Effect of vitamin C supplement on lead bioaccessibility in contaminated soils using multiple in vitro gastrointestinal assays: Mechanisms and health risks

Effects of vitamin C supplementation on the oral bioaccessibility of lead (Pb) present in contaminated soils were examined using a number of in vitro assays (PBET, SBRC, UBM and IVG). In the presence of vitamin C, an increase in Pb bioaccessibility was observed in the gastric phase by 1.3-fold (30.5%-85.5%) and in the intestinal phase by 3.1-fold (0.9%-58.9%). Lead mobilization was regulated by reductive dissolution of Fe(III) and sequestration of Pb on secondary Fe minerals. Sequential extraction by the Bureau Community of Reference (BCR) provided more evidence that reducible fraction and residual fraction were major contributor of gastric Pb bioaccessibility, as well as reduced fractions in intestinal Pb bioaccessibility. In addition, higher non-carcinogenic risks may occur based on target hazard quotient (THQ >= 1). For people exposed to Pb present in soil, the management of vitamin C supplements is of serious concern.

Automated summary

The study revealed that the supplementation of vitamin C increased the oral bioaccessibility of lead in contaminated soils, mainly by enhancing the release of lead in the gastric phase and its reduction in the intestinal phase. However, there is a higher non-carcinogenic risk associated with this, highlighting the need for careful management of vitamin C supplements for individuals exposed to lead in soil.