Flonicamid and imidacloprid are insecticides that are commonly used for the protection of many annual open field crops, such as beans, against insects. Residues of these insecticides in the consumable product above the acceptable limits can cause health concerns or trade barriers; thus, the dissipation behaviour and the consumer risk assessment of flonicamid and imidacloprid residues in open field green beans were investigated. The initial concentrations were found to be 0.44 and 0.99 mg kg(-1). The decline of residues followed in both cases the first-order kinetics model with half-lives of 2.3 (r(2) 0.912) and 2.1 (r(2) 0.977) days, for flonicamid and imidacloprid, respectively, while degraded almost completely after 14 days if applied according to the authorised patterns. The dietary risk assessment performed using the hazard quotient (RQ) and the EFSA PRIMo model showed no concern to consumer health with exposure values <2% of the acceptable daily intake (ADI) and <22% of the acute reference dose (ARfD) of each compound. In conclusion, the investigation of the dissipation behaviour of these compounds in green bean provides useful information to ensure safe pre-harvest intervals, acceptable dietary exposure and compliance with good agricultural practices and maximum residue levels.

Determination and dissipation kinetics of pymetrozine and spirotetramat in green bean were studied using a QuEChERS method coupled to high-performance liquid chromatography-tandem mass spectrometry. Pymetrozine recoveries ranged between 88.4–93.7%, with relative standard deviation (RSD) of 5.5–14.4%. For spirotetramat the recoveries ranged between 91.7–103.4%, and the RSD were in the range of 3.2 to 12.4%. The limits of quantification (LOQs) were 0.01 mg/kg and 0.005 mg/kg for pymetrozine and spirotetramat, respectively. The developed analytical method was used to study the degradation rates of pymetrozine and spirotetramat in green bean grown in open field. Results showed that pymetrozine and spirotetramat followed the first-order kinetics model with half-lives of 3.3 days and 4.2 days, respectively. Furthermore, risk assessment was carried out which showed that, the chronic risk quotient (RQc) values for pymetrozine and spirotetramat were much lower than 100%. The present results indicated that the health risks posed for consumers by the pymetrozine and spirotetramat residues were negligible at the recommended dosages.

The dissipation behaviour and the consumer risk assessment of spitotetramat, flonicamid, imidacloprid and pymetrozine in open field strawberries were studied. Insecticides were applied at the authorised levels and the more critical good agricultural practice regimes (GAP). The initial concentrations varied from 0.069 to 1.75 mg kg(-1) depending on the compound, while the dissipation half-lives and terminal residues, 14 days from the last applications, were similar. After application according to the authorised pattern the half-lives were 2.8 days for flonicamid and 3.2 days for spitotetramat, imidacloprid and pymetrozine. The dietary risk assessment, performed using the hazard quotient and the EFSA PRIMo model showed no concern to consumer health with exposure values <2% of the acceptable daily intake (ADI) and <32% of the acute reference dose (ARfD) of each compound.