Coeur d’Alene River Basin – Human Health Risk Assessment Activities

WSB, through its legacy firm Alta Science & Engineering, Inc., completed a comprehensive Human Health Risk Assessment (HHRA) to evaluate potential exposures and associated risks within the Coeur d’Alene River Basin.

The assessment integrated data from state and federal health and exposure surveys, the Remedial Investigation/Feasibility Study (RI/FS) process, and the ongoing Natural Resource Damage Assessment. Drawing on these sources, our team defined the extent of heavy metal contamination, evaluated potential human health risks and provided the technical foundation needed to support informed remediation decisions and cleanup criteria.

This work included site-specific quantitative analysis of the relationship between observed blood lead levels and environmental conditions, along with one of the most extensive evaluations of lead-based paint as an additional exposure source at a CERCLA site. We also analyzed blood lead data in relation to yard and household dust lead levels to help evaluate program effectiveness.

In collaboration with the Coeur d’Alene Tribe, we assessed subsistence scenarios reflecting both traditional and current lifestyles within the river floodplain, considering exposures for children and adults engaged in these practices.

To support a consistent and defensible assessment, we developed procedures to address data gaps and integrate multiple datasets into a comprehensive, compatible framework. WSB led the lead-risk portion of the HHRA, working alongside an EPA contractor responsible for non-lead risks, and combined these efforts into a draft HHRA document released in June 2000.

The final report was recognized by multiple stakeholders, including the EPA’s Technical Review Work Group for Lead, as an innovative and comprehensive assessment.