Evaluation and verification of foodweb uptake modeling at the Idaho National Engineering Laboratory

The Idaho National Engineering and Engineering Laboratory (INEEL), a United States Department of Energy facility. is located on 2,300 square kilometers of cool desert ecosystem characterized by shrub-steppe vegetative communities. This large complex superfund site has nine "waste area groups and multiple contaminants including radionuclides. The INEEL is systematically evaluating risk to non-human receptors located at the facility. Initial assessments used foodweb modeling to calculate the potential exposure of non-human receptors to contaminants in various media. These foodweb models used literature values, which are primarily based on agricultural studies, for transport of contaminants from soil to non-human receptors. Exposure modeling accuracy is dependent on the quality of input parameter values and the validity of the model's structure (i.e., the degree to which it represents the actual relationships among parameters at the site). Site-specific field measurements of tissue residue levels (concentrations) are the most accurate exposure assessments. In 1997, 1999 and 2000, data was collected both on and off the facility to support the development of site-specific data at the INEEL. These data were compared to the literature values and modeling used in initial risk assessment screening. Results of this study, a comparison and discussion of problems and lessons learned (i.e. non-detects, potential differences in uptake in areas of greater contamination and selection of sites) are presented.