The fate of acetamiprid and its degradation during long-term storage of honey

Acetamiprid (ATP) is a neonicotinoid widely used in agriculture, which is less toxic to honeybees and is transported into the hives via the contaminated nectar and pollen as well as physical contact. Although ATP degrades in animal systems mainly through <i>N</i>-desmethylacetamiprid (IM-2-1), it is degraded in honey of different origins mainly through (E)-<i>N²-</i>carbamoyl-)-<i>N¹-</i>[6-chloro-3-pyridyl)methyl])-<i>N¹-</i>methylacetamidine (IM-1-2). The decomposition of ATP in honey has been followed for storage times up to 180 days at 20°C, 30°C and 40°C to represent geographical regions with different temperatures. Subsequent degradation of IM-1-2 occurred and IM-1-4 was detected as a degradation product of IM-1-2. The apparent decomposition rate constants and half-lives of ATP in honey were determined. ATP degradation to IM-1-2 was faster in honey than the rates observed in aqueous solutions of pH 3.0–5.0. In order to follow actual ATP contamination in honey, IM-1-2 analysis is proposed to be carried out instead of the analyses of ATP and IM-2-1 for safety determination to ensure application of Good Agricultural Practice and to maintain a healthy environment.