Regional patterns and food-category contributions to dietary intake of seven elements in China: Evidence from the sixth China total diet study

Total Diet Studies characterize chronic dietary exposure from foods as consumed. We analyzed aggregated data from the Sixth China Total Diet Study (2016-2019) for Pb, Cd, Cr, Hg, As, Cu, and Zn across 24 provincial-level regions and 12 food categories. Regional variability and food-category contributions were summarized, and principal component analysis and Ward.D2 hierarchical clustering were applied to log 10 -transformed, element-standardized total intakes. Absolute food-category-specific intakes were compared across clusters, and food-composite concentrations helped interpret selected differences. Regional variability was greatest for Cr (CV = 95.9%), As (73.7%), and Cd (73.0%) and lowest for Cu and Zn (approximately 24%). Cereals were the leading contributor to Cu in all 24 regions, Zn in 23, Cd in 18, and Pb in 17, whereas the leading contributors to Hg and As varied among cereals, aquatic foods, and vegetables. The first three principal components explained 80.7% of the variance and showed a broad multi-element gradient together with element-specific contrasts. The four clusters were characterized by a Shanxi-specific Cu-Zn pattern, a broad multi-element pattern, a Pb-oriented pattern, and an Hg-oriented pattern. Contribution percentages described intake composition within clusters, whereas absolute food-category-specific intakes identified element-food combinations with intakes above the 24-region mean. Together, these findings provide a regionally resolved understanding of multi-element dietary exposure that cannot be obtained from national mean intakes. They offer an empirical basis for interpreting China TDS results and identifying region-specific element–food combinations that warrant closer attention in future assessments.