Use of passive sampling and high-resolution mass spectrometry for screening emerging pesticides of concern within surface waters

This study addresses the challenges for environmental monitoring of the increasing number of pesticides used. A novel approach for regional monitoring is proposed, utilizing local pesticide registration data, non-target aquatic organism toxicity, and non-routine pesticides. A suspect screening method, combining passive sampling and high-resolution mass spectrometry was developed. In Greater Melbourne, Australia, 181 priority pesticides were investigated across 32 waterway sites with diverse land uses. Liquid chromatography and quadrupole-time-of-flight mass spectrometry were employed for pesticide detection in a data-independent acquisition mode. Of the 181 pesticides, 21 were tentatively detected at 22 sites, with 5 confirmed using certified reference materials. Notably, newly emerging pesticides not previously identified in Australian waterways were detected. Confirming priority pesticides before routine screening is vital for monitoring program efficiency. The study demonstrates the efficacy of combining regional screening and broad-field sampling with suspect screening using high-resolution mass spectrometry. This approach enhances understanding of emerging pesticide levels, aiding in prioritizing compounds for routine screening programs, thus providing a comprehensive strategy for updating pesticide monitoring in specific regions.