Selenium and toxic metals in human hair of the Dashan Region, China: Concentrations, sources, and antagonism effect.

The Dashan Region was a Se-rich region of China. In this study, 131 residents' human hair samples were collected. The concentrations of Se and toxic metals were analyzed, and the health risk was estimated using the concentration data. Cd and As concentrations were significantly higher than in East China. Se and most toxic metal concentrations increased with age (except for the aged people). Furthermore, gender and smoking habits might have a significant impact on toxic metals and Se levels. Multivariable statistics analysis revealed that Se and toxic metals primarily originate in the environment and are then transferred to the human body via the food chain. Dietary habits had an effect on the Se and As concentrations in hair, according to the results of stable isotope analysis. To assess detoxification ability, the Se/ toxic metal molar ratio was used as an indicator. The results demonstrated that the antagonistic effect of Se and Cd, As, Cr, and Hg (molar ratio > 1) could effectively protect residents in the study area from Cd and As pollution in daily life.

Sources, Fraction Distribution and Health Risk Assessment of Selenium (Se) in Dashan Village, a Se-Rich Area in Anhui Province, China.

Soil, rock, potable water, animal food and human hair samples were collected from the Dashan village, a typical selenium (Se)-rich area of China. Se content and fraction distribution were determined to trace the source of soil Se and evaluate the potential health risk to humans. Total Se contents in soils ranged from 0.60 to 10.46 mg kg- 1. The fractions of soil Se followed the order: residual Se (R-Se) > organic-bound Se (O-Se) > acid soluble Se (A-Se) > exchangeable Se (E-Se) > water soluble Se (W-Se). Total Se contents in rocks ranged from 0.07 to 24.8 mg kg- 1. The dietary Se intake of local residents was estimated to be 261.2 µg day- 1 and hair Se content varied from 0.34 to 1.35 mg kg- 1, suggesting that the potential health risk should be concerned. Weathering of carbonaceous rock was speculated to be the primary source of soil Se according to the contents of Se in rocks, the distribution of Se in soil profiles and the relationships between Se and other elements in soils and parent rocks.