Sweet products, subtle residues: neonicotinoid contaminations in commercial honey from Thailand

Environmental pollution with pesticides, including neonicotinoid insecticides, is a major driver of biodiversity loss and raises concerns for both pollinators and human health. As a product of nectar foraging, honey integrates environmental contamination across large spatial scales, making it a valuable sentinel matrix for pesticide exposure. However, systematic data on neonicotinoid residues in commercial honey from tropical ecosystems are currently lacking. Here, we show that neonicotinoid residues are widespread in Thai commercial honey, albeit at levels posing low acute risk to humans and bees. Using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS; limits of quantification 0.25-1 ng g^-1, recoveries 94-117%), residue concentrations of five commonly used neonicotinoid insecticides were quantified in 31 commercial honey samples. Neonicotinoid residues were detected in more than 60% of samples, frequently involving multiple compounds, with concentrations ranging up to 3.11 ng g^-1. Although calculated exposure metrics indicated low acute risks for both human consumers and bees, detected residue concentrations overlapped with levels reported to induce sublethal effects in bees under chronic exposure scenarios. This first broad survey of neonicotinoid residues in Thai commercial honey demonstrates frequent low-level contamination and underscores the need for expanded pesticide monitoring that includes additional hive matrices and pollinator taxa. Such data are essential to better characterize real-world exposure scenarios and to support more sustainable pest and pollinator management in tropical agroecosystems.