Can arsenic bioavailability be predicted in soils using in vitro gastro-intestinal simulation?

Area of Science:

• Environmental Science
• Toxicology
• Geochemistry

Background:

• Arsenic (As) is a toxic soil contaminant posing human health risks.
• Accurate prediction of As bioavailability is crucial for risk assessment.
• Existing in vitro methods show variable suitability for assessing metal(loid) bioavailability.

Purpose of the Study:

• To evaluate the effectiveness of four common in vitro gastrointestinal simulation methods for predicting soil As bioavailability.
• To compare in vitro predictions against an in vivo animal model using industrially contaminated soils.

Main Methods:

• Tested Physiologically Based Extraction Test (PBET), In Vitro Gastrointestinal Method (IVG), Soluble Bioavailability Research Consortium (SBRC), and Unified BARGE Method (UBM).
• Assessed As relative bioavailability (RBA) in 10 industrially contaminated soils.
• Validated in vitro results against an in vivo animal model.

Main Results:

• Soil As RBA varied significantly (15%–68%) across the tested soils.
• Different gastrointestinal simulation methods yielded varying As bioaccessibility results.
• The gastric phase of the Unified BARGE Method (UBMG) demonstrated the strongest correlation with in vivo As RBA (R² = 0.81).

Conclusions:

• UBMG shows superior performance in predicting soil As bioavailability compared to PBET, IVG, and SBRC.
• This study provides evidence for refining human health risk assessments of arsenic in contaminated sites.
• Findings support the use of UBMG for more accurate bioavailability predictions in environmental risk evaluations.