Bioaccessibility of vanadium in respiratory inhalation and skin contact routes by in vitro biomimetic simulations and environmental risk assessment.

Vanadium (V), a toxic element with multiple valence states, is widely distributed in the earth's crust and can be released into the environment through various human activities, posing potential health risks to humans. Understanding the bioaccessibility of V is crucial for assessing its potential toxicity and health risks. This study investigated the bioaccessibility of V via respiratory inhalation and dermal contact using in vitro biomimetic simulations. Results showed significant variations in V bioaccessibility among different sample types, V valence states, and exposure pathways. For respiratory exposure, in lung epithelial cell gap fluid, the bioaccessibility of V(IV) and V(V) in vanadium-titanium concentrate was 21.10% and 49.67%, respectively, and in lung macrophage lysosomal fluid simulations was 25.00% and 32.69%.The vanadium-titanium concentrate exhibited higher bioaccessibility of V than the soils and the dusts in both lung epithelial cell gap fluid and lung macrophage lysosomal fluid simulations. In dermal exposure simulations, V bioaccessibility was relatively low and varied with the composition of the simulated sweat solutions. The bioaccessibility of both V(IV) and V(V) in simulated sweat BS-1 solution (pH = 6.5) was the highest (3.70-4.91%), followed by in BS-2 (pH = 4.7) at 2.93-4.30%, while in BS-3 (pH = 5.5) was the lowest (2.16-4.99%). This study demonstrates significant variations in V bioaccessibility across different exposure pathway and matrix. These findings provide insights for health risk assessments of V contamination.