Evaluation of a rat model versus a physiologically based extraction test for assessing phenanthrene bioavailability...

Area of Science:

• Environmental Chemistry
• Toxicology
• Soil Science

Background:

• The soil matrix significantly influences the bioavailability of organic chemicals.
• Soil properties such as organic carbon (OC) content, clay minerals, and pH are key governing factors.
• A physiologically based extraction test (PBET) has been developed to predict chemical bioavailability.

Purpose of the Study:

• To investigate the bioavailability of phenanthrene (PA) from laboratory-treated soils using in vivo and in vitro methods.
• To examine the relationship between an in vivo rat model and an in vitro PBET for assessing PA bioavailability.
• To determine the impact of soil properties (OC, clay, pH) on PA bioavailability.

Main Methods:

• In vivo bioavailability was assessed in Sprague-Dawley rats using oral and intravenous administration of PA-treated soils.
• In vitro bioavailability was evaluated using a physiologically based extraction test (PBET) with artificial digestive fluids.
• Blood concentration-time curves (AUC) and fraction of PA mobilized were quantified.

Main Results:

• Soil matrix significantly reduced PA bioavailability compared to intravenous injection.
• Higher OC and clay content correlated with lower PA bioavailability.
• A significant correlation was found between PBET mobilization and in vivo bioavailability of PA.

Conclusions:

• The PBET assay is a potentially useful alternative for predicting the bioavailability of soil-bound organic chemicals.
• Soil properties demonstrably impact organic chemical bioavailability.
• Further validation with diverse chemicals and soil types is necessary to confirm the PBET's utility.