OVERVIEW OF CONCLUSIONS AND RECOMMENDATIONS
The committee found that scientific and technical practices used by EPA for decision making regarding human health risks at the Coeur d’Alene River basin Superfund site are generally sound. The exceptions are minor. However, for EPA’s decision making regarding environmental protection, the committee has substantial concerns, particularly regarding the effectiveness and long-term protection of the selected remedy.
In the human health risk assessment (HHRA), EPA estimated potential lead intake by current and future populations of children using currently available risk assessment procedures with a reasonable degree of certainty. The application of the IEUBK modela was also reasonable but would have benefited from greater collection and use of additional site-specific information. Recognizing the importance of protecting current and future generations, remedial decisions regarding human health appropriately emphasized residential yard remediations. Given the prevalence of high concentrations of lead in soils of the studied communities and the potential for lead exposure of young children, the committee concludes universal blood lead screening of children age 1-4 years is warranted. This screening should be timed to coincide with other routine pediatric health care screening tests. Barring recontamination of remediated properties, it seems probable that the proposed remedies will reduce the targeted human health risks. However, long-term support of institutional-controlb programs should be provided to maintain the integrity of remedies intended to protect human health and guard against health risks from recontamination.
For environmental protection, EPA’s site characterization provided a useful depiction of the metal concentrations in soils, sediments, and surface water over the large spatial scale in the basin. However, the characterization did not adequately address groundwater—the primary source of dissolved metals in surface water—or identify specific locations and materials contributing metals to groundwater. In addition, the committee has serious concerns about the feasibility and potential effectiveness of the proposed remedial actions for environmental protection. There are no appropriate repositories to hold proposed amounts of excavated materials, and establishing them in the basin will probably be extremely difficult. Furthermore, the potential long-term effectiveness of proposed remedial actions is severely limited by frequent flooding events in the basin and their potential to