Beryllium in contaminated soils: Implication of beryllium bioaccessibility by different exposure pathways

Area of Science:

• Environmental Science
• Toxicology
• Geochemistry

Background:

• Inhalation exposure to beryllium (Be) and its toxicity are established.
• Limited research exists on Be bioaccessibility from soils via various exposure pathways.
• Understanding bioaccessibility is crucial for assessing health risks at contaminated sites.

Purpose of the Study:

• To examine beryllium (Be) bioaccessibility in soils from a legacy radioactive waste disposal site.
• To compare bioaccessibility across multiple in vitro ingestion, inhalation, and dynamic methods.
• To evaluate the influence of different exposure routes on Be bioavailability and potential toxicity.

Main Methods:

• Utilized in vitro ingestion methods: Solubility Bioaccessibility Research Consortium (SBRC), physiologically based extraction test (PBET), and in vitro gastrointestinal (IVG).
• Employed simulated epithelial lung fluid (SELF) for inhalation exposure assessment.
• Applied dynamic two-stage bioaccessibility (TBAc) and nitric acid (HNO3) extraction for comprehensive analysis.

Main Results:

• High Be extraction percentages observed in the gastric and intestinal phases across SBRC, PBET, and IVG methods (56-70%).
• Similar Be bioaccessibility (~18%) in PBET-intestinal phase and SELF, attributed to chelating agents.
• Dynamic TBAc-intestinal phase showed significantly higher Be extraction (20.8%) compared to single-phase SBRC-intestinal phase (4.8%).

Conclusions:

• Beryllium bioaccessibility is influenced by factors including solution pH, extraction time, soil composition, particle size, and chelating agents.
• Inhalation exposure followed by gastrointestinal transfer may increase Be bioaccessibility and toxicity.
• Findings are significant for understanding Be exposure routes and informing risk-based management of contaminated sites.