In 2000, a 9-mile stretch of the Willamette River in Portland, Oregon, was listed as a Superfund site. Sediments, pore water, surface water, and biota in this heavily industrialized segment of the river have been contaminated with PCBs, dioxins, pesticides, PAHs, heavy metals, and other hazardous substances from historical and ongoing sources. Integral is leading the remedial investigation to support the Lower Willamette Group (LWG) and EPA in making cleanup decisions for this complex river system. In support of the remedial investigation, we designed and implemented a phased sampling and modeling approach to characterize the nature and extent of contamination in the affected media; developed detailed upland site summaries of the operations, releases, transport pathways and environmental conditions for more than 75 industrial facilities along the river; and constructed conceptual site models for the harbor-wide study area and 27 initial areas of potential concern (i.e., potential cleanup areas). As part of our overall coordination efforts, Integral has compiled existing data, including chemical and biological data, and a library of more than 6,500 relevant documents, maps, and agency correspondence. We also house and maintain the project’s extensive database, which currently contains approximately 900,000 records, and oversee data quality review/validation according to EPA specifications. Other notable accomplishments include implementing adaptive management strategies for guiding sampling programs; developing an innovative approach for identifying and characterizing groundwater discharge areas; improving the performance of a site-wide hydrodynamic/sediment transport model; and ensuring all specified deliverables were submitted on time and without penalty. As the project progresses, Integral will continue to provide technical leadership and strategic support to the LWG through the completion of the remedial investigation and feasibility study.
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