ASSESSING THE CONSEQUENCES OF EXPOSURE TO NATURALLY OCCURRING ASBESTOS (NOA): COMPARING CURRENT RISK PROTOCOLS, EXPOSURE METRICS, AND METHODS FOR QUANTIFYING EXPOSURE

The primary concern with exposure to NOA is the attendant health risk. Multiple protocols exist for assessing/predicting such risks including the current approach used by EPA and the one proposed in Berman and Crump (2008) along with its earlier version (Berman and Crump 2001). Sufficient data have now been collected from several sites to support a comparison of predicted risks based on the various protocols. The implications from such a comparison will be discussed.

All of the risk protocols require exposure concentration estimates as input and multiple approaches for assessing such exposure are currently in use. Therefore, the relative merits of estimating exposure concentrations by “activity-specific sampling”, by soil sampling (using each of varying methods) with attendant modeling, and by a combination of two will also be compared and the implications discussed.

Given that rocks and soils potentially containing asbestos cover as much as a third of the United States, the best scientific methods need to be employed to inform the risk management decisions that will be required for these areas.