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Exponent to Lead Three-Year Study of Soil/PAH Interactions and Bioavailability


September 16, 2009

As a part of its Strategic Environmental Research and Development Program (SERDP), the U.S. Department of Defense has awarded a $1.5 million contract to an Exponent-led research team. The team will be studying the interactions of various polycyclic aromatic hydrocarbons (PAH) with soil, and the resulting availability of those contaminants to humans (i.e., bioavailability). PAHs have been found to be a key contaminant at many sites, and the question of how bioavailable the chemical is after having been entrained in the soil for a period of time is important in determining the extent of remediation that might be required.

The project will be conducted in five phases, each of which will build on the results of previous phases:

  1. Identify which PAHs tend to drive risk assessments at DoD sites, and determine the key sources and exposure pathways
  2. Assess the degree to which soil/PAH interactions over time influence the chemicals’ bioavailability
  3. Develop an animal model to measure PAH bioavailability via oral exposure, and produce a database of bioavailability across various sources and soil types
  4. Develop an efficient, cost-effective benchtop test for PAH bioavailability from site-specific soils, and validate the test against the animal data
  5. Study the effect of soil/PAH interactions on uptake of the chemical through the skin.

Exponent Senior Managing Toxicologist Yvette Lowney will serve as Principal Investigator on the project. Additionally, Dr. Charles A. Menzie, the Director of Exponent’s EcoSciences practice, will provide an advisory role.

Ultimately, the team hopes to establish a simple method to support bioavailability adjustments for use in human health risk assessment, which would be useful in determining realistic, risk-based soil cleanup standards.