Research has shown that the potential risk and hazard associated with contaminants in soil are often less than if the contaminant is directly provided to organisms. Contaminants may be tightly bound to soil or sequestered within particles, greatly reducing the potential uptake by people (and other receptors) that are exposed to the soil. Consequently, if soil bioavailability is not considered, the remediation could be larger than necessary to achieve the desired level of protection. Lack of understanding, high cost of in vivo (whole organism) testing and the uncertainty associated with in vitro (test tube) assays are among the most common reasons why relative bioavailability is not considered. In the last decade, the cost of in vitro assays has decreased and their correlation to in vivo studies has improved. This team will bring together the leaders in soil bioavailability testing for inorganic (e.g., arsenic, lead) and organic contaminants (e.g., polycyclic aromatic hydrocarbons) to develop consensus-based regulatory and technical guidance on soil bioavailability. The goal of the project is to help regulators and practitioners select and properly use site-specific bioavailability testing, understand the pros and cons of different in vivo and in vitro methods, and determine which method is most appropriate for site conditions. An Internet-based training course will also be developed.

For more information about the Bioavailability in Contaminated Soil team, please review the Bioavailability in Contaminated Soil Factsheet.