Temporal Trends, Multiple Residue Incidence, and Chronic Health Risk of Pesticides in Egyptian Onions: A Four-Year Market Surveillance

Abstract

This study analyzed 5731 Egyptian onion samples collected from 2021 to 2024 to detect 430 pesticide residues and evaluate occurrence patterns, EU Maximum Residue Limits (MRLs) compliance, multiple residue prevalence, and consumer health implications. The analysis revealed temporal fluctuations in contamination, with residue-free samples ranging from 51.19% (2023) to 75.59% (2022) and MRL exceedances varying from 1.34% (2022) to 8.33% (2023). Throughout 2021-2024, fungicides dominated pesticide residues, declining from 70% to 50%, while insecticides increased from 30% to 40%. Pesticide detection patterns shifted significantly over the study period, with carbendazim decreasing from 20.99% to 2.35%, azoxystrobin fluctuating between 3.86% and 18.78%, and dimethomorph rising to 16.67%, reflecting evolving agricultural practices. Multiple residue occurrence fluctuated dramatically, from 9.76% (2022) to a peak of 30.82% (2023), while single residue occurrence remained more stable, ranging between 14.06% and 22.90%. Several pesticides exceeded EU MRLs, including imazalil, chlorpropham, chlorpyrifos, imidacloprid, and profenofos. Despite these violations, the EFSA PRIMo 3.1 model's chronic risk assessment showed that exposure levels for all population groups remained well below Acceptable Daily Intake (ADI) thresholds, with a maximum %ADI of 2.27% for chlorpyrifos in high-consumption regions.