Abstract
Sites previously used for disposal of radioactive and hazardous chemical materials have resulted in situations that pose a potential threat to humans from inadvertent intrusion. An example of a generic scenario analysis was developed to demonstrate the evaluation of potential exposure to cleanup workers or members of the public who intrude into buried waste containing both radioactive and hazardous chemical contaminants. The example scenarios consist of a collection of exposure routes (or pathways) with specific modeling assumptions for well drilling and for excavation for building construction. These scenarios are used to conceptually describe potential patterns of human activity during intrusion into mixed-waste disposal sites, assuming that no protective measures are taken. Radiation doses are calculated using the GENII software system and converted to risk using factors from the International Commission on Radiological Protection in Publication 60. The hazard assessment for nonradioactive materials is performed using recent guidance from the U.S. Environmental Protection Agency. The example results are in the form of cancer risk for carcinogens and radiation exposure. They indicate that radiation doses potentially received during excavation would exceed those received during well drilling, primarily because of the increased exposure duration. Applying the results of these scenarios to an occupational setting may provide an upper bound of the risk resulting from one exposure event.