Chromatographic determination of monoterpenes and other acaricides in honeybees: Prevalence and possible synergies

Abstract

In this study, the first targeted GC–MS/MS method for the detection and quantification of monoterpenic phenols, thymol and carvacrol in honeybees, employing a simplified sample preparation protocol, using ethyl acetate as the extraction solvent, is reported. The method was then applied to honeybees' samples after reported death incidents to evaluate the levels of the afore mentioned compounds in the course of 2015 early 2017. In parallel, other regularly used acaricides, namely amitaz, tau-fluvalinate, and coumaphos were also monitored using an LC-ESI-MS/MS multiresidue method based on modified QuEChERS technique. Breakdown products of amitraz; DMF and DMPF and coumaphos oxon were also investigated. The predominant acaricides detected were coumaphos, thymol, metabolites DMF and DMPF, and in less extent tau-fluvalinate, with concentrations for compounds varying from the low ng/g scale up to approximately 60,000ng/g bee body weight. The highest concentrations were observed for coumaphos and thymol. Preliminary risk assessment using hazard quotient (HQ) as the criterion, showed negligible risk from acaricides as individual components of bees. However, potential synergistic effects between acaricides or acaricides and other pollutants should not be disregarded.