T3 AM Ecological Risk Assessment (Part 2)
Tuesday, 15 November 2005: 8:00 AM - 11:40 AM in Ballroom 3

(MAR-1117-898109) Ecological Risk Assessment Methods for Evaluating Legacy Contaminants at the Hanford Site.

Markwiese, J¹, Ryti, R¹, ¹ Neptune and Company, Los Alamos, New Mexico, USA

ABSTRACT- The Hanford Site, occupying an area of over 1,500 km2 (586 mi2) near Richland Washington, became a Federal facility in 1943 when the U.S. Government took possession of the land to produce nuclear materials for defense purposes; its mission is now to clean up the radioactive and hazardous wastes that had been generated during the previous years. The risks posed by multiple chemicals (primarily metals) and radionuclides associated with past operations will need to be integrated in a comprehensive assessment to determine the potential for adverse effects on terrestrial biota. Areas targeted for data collection include the interior of the Hanford Site (approximately 195 km2; 75 mi2) and former nuclear reactors and weapons facilities along approximately 32 km (20 mi) of the Columbia River shoreline; individual waste sites within these areas range from 1 m2 to several hectares. Data will be collected from over 40 1-hectare plots representing both remediated and unremediated areas and reference sites across a continuum of actively managed sites to native shrub-steppe habitat. The hectare sized plots represent the boundaries for an assessment population of middle trophic level receptors (small mammals) that are the focus of this investigation. Data-collection activities will involve surface (15 cm, 6 in) soil sampling for contaminants using a multi-increment collection procedure, contaminant analysis of biota (including plants, invertebrates, reptiles and small mammals), measures of decomposition, toxicity testing (invertebrate and plant), and field surveys of community composition, diversity and related measures. This effort will result in soil and biota information to support remedial decision-making and provide information to evaluate the condition of the ecosystem across the terrestrial environment of the Hanford Site.

Key words: Hanford, Terrestrial, Radionuclides, Metals