Field-realistic exposure to pesticide residues in beehive pollen and honey and the associated risk to honeybees.

BACKGROUND Honeybees, as the most important pollinators, can be affected by pesticides while foraging for nectar and pollen. Previous studies have shown that some pesticides can be found in pollen and nectar in realistic samples. However, the actual exposure characteristics of bees and the core sources of pesticides in the karst landform of Guizhou remain unknown at present. In this study, environmental DNA analysis was performed on bee pollen to examine its plant sources. Furthermore, the types and concentrations of pesticides in honey and bee pollen to which the associated bees were exposed were determined using the optimized QuEChERS extraction method combined with ultraperformance liquid chromatography-tandem mass spectrometry. In addition, the risks posed by the detected pesticides to the bees were assessed. RESULTS Results showed that spring beehive pollen mainly originated from agricultural crops, while autumn beehive pollen primarily originated from wild plants. Among the 427 samples of honey and bee pollen. Twenty-five types of pesticides were identified, including thiamethoxam, difenoconazole, and chlorantraniliprole, which were the most frequently detected pesticides in the samples. The overall pesticide detection rate for the samples was 54.8%. The HQ and ΣHQ values of the detected pesticides for bees were less than 1.0. CONCLUSION A higher number of pesticides was detected in the spring samples (24 pesticides) than in the autumn samples (seven pesticides), implying that the bees encounter greater challenges in spring and summer than in autumn and winter. The residual levels of these pesticides posed acceptable exposure risk levels to the bees. © 2025 Society of Chemical Industry.