Pesticide detection in managed honey bee colony resources throughout the island of Ireland

  • Marcela Alexandra Díaz Rivadeneira (Student)

Student thesis: Master's Thesis


Multiple factors, including the application of pesticides in agriculture and veterinary in-hive products, play a role in the decline of wild pollinators and managed bees. Pesticide exposure has been reported as a key factor in managed honey bee colony losses in particular. Pesticides can accumulate in pollen and nectar of treated and untreated flowers, soil, and waterways, and can subsequently be transported back to colonies by foraging honey bee workers and end up in colony resources and individuals, such as wax, food supplies, bees, and brood. It has been shown that systemic pesticides such as neonicotinoids, are responsible for physiological, functional, and immunological damage in bees. However, the level of pesticides that bees are exposed to in the environment and in the resources inside their colonies has not been characterised in several key beekeeping regions, including the island of Ireland which is home to more than 50 beekeeping associations. Therefore, this thesis aims to help fill this gap by identifying the level of pesticides that managed honey bees are exposed to in their colony resources throughout the island of Ireland. Honey and pollen samples were collected by beekeepers from their colonies throughout the island, and pesticide levels in these samples were determined using liquid and gas chromatography-tandem mass spectrometry. Pesticides were extracted from samples using the Dutch mini-Luke extraction method. Importantly, here the Dutch mini-Luke method was optimised for small samples (5 grams of sample and 10ml of solvents), which is a common sample size for pollen samples in particular, and validated for the detection of pesticides in honey and pollen samples (Chapter 1). In a second step, the optimised mini-Luke technique was utilised to investigate the levels of pesticides honey bees are exposed to in their colonies in different apiaries throughout the island of Ireland (Chapter 2). Possible sources of contamination and the Maximum Residue Levels (MRLs) for the compounds detected are determined and discussed. Fifteen percent of all samples from throughout the island were found to be positive for pesticides. Three insecticides-acaricides were detected in most of the positive samples (85%). The insecticide Propargite was detected in honey and pollen, and the acaricides for Varroa control, Coumaphos and Fluvalinate-Tau, were found in pollen. The pesticide extraction method optimised here, in combination with the analysis methods, provides a key tool for detecting pesticides in beekeeping resources, and for detecting the level of agrochemicals honey bees are exposed to inside the hive and in the greater environment.
Date of Award14 Mar 2022
Original languageEnglish
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorJulia Catherine Jones (Supervisor)


  • Pesticide detection
  • Miniaturisation method
  • Honey
  • Pollen
  • Insecticide


  • Mestrado em Microbiologia Aplicada

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