Dietary lead exposure from vegetables: A global assessment of contamination patterns and health risks

Lead (Pb) exposure remains a persistent environmental health concern even after the global phase-out of leaded gasoline. This study synthesized 27,780 vegetable Pb concentration records from 71 countries (1981-2023), integrating peer-reviewed literature, the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) Food Safety Collaborative Platform (FOSCOLLAB) database, and national Total Diet Studies under a unified analytical framework. Spatial and temporal patterns of vegetable Pb contamination were characterized before and after leaded gasoline phase-out across four vegetable groups (fruiting, leafy, legumes, and root, tuber, and stem vegetables). Statistical associations between vegetable Pb concentrations and 16 macro-scale environmental and anthropogenic variables were examined using Pearson correlation and multivariable regression. Dietary exposure was assessed using the Margin of Exposure approach with population-specific consumption data. The compiled data revealed a pronounced monitoring imbalance: monitoring records were concentrated in high-income regions, while many low- and middle-income countries were represented mainly by literature-derived data. Post-ban vegetable Pb concentrations remained spatially heterogeneous, with low median values in North America, Western Europe, and Oceania but localized elevated concentrations in parts of Africa, the Middle East, South Asia, and Southeast Asia. Among the macro-scale predictors, PM_2.5 showed the most consistent positive association with vegetable Pb concentrations across all vegetable groups. In the available post-ban dataset, exposure-based assessment identified five countries where the estimated daily intake (EDI) for adults exceeded the adult point-of-departure (POD) value of 1.2 μg·kg^-1·bw·day^-1, and one country where child EDI exceeded the child POD value of 0.6 μg·kg^-1·bw·day^-1. Temporal comparison further showed that concentration reductions did not necessarily translate into proportional reductions in dietary exposure when vegetable consumption patterns changed. These findings support complementing concentration-based standards with exposure-based surveillance that accounts for evolving dietary patterns and highlight the need for strengthened food-contaminant monitoring in underrepresented regions.