Analysis of honey bee exposure to multiple pesticide residues in the hive environment

Since the loss of honeybees in hives could have a greater impact on colony health than those of their foraging bees, it is imperative to know beehives' pesticide exposure via oral ingestion of contaminated in-hive matrices. Here, a 4-year monitoring survey of 64 pesticide residues in pollen, nectar and related beehive matrices (bee-bread and honey) from China's main honey producing areas was carried out using a modified version of the QuEChERS multi-residue method. The results showed that 93.6% of pollen, 81.5% of nectar, 96.6% of beebread, and 49.3% of honey containing at least one target pesticide were detected either at or above the method detection limits (MDLs), respectively, with up to 19 pesticides found per sample. Carbendazim was the most frequently de-tected pesticide (present in >85% of the samples), and pyrethroids were also abundant (median concentration = 134.3-279.0 mu g/kg). The transfer of pesticides from the environment into the beehive was shown, but the pesti-cide transference ratio may be affected by complex factors. Although the overall risk to colony health from pes-ticides appears to be at an acceptable level, the hazard quotient/hazard index (HQ/HI) value revealed that pyrethroids were clearly the most influential contributor, accounting for up to 45% of HI. Collectively, these em-pirical findings provide further insights into the extent of contamination caused by agricultural pesticide use on honeybee colonies. (c) 2021 Published by Elsevier B.V.

Automated summary

A 4-year monitoring survey in China's main honey producing areas revealed that a high percentage of pollen, nectar, beebread, and honey contained detectable levels of pesticides, with pyrethroids being the most influential contributor to potential hazards for honeybee colonies. The study provides insights into the extent of contamination caused by agricultural pesticide use on honeybee colonies.