Bioaccessibility of Antimony in Solid Environmental Matrices

Antimony (Sb) is a critical raw material whose extraction, processing, and use contribute to environmental contamination and to its enrichment in soils, dusts, slags, and mining residues. Human exposure to Sb occurs through, among others, incidental ingestion of contaminated particles, making oral bioaccessibility an important parameter for human health risk assessment. This study investigated the in vitro oral bioaccessibility of Sb in solid environmental matrices and evaluated the influence of geochemical properties, environmental matrix type, and analytical methodology. A meta-analysis was conducted using data from 20 peer-reviewed studies published between 2009 and 2025, comprising 175 samples of soils, dusts, and mining waste analyzed using established in vitro bioaccessibility methods. Total Sb concentration was identified as the strongest predictor of both gastric and intestinal Sb bioaccessibility. Differences in gastric and intestinal bioaccessibility were observed between soils, dust and mining waste samples, while no conclusions could be drawn for intestinal bioaccessibility. The results demonstrate that Sb bioaccessibility is governed primarily by total Sb concentration, while methodological and mineralogical factors contribute to additional variability. Relative gastric bioaccessibility was also influenced by the in vitro method used, with Method 1340 and the UBM generally yielding lower values than the PBET, SBET, and SBRC. However, without a paired design, any causal conclusion about the optimality of a particular test is premature.