In order to illustrate the value and challenges of risk-of-remedy analyses, acase study is presented in which risk-of-remedy and post-remedy risk analyses areemployed to support the remedy selection for a New Jersey site that is contaminated withpolychlorinated biphenyls (PCBs) in both terrestrial and aquatic habitats. Based on theassessment of current and reasonably likely future site conditions, applicable technologies,and regulatory requirements and precedence, the preferred remedy consists oftargeted removal/off-site disposal of soil and sediment containing high concentrations ofPCBs, with on-site consolidation of soils and sediments containing lower concentrationsof PCBs. In addition, consideration has been given to restoring a portion of the Site forlimited recreational use.To ensure that the proposed remedial action would address the human-healthconcerns identified in the baseline risk assessment, a post-remedy human-health riskassessment was performed considering the baseline exposure scenarios (workers andtrespassers), as well as a post-remedy recreational visitor scenario. Exposure pointconcentrations for chemicals of potential concern in each exposure unit were recalculatedto reflect the targeted off-site removal/on-site consolidation of PCB-containing soils. Theanalysis showed that predicted risks to all human receptors would be within acceptabletarget risk levels for the Site, thus indicating that the proposed remedy would beprotective of human health. Similarly, to ensure that the proposed remedial action wouldaddress the ecological concerns identified in the baseline risk assessment, and wouldresult in the least adverse impact on the ecosystem, a qualitative assessment of netenvironmental benefits was also performed, considering: (1) residual ecological risksposed by Site contaminants before and after implementation of the selected remedy; (2)changes in the functional values of each habitat expected to result from implementing theproposed remediation; (3) rate of recovery for the biological community followingremediation and certainty of that outcome; (4) designated uses impaired during recovery;and (5) the likelihood that the remedy will achieve remedial action objectives. Theseimplementation and post-remedy risk analyses demonstrated that the selected remedialalternative would result in the greatest net human-health and environmental benefitamong the alternatives considered for the site, including mitigating unanticipated risks toworkers and nearby residents during remedy implementation and avoiding costly delaysfor substantial remedy modifications, habitat restoration, or even abandonment of anincomplete remedy.
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