prothioconazole and its metabolite prothioconazole-desthio during UAV application. The maximum detected unit exposure of prothioconazole and prothioconazole-desthio in airborne particulate matter was 0.40 and 20.09 ng/m³, respectively. For exposure risk assessment, in vivo inhalation bioavailability (BA_{in vivo}) was incorporated to adjust the inhalation exposure level, and the corresponding values measured were 37.58 and 73.99%, respectively. Moreover, we observed pesticide accumulation in rat lungs and its cause of histological damage via oxidative stress following 10-day exposure. The margin of exposure for propiconazole and prothioconazole-desthio was calculated to be within an acceptable level; however, the values might be overestimated by 40 and 70% without considering inhalation bioavailability.