CALCULATING ECONOMIC RISK AFTER HANFORD CLEANUP

Since late 1997, researchers at the Hanford Site have been engaged in the Groundwater Protection Project (formerly, the Groundwater/Vadose Zone Project), developing a suite of integrated physical and environmental models and supporting data to trace the complex path of Hanford legacy contaminants through the environment for the next thousand years, and to estimate corresponding environmental, human health, economic, and cultural risks. The linked set of models and data is called the System Assessment Capability (SAC). The risk mechanism for economics consists of ''impact triggers'' (sequences of physical and human behavior changes in response to, or resulting from, human health or ecological risks), and processes by which particular trigger mechanisms induce impacts. Economic impacts stimulated by the trigger mechanisms may take a variety of forms, including changes in either costs or revenues for economic sectors associated with the affected resource or activity. An existing local economic impact model was adapted to calculate the resulting impacts on output, employment, and labor income in the local economy (the Tri-Cities Economic Risk Model or TCERM). The SAC researchers ran a test suite of 25 realization scenarios for future contamination of the Columbia River after site closure for a small subset of the radionuclides and hazardous chemicals known to be present in the environment at the Hanford Site. These scenarios of potential future river contamination were analyzed in TCERM. Although the TCERM model is sensitive to river contamination under a reasonable set of assumptions concerning reactions of the authorities and the public, the scenarios show low enough future contamination that the impacts on the local economy are small