Dinotefuran Residues and their Dissipation in Chilli Pepper (Capsicum annuum L.) and Soil and their Risk Assessment

Abstract

The results of a study conducted to assess the degradation pattern and risk assessment of dinotefuran in chilli pepper and soil using LC-ESI-MS/MS are reported. A modified “QuEChERS” method for the extraction and clean up giving acceptable recovery value for all the three matrices was used. Residues in fresh chilli peppers reached below the limit of quantitation, (LOQ 0.01 mg kg-1) on 15th and 21st d of application of dinotefuran at 27.5 and 55 g a.i. ha−1 respectively whereas in dried chilli peppers, these reached below 0.01 mg kg−1 on the 21st and 25th d. The residues got magnified by 2.69 to 3.00 times during sun drying of fresh chilli peppers, necessitating detailed study on its dynamics during different processing steps. Half-live of dinotefuran at the standard and double doses were 2.1 and 2.4 d for fresh chilli peppers, and 2.3 and 2.6 d respectively in the dried chilli peppers. The corresponding calculated waiting periods were 1.34 and 3.45 d for fresh chilli peppers. The residue in soil reached below the LOQ on the 10th d, registering a half-life of 1.86 and 1.43 d at the standard and the double doses respectively. The risk assessment showed that the the theoretical maximum residue contribution (TMRC) in fresh chilli peppers on 0 d were 3.024 and 5.739 μg person−1 d−1 at the standard and the double doses respectively. The residues present in the food were considered safe since the TMRC value was lower than the maximum permissible intake (MPI). Therefore, the dinotefuran applied at the standard and the double doses in chilli pepper did not pose any risk to humans, even on the day of its application. It can be incorporated as one of the insecticides in integrated management of pest complex in chilli under the humid climatic conditions.