Using Adaptive Management to Streamline the Remedial Investigation/Feasibility Process for the Anniston PCB Site

摘要

Background/Objectives. The Anniston Site (the Site) is located in the north-central part of Alabama, near the city of Anniston. The Site has been investigated for the past 20 years based on the presence of polychlorinated biphenyls (PCBs) and other chemical constituents that might occur in various Site media. Geographically extensive, the Site encompasses the Solutia Inc. (formerly Monsanto) Anniston Plant (the Plant) and grounds, residential and nonresidential properties, and stretches of both Choccolocco Creek and Snow Creek and their associated floodplains. Given its large and complex nature, the Site has been segmented into three operable units (OUs). OU-1/OU-2 is an approximate 1,000-acre area of floodplain with residential and nonresidential properties and five miles of Snow Creek. OU-3 encompasses the Plant and the grounds immediately surrounding it. OU-4 is the largest OU and includes approximately 35 miles of Choccolocco Creek from (and including) the confluence with Snow Creek downstream to its confluence with the Coosa River. Approach/Activities. While not a National Priority List (NPL) Superfund site, the Site’s remedial investigation/feasibility study (RI/FS) is being conducted under a partial consent decree issued under the provisions of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). All work conducted at the Site must also comply with the National Contingency Plan. With a record of decision having already been issued for OU-3 and the residential removal program in all OUs essentially complete, a key focus for Site activities is completing the RI/FS for OU-1/OU-2 and OU-4. The adaptive site management (ASM) process has been integrated to various aspects of the RI/FS processes for both of these OUs, including approval from the United States Environmental Protection Agency (USEPA) to use ASM for evaluating the constituents of potential concern (COPCs). A project-specific process decision flow chart was developed and used in scoping the initial field investigations, shaping the next phases of data collection, and ultimately scoping the ensuing RI/FS-related documents. Results/Lessons Learned. The underlying premise for this presentation is that the easy decision is to analyze all collected samples for all possible constituents. However, by sampling for all possible constituents, the difficult decisions regarding which constituents are important to a site are simply pushed further into the RI/FS process. Each time the decision regarding COPCs is pushed further into in the RI/FS process, significant resources- both schedule and financial-are expended evaluating information that is ultimately not material to the overall risk management decision for the site. This presen