Comparison of batch mode and dynamic physiologically based bioaccessibility tests for PAHs in soil samples.

Area of Science:

• Environmental Chemistry
• Toxicology
• Analytical Chemistry

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants of concern.
• Accurate assessment of human exposure to PAHs in soil is crucial for risk evaluation.
• Existing methods may not fully represent human ingestion conditions.

Purpose of the Study:

• To develop and validate an in vitro methodology for measuring human ingestion bioaccessibility of PAHs in soil.
• To establish a standardized test for commercial laboratories.
• To support site-specific quantitative risk assessments.

Main Methods:

• Development of the Fed ORganic Estimation human Simulation Test (FOREhST) protocol.
• Utilized methanolic KOH saponification, solid-phase extraction (SPE) with polymeric and silica sorbents for cleanup and preconcentration.
• Analyzed PAHs using high-pressure liquid chromatography with fluorescence detection.

Main Results:

• The FOREhST method demonstrated good repeatability (approx. 10% RSD) for six key PAHs in eleven soils.
• Results correlated well with an independent dynamic human simulation reactor.
• Bioaccessible PAH fractions ranged from 10-60%, influenced by PAH compound, soil type, and organic carbon content.

Conclusions:

• The developed FOREhST method is a robust and reproducible tool for assessing PAH bioaccessibility in soil.
• This methodology can be utilized in commercial testing laboratories for risk assessment.
• Findings support more accurate, site-specific risk estimations for PAH-contaminated soils.