PH26 Environmental Decision-Making Case Studies
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(PH309) A Risk Management Case Study: Changes to the ERA Process For CERCLA to Save Time and Money.

McCarthy, C1, Ghose, S2, 1 CH2M HILL, Houston, TX, USA2 US Environmental Protection Agency, Dallas, TX, USA

ABSTRACT- For an ERA conducted at the Rockwool Industries Inc. Superfund Site in Belton, Texas several adjustments were made to EPA's ERA guidance for CERCLA sites. EPA's process was followed through what is commonly referred to as step 3a. After completion of step 3a, an interim record of decision (IROD) was signed that addressed exclusively human health risks. Screening level ecological risk-based PRGs were not developed for the IROD. Steps 3b through 8 were not conducted in areas where remedial actions presented in the IROD sufficiently addressed identified ecological risks by rendering the exposure pathway incomplete. During the Remedial Design/Remedial Action (RD/RA) process, the worst case scenario risks were investigated further in areas where ecological risks were not addressed by proposed remedial options. The further investigation included definitive toxicity tests in sediment without species surveys or habitat evaluations. This approach helped the project save money by minimizing site-specific (baseline ERA [steps 3-8]) sampling. Toxicity tests demonstrated that there was no ecological risk and no further studies were warranted. The adequacy of remedial options presented in the IROD to address only human health risks in sediment were confirmed. The change in approach to ERA helped to effectively evaluate ecological risk without causing any overruns in project schedule that would have resulted from having conducted steps 3b through 8 that includes developing work plans and review cycles. The approach also helped the project save money in several ways; 1) reduced sampling and analysis costs, 2) avoiding costs of conducting and documenting steps 3b through 8, 3) spending money on the ERA in smaller increments, i.e. evaluating only the worst case scenario and working backward, and 4) not cleaning up to ecological risk-based PRGs that extended beyond human health risk-based PRGs. Implementation of this approach should be considered in other future CERCLA projects.

Key words: CERCLA, risk management, ERA

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