Dissipation of spiroxamine residues in open field cucumber and dietary risk assessment

Spiroxamine is one of the most used fungicides in the Mediterranean region, in significant uses such as open field cucumber. Residue trials in the Northern part of Egypt were conducted to investigate the dissipation of spiroxamine (SPX) in cucumbers according to the authorized Good Agricultural Practice (GAP) (1 × 75 g a.i. ha⁻¹ at BBCH 85 to 89) and more critical use patterns. SPX was extracted from cucumbers using a modified QuEChERS protocol and residues were analyzed by liquid chromatography with tandem mass spectrometry (LC–MS/MS). The method was successfully validated with an LOQ of 0.001 mg kg⁻¹. A steep decline of SPX residues in cucumbers fit a first-order decay process with a calculated t_1/2 of approximately 2 days and almost complete degradation (99%) after 14 days. Chronic and acute exposure calculations were performed for cucumbers treated with SPX according to all tested GAPs employing two different approaches. In all cases a health risk after consumption of cucumbers was not identified.