Dissipation Dynamics and Risk Assessment of Thiacloprid Residues in Chilli Pepper (Capsicum annuum L.) and Soil using Liquid Chromatography-Tandem Mass Spectrometry

The dissipation of thiacloprid (Alanto 240 SC) in fresh, dry chilli pepper and soil is reported. The residues in fresh and dry chilli peppers reached below the quantitation limit of 0.01 mg kg⁻¹ after 15^th and 21^st d respectively of application of thiacloprid at 63 and 126 g a.i. ha⁻¹. The residue magnified by 1.56 to 1.88 times on sun drying of fresh chilli peppers, necessitating study on its residue dynamics at different processing steps. Half-lives of thiacloprid at lower and higher doses of application were 3.4 and 4.3 d for fresh chilli peppers, and 2.7 and 3.8 d in the case of dry chilli peppers. The corresponding waiting periods were 10.3 and 16.0 d on fresh chilli peppers and 7.7 and 15.9 d in dry chilli peppers. The residue in soil reached below LOQ after 10^th and 15^th day, registering a half-life of 2.49 and 2.52 d respectively at the two doses. The risk assessment showed TMRC values on 0 d at 0.825 and 1.635 μg person⁻¹ d⁻¹ at the lower and higher doses respectively on fresh chilli peppers, whereas dry chilli peppers showed 0.354 and 0.720 μg person⁻¹ d⁻¹. The thiacloprid applied at the lower and higher doses to chilli pepper did not pose any risk to humans, even on the day of application. It can thus be incorporated in integrated management of pest complex in chilli.