The potential for the consideration of bioavailability processes to influence risk-based decision-making is greatest when certain chemical, environmental, and regulatory factors align. Consideration of bioavailability processes is most likely to impact decision-making when the contaminant is, and is likely to remain, the risk driver; when the default assumptions made for a particular site are inappropriate; when significant change to remedial goals is likely (e.g., because large amounts of contaminated soil or sediment are involved); when conditions present at the site are unlikely to change substantially over time; and where regulatory and public acceptance is high. These factors should be evaluated before committing the resources needed for a detailed consideration of bioavailability processes.
Moving bioavailability concepts further into the hazardous waste arena will require specific actions at individual sites, further scientific research on critical bioavailability processes, and large-scale, coordinated testing of bioavailability tools and techniques at pilot sites. At individual sites, assessment of bioavailability processes must be accompanied by uncertainty analysis, process-based long-term monitoring to ensure that present assessments of bioavailability remain accurate and acceptable, and community involvement beginning at the early stages of remediation planning. Although bioavailability is not a unique risk communication problem, experience has demonstrated that communities often have concerns about consideration of bioavailability processes during risk assessments. In order to demonstrate the utility of explicitly considering bioavailability processes and to test new models and tools, adaptive management should be applied to select pilot bioavailability test sites. Adaptive management applies findings from carefully monitored experiments to the adjustment of future management and policy decisions in light of changing conditions and new knowledge.
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