Residue dynamics, decontamination, and dietary risk assessment of pyriproxyfen and fenpropathrin in okra fruits

Abstract

AbstractSumiprempt containing Pyriproxyfen and fenpropathrin insecticides is used for pest control in okra crop. Pyriproxyfen can disrupt endocrine function, while fenpropathrin disrupts voltage-gated sodium channels in neurons. Based on their health risk to consumers and impact on environmental deposition, an experiment under field was planned to evaluate deposition, decontamination and related dietary risks. A methodology was developed and validated to identify and quantify the pyriproxyfen + fenpropathrin residues, extracted via QuEChERS method using GC-MS/MS. The foliar application of ready-mix formulation (Pyriproxyfen 5% + Fenpropathrin 15% EC) @ 750 gm mL−1 ha−1 and 1,500 gm mL−1 ha−1 leads average initial deposition pyriproxyfen 5% (0.359, 0.584 ppm) and fenpropathrin (0.643, 1.005 ppm) at respective doses. Residues reached below limit of quantification (0.01 ppm) on 15th and 20th day for pyriproxyfen and 10th and 15th day for fenpropathanin at the recommended and double the recommended doses, respectively. Dissipation followed the first-order kinetics with half-life value ranged in between 1.79–1.84 (pyriproxyfen) and 2.27–2.31 days (fenpropathrin) at the respective doses. The pre-harvest interval of 12 days was recommended for safe consumption of okra fruit. Even though all the decontamination treatments were successful in lowering the residues of both chemicals to substantial levels, washing followed by boiling was found to be the most effective treatment for reducing the residues. The risk quotient values were less than 0.01, implying that pyriproxyfen and fenpropathrin offer no dietary risk to consumers.