Method development for the determination of neurotoxic insecticides in bees and bee products

MICHLIG, MELINA PAOLA; DEMONTE, LUISINA DELMA; MAGNI, FLORENCIA VALENTINA; RAATS, DAIANA; BRASCA, ROMINA; REPETTI, MARÍA ROSA

Panamá

Workshop; 9TH Latin American Pesticide Residue Workshop (LAPRW); 2023

Ministerio de Desarrollo Agropecuario de Panamá (MIDA)

Among neurotoxic insecticides, stands out the neonicotinoid family because they are widely applied in plant and animal health to control sucking insects. Seven active compounds of this family are registered (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, thiacloprid and thiamethoxam) for a varied set of crops in Argentina. However, due to their systemic properties, several studies reported their translocation to the nectar and pollen of treated plants, posing a potential risk to pollinator insects. Nitro-substituted neonicotinoids such as imidacloprid, thiamethoxam and clothianidin are particularly concerned because they are more toxic to honey bees than cyano-substituted derivatives.This presentation will approach the development of analytical methodologies, using univariate and multivariate strategies, to determine neonicotinoids in beehive materials. Residue levels were determined by liquid chromatography coupled to mass spectrometry (UHPLC-MS/MS). Firstly, the developed methodologies were applied in two trials; the analysis of sunflowers treated with imidacloprid, and in hives surrounded by a soybean field. As both studies evidenced the presence of imidacloprid in pollen and nectar, and likewise knowing that it is the most common neonicotinoid used in South America, the behavior of colonies of honey bees artificially fed with this insecticide was evaluated. For this, 30 beehives were displayed in a common field area and separated into 5 groups of 6 hives. To each group, different imidacloprid concentrations were applied once a week during 7 weeks (500 mL per hive of sucrose solutions containing 0, 15, 30, 120 and 240 µg kg-1). These doses were selected in concordance with concentrations found in pollen and nectar, and in order to simulate long-term exposure with sublethal concentrations of imidacloprid. It was found that the administered doses did not cause immediate colony death and that a large percentage of the supplied imidacloprid was stored in the honey. Based on these results, the determination of neonicotinoids in 151 honey samples from apiaries located in areas of intensive livestock and agricultural production in Argentina was carried out. The presence of three of the target analytes was determined in the honey samples, indicating one more time that honey bee colonies were exposed to neonicotinoids, especially imidacloprid and thiamethoxam. From public health point of view, the observed levels of neonicotinoid residues in honey did not pose a serious health risk to the consumers.The occurrence studies carried out together with the pollinator behavior tests, allowed inferring the impact of the current agricultural production systems models on bees in the central region of Argentina. This knowledge is essential to guide strategic pesticide regulatory measures to ensure the conservation of these important organisms.