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.