PAH Interactions with Soil and Effects on Bioaccessibility and Bioavailability to Humans

Abstract

This work was conducted in response to SERDP’s 2010 Statement of Need 10-04: Mechanisms of Contaminant Interaction with SoilComponents and its Impact on the Bioavailability of Contaminants. The project evaluated the interactions between polycyclic aromatichydrocarbons and soils, and how these interactions control the oral and dermal bioavailability of PAHs in soil to humans. The studyprovides results that can inform assessments and risk management considerations for DoD sites at which PAH-contaminated soils aredriving clean-up decisions.The objectives included: Task 1) Identify which PAH sources, exposure pathways, and individual PAHs are driving risk assessments andremedial decisions to focus research where it can be most effective; Task 2) Develop an understanding of the mechanisms by which PAHsare sequestered in soil, so the magnitude of bioavailability adjustments can be predicted, and to elucidate factors that control the dissolutionof PAHs from soil; Task 3) Develop an animal model that provides quantitative measures of the relative oral bioavailability of PAHs insoil, and generate a database from this animal model to understand bioavailability across a diversity of soil types and contaminant sources;Task 4) Evaluate use of simple in vitro extraction tests to predict in vivo measures of relative bioavailability; and, Task 5) Assess the effectof soil-chemical interactions on the dermal absorption of PAHs.