Blood biomarkers of occupational exposure to emamectin benzoate among farmers in Phitsanulok, Thailand

Abstract

Thailand, an agricultural country, relies heavily on pesticide use to sustain crop productivity. Emamectin benzoate (EB1) is one of the most commonly used insecticides for controlling fall armyworms in rice and corn fields; however, limited information exists regarding human exposure among farmers. This study determined EB1 exposure levels among Thai farmers using blood biomarkers. A total of 140 blood samples were collected from 70 farmers after EB1 application during the 2022 rice and corn planting seasons and analyzed for total EB1 and its metabolites using a validated Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) method. Detectable EB1 concentrations were found in 14.3% of rice farmer samples (0.01–9.06 ng/mL) and in 60.0% of corn farmer samples (0.01–18.56 ng/mL). Higher exposure among corn farmers may be attributed to greater application frequency and plant height during spraying. This study provides the first biomarker-based evidence of EB1 exposure among Thai agricultural workers and provides baseline data for future pesticide risk assessment and occupational health guidelines. The potential health effects caused by EB1 exposure should be investigated in future studies.