Neonicotinoid Insecticide Residues in Honey

Neonicotinoid insecticides belong to the most important pesticides in the protection of agricultural crops. Honeybees may come into contact with them as a consequence of their wide-spread application. The first matter of investigation of this thesis dealt with a possible exposure route of honeybees towards neonicotinoid insecticides, focusing on the detection and quantification of neonicotinoids in the guttation liquid of maize plants cultivated from neonicotinoid-treated seeds using LC-MS/MS. The investigated neonicotinoids clothianidin, imidacloprid and thiamethoxam were detectable in the guttation liquid in considerable quantities in the ppm range. In the context of the possible exposure of honeybees to neonicotinoid insecticides these pesticides might be transferred into honey which represents a food with very high purity demands by consumers. In this context the main objective of this thesis was the development and validation of an analytical method for the simultaneous determination of neonicotinoid insecticides in honey and the subsequent analysis of Austrian honey and nectar samples.

A total of eight neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) and four metabolites (IM 2-1, TFNAAM, TZMU and TZNG) were included in the multi-residue method. The final method involved a sample preparation procedure based on acetonitrile extraction and subsequent clean-up by dispersive solid-phase extraction followed by detection and quantification using LC-MS/MS. Three neonicotinoid insecticides were detectable in the analysed honey samples: 18 out of 41 samples contained thiacloprid, two samples acetamiprid and one sample traces of thiamethoxam. Honey samples from beehives with reported losses of honeybees proved to be contaminated more often and with higher amounts of thiacloprid than standard monitoring samples. Further, flower honey samples contained on average higher thiacloprid residues than forest honey samples. Nine out of eleven nectar samples contained thiacloprid. A correlation of positive samples with areas of high proportion of maize and rape cultivation could not be established.

Source: MSc Thesis Gina Tanner (Diplomarbeit) Vienna University: Development of a Method for the Analysis of Neonicotinoid Insecticide Residues in Honey using LC-MS/MS and Investigations of Neonicotinoid Insecticides in Matrices of Importance in Apiculture

One of the findings:
"In May 2008 the CVUA Stuttgart analysed 24 honey samples from Southern Germany with focus on the following neonicotinoid insecticides: acetamiprid, clothianidin, imidacloprid, nitenpyram, thiacloprid and thiamethoxam. In 75 % of the samples, thiacloprid was detected in concentrations ranging from 2 to 110 μg/kg. Traces of thiamethoxam (1 μg/kg) were found in one honey sample while no other neonicotinoids insecticides were detected in the samples (Chemisches und Veterinäruntersuchungsamt Stuttgart 2008a). In June to August 2008 the CVUA Stuttgart analysed another 67 honey samples for pesticide residues. Only 18 % of them contained pesticide residues. Thiacloprid was found in four honey samples at concentrations of 7 to 45 μg/kg (Chemisches und Veterinäruntersuchungsamt Stuttgart 2008b). Further, the content of clothianidin was analysed in 65 honey samples from areas affected by honeybee colony losses in Southern Germany. In seven samples clothianidin was detected in the range of 1.1 to 2.3 μg/kg."