Fate of selenium in a Se-enriched region of North China: Translocation, bioaccumulation, source, and health benefits

There are limited studies on the translocation and bioaccumulation of selenium (Se) in weak alkaline cultivated Se-enriched soil, and the sources and speciation of Se in wheat grains remain unclear. In this study, we measured the Se levels in soils, roots, stems, and wheat grains from Se-enriched cultivated land in Ci County, China, which has a high incidence of esophageal cancer. The Se levels in the roots were higher than those in the soils, indi-cating that wheat plants bioaccumulated high concentrations of Se from the soil (enrichment coefficient [EC] range from the soil to the root: 0.94-3.29). Redundancy analysis indicated that the bioaccumulated factor, translocation coefficient, and EC were mainly controlled by phosphorus, pH, and Fe2O3 (contribution rates: 37.5%, 19.5%, and 15.9%, respectively). Linear regression analysis revealed that the sources of Se in grains were mainly from the water-soluble fraction (R2 = 0.55, at p < 0.05), the weakly acidic fraction (R2 = 0.84, at p < 0.05), the reducible fraction (R2 = 0.84, atp < 0.05), and the oxidizable fraction (R2 = 0.70, atp < 0.05), as well as from atmospheric deposition (R2 = 0.37, at p < 0.01). There is a significant correlation between the Se from atmospheric deposition and the oxidizable fraction (R2 = 0.62, at p < 0.01) and the residual fraction (R2 = 0.33, at p < 0.01). The contribution of Se input flux from atmospheric deposition was 5.50 g/hm2 for one year. Furthermore, the average content of organic Se in wheat grains was 58.93%. The Se concentrations found in wheat grains were considered beneficial for human health based on a comparison with the Chinese Society of Nutrition standard and worldwide levels. The results of this study will increase the overall knowledge on the theme, which could help prevent and control the harmful effects of undesirable concentrations of Se on human health.

Automated summary

Limited studies have been conducted on the translocation and bioaccumulation of selenium in weak alkaline cultivated Se-enriched soil. This study measured selenium levels in various parts of wheat plants grown in Se-enriched soil in Ci County, China. The results revealed significant bioaccumulation of selenium in the roots, and identified phosphorus, pH, and Fe2O3 as the main factors controlling bioaccumulation. The study also identified the sources of selenium in wheat grains and its potential impact on human health.