Pesticide residues and transformation products in Greek honey, pollen andbeebread

Abstract

Apiculture products, to an extent, are considered as environmental pollution markers, since they tend to accumulate a plethora of contaminants. The latter come in contact or enter in bees during nectar and pollen collection and transferred inside the beehives. In addition, residual prevalence in honey, and beebread also reflects the chemical treatments that take place inside the beehives in order to mainly control the parasitic mite of Varroa destructor. In this context, during the period of 2014-2018, 109 samples of honey, pollen, and beebread (63 honey and 46 pollen and beebread), including samples originated also from colonies in which honeybees’ death incidents were recorded, were sent by authorities and individuals in Benaki Phytopathological Institute for the determination of pesticides and their transformation products. More than 130 analytes were investigated by applying two multi-residue methods (an HPLC-ESI-MS/MS and a GC-MS/MS), based on modified QuEChERS methodology using for clean-up Z-Sep, PSA, and C18 materials. In particular, the two analytical methods applied were validated according to the SANTE/11945/2015 and 11813/2017 guidelines. More specifically, the recoveries observed for the majority of the analytes ranged between 68 and 117%, while the relative standard deviations were below 19%. The calculated limits of quantification (LOQs) ranged from 1 to 10 ng/g depending on the analyte. Other parameters, such as linearity, selectivity, precision and matrix effect were also validated. Until the end of 2018, 37 determinations were registered in honey, resulting in a 38% of positive to at least one active substance in honey samples (16 active substances and transformation products were detected in total). The detected concentrations of pesticides and their transformation products ranged between 1.3 and 785 ng/g honey. In some cases, maximum residue limits (MRLs) violations were evidenced. Coumaphos, imidacloprid, acetamiprid, the transformation products of amitraz, DMF-DMPF, tau-fluvalinate and in limited cases metabolites of imidacloprid and coumaphos (its oxon metabolite), were the most predominant compounds detected in honey, while several pyrethroids such as λ-cyhalothrin, cypermethrin, and cyfluthrin were also found. In several honey samples, more than one active substance was detected, while the most common combination comprised of coumaphos, imidacloprid, and DMF. In pollen, and beebread more active substances were identified (21) with a comparative number of determinations (including a higher number of fungicides detected compared to honey), and a higher proportion of positive samples (65%). Overall, this work aims to provide an overview of the current situation of pesticides and transformation products occurrence in honey, pollen, and beebread during the period of 2014-2018 in Greece. 3.3 Impact of the use of plant protection products harmful to bees on bee colonies during spring: Results of a monitoring programme in apple orchards in South Tyrol (2014-2017) Benjamin Mair, Manfred Wolf Versuchszentrum Laimburg, Laimburg 6, 39051 Pfatten (BZ), Italien E-Mail: benjamin.mair@laimburg.it, Manfred.wolf@laimburg.it DOI 10.5073/jka.2020.465.025