Enrichment and Source Apportionment of Potentially Toxic Elements in Human Scalp Hair from the “Tin Capital” Gejiu and Surrounding Cities, China

This study investigated seven potentially toxic elements (PTEs) (Cd, Cr, As, Hg, Cu, Pb, and Zn) in human scalp hair (n = 100) from random residents near a renowned polymetallic mining area in southwest China. Concentrations ranged from 0.002–0.610 µg/g (Cd), 0.000–0.558 (Cr), 0.050–5.490 (As), 0.071–2.750 (Hg), 3.150–27.200 (Cu), 0.000–804.000 (Pb), and 78.700–1360.000 (Zn). Levels of As, Hg, Pb, and Zn were generally elevated compared to international reference values and typical mining sites. Statistical analysis showed no significant overall influence of age or gender on PTEs levels. However, Hg tended to accumulate in the elderly, while Pb was higher in children. Females had significantly higher Cd and Zn levels. Spearman correlations revealed strong positive associations between Cd–Pb and Pb–As in both sexes, and negative correlations between Zn–As and Zn–Pb in females, suggesting common sources and possible antagonistic interactions. Principal component analysis (KMO = 0.578; total variance explained = 67.37%) identified three main sources: PC1 (Cd, Pb, As) attributed to mining and smelting; PC2 (Hg) to coal combustion; and PC3 (Zn, Cu) to endogenous factors. Cr originated from mixed industrial and personal sources. Multiple linear regression showed that industrial output accounted for 26.3% of PTE variation, with Cd (B = 0.043) and Pb (B = 0.102) positively, and Hg (B = − 0.019) negatively correlated with production levels. These findings highlight complex, multisource PTEs exposure in study area, offering scientific evidence for environmental management and public health policy.