Bioassay-Based and Parameter-Optimized Bioaccessibility Assay to Predict Chromium Oral Bioavailability from...

Area of Science:

• Environmental Science
• Toxicology
• Biochemistry

Background:

• Oral exposure to toxic chromium in contaminated soil poses significant human health risks.
• Assessing chromium bioavailability is crucial for risk evaluation and remediation strategies.

Purpose of the Study:

• To develop and validate an in vitro bioaccessibility assay for predicting chromium relative bioavailability (Cr-RBA) in soils.
• To optimize assay parameters for improved prediction accuracy of in vivo Cr-RBA.

Main Methods:

• A mouse urine bioassay was used to determine Cr-RBA in soils.
• Three in vitro bioaccessibility assays (SBRC, PBET, IVG) were evaluated against in vivo data.
• Response surface methodology with Box-Behnken Design was employed to optimize the SBRC-GP assay parameters.

Main Results:

• Initial in vitro assays showed variable Cr bioaccessibility and moderate correlations with in vivo Cr-RBA.
• The optimized SBRC-GP assay (pH 1.2, 1:150 S/L ratio, 2h) significantly increased Cr bioaccessibility (2.3-4.2 fold).
• The modified assay demonstrated improved prediction of soil Cr-RBA (R² = 0.66, slope = 1.0).

Conclusions:

• An optimized SBRC-GP in vitro bioaccessibility assay effectively predicts chromium bioavailability in soils.
• This optimized assay aids in assessing health risks from soil ingestion and refining remediation goals for chromium-contaminated sites.