Persistence and diffusion behaviour of chlorpyrifos in five different species of vegetables: A comparative analysis

Understanding of pesticide persistence and diffusion on the fresh vegetables are extremely important in food safety and decontamination process. In this study, we examine the persistence and diffusion behaviour of chlorpyrifos pesticide in five different species of vegetables. The chlorpyrifos pesticide was spiked on the vegetable surfaces and the extracted samples from peel and tissues were subjected to Gas Chromatography equipped with a Flame Photometric Detector (GC-FPD). Further, the chlorpyrifos diffusion behaviour was compared with the osmotic potential, shear strength, cuticular chemical profile and microstructure of peel surface of vegetables. The persistence analysis results revealed that chlorpyrifos level was decreased in peel surface and diffusion rate was increased in inner tissue with respect to durations. Within 72 h exposure, chlorpyrifos reached 0.7 cm depth into the inner tissue of vegetables. Significant level of chlorpyrifos diffusion with P ≤ 0.05 was observed in beetroot (2.47%), khon khol (1.46%) and brinjal (0.92%) compared to cucumber and potato. Remarkably, there was no direct linkage between the chlorpyrifos diffusion rate, osmotic potential and toughness of vegetables. In addition, the Gas Chromatography Mass Spectroscopy (GC-MS) and Scanning Electron Microscopy (SEM) analyses revealed that epicuticular surface microstructure and chemical profiles were not correlated with the chlorpyrifos diffusion in all the tested vegetables. The study results concludes that chlorpyrifos diffusion is vegetable species specific and it is highly variable between the species.