Determination of neonicotinoids in honey and pollen with probabilistic risk assessment for humans and pollinators in South Korea.

Neonicotinoid insecticides have been identified as significant contributors to the decline of pollinators. To evaluate potential exposure of pollinators to neonicotinoids in South Korea, 79 honey samples and 27 pollen samples were obtained from agricultural, mountain, and urban areas. These samples were analyzed for 17 compounds, including neonicotinoids and their metabolites using liquid chromatography coupled with mass spectrometry. The result revealed that all honey and pollen samples contained at least one target compound, indicating widespread contamination. Among honey samples, acetamiprid (82%), dinotefuran (58%), and flonicamid (52%) were the most frequently detected, while pollen samples showed high detection frequencies of acetamiprid (96%), dinotefuran (96%) and 5-hydroxy-imidacloprid (85%). Honey samples from agricultural areas showed the highest concentrations of flonicamid (0.33-190 ng/g), acetamiprid (0.04-152 ng/g), and imidacloprid (0.24-27.8 ng/g) compared to samples from mountainous and urban areas. Pollen samples exhibited different distribution patterns, with acetamiprid (0.2-260 ng/g) reaching the highest concentration in samples from mountainous areas, while 5-hydroxy-imidacloprid (6.4-94.3 ng/g) was highest in samples from agricultural areas. Probabilistic risk assessment using hazard quotients (HQ) indicated that neonicotinoids in honey remained within acceptable limits for human health, except for the potential risk to children exposed to thiacloprid. However, the risk quotient (RQ) values exceeded 1 for clothianidin and imidacloprid, suggesting significant risks to bees. These findings demonstrate the widespread presence of neonicotinoids and their metabolites in honey and pollen with a complex spatial distribution influenced by agricultural practices and environmental factors.