Above the Fields: Tracking Pesticides by Drone Mounted Thermal Desorption

Containments of emerging concerns (CECs) are environmental pollutants that may pose significant risks to both ecosystems and human health. Pesticides are CECs due to their widespread use, persistence in the environment, and link to human disease. Pesticides are commonly sprayed on crops to protect them from damage resulting in increased food production. This study investigates the air quality above a corn field and bean field in Clinton County, Illinois utilizing thermal desorption (TD) coupled with gas chromatography tandem mass spectrometry (GC-MS/MS). The instrument used in the analysis was a Shimadzu GCMS-TQ8050 NX that is equipped with a Shimadzu TD-30. Based on the pesticide formula sprayed over the fields, the three pesticides analyzed for were atrazine, acetochlor, and lambda-cyhalothrin. Air samples were collected by flying a drone over the fields with three TD tubes attached using a 3D printed mount and zip ties for approximately 10 minutes at heights of 3, 10, and 20 meters. Air samples were collected prior to pesticide application, one-week post-application, and one-month post-application. Atrazine and acetochlor were detected above the corn field at all three sampling heights one week after application, while both compounds were only detected at the 3-meter height above the adjacent bean field. None of the target analytes were detected in samples collected before spraying or one-month post-application. Quantitative results showed atrazine concentrations ranging from 0.456 to 0.499 ng/L above the corn field, while acetochlor reached a maximum concentration of 0.902 ng/L at 10 meters. Lambda-cyhalothrin was not detected in any air samples. These findings highlight the presence of airborne pesticides following agricultural application.