MUD: A Research Model for Radionuclide Migration in the Urban Environment and Drainage Systems

Radionuclides deposited in urban surfaces after atmospheric transport are subject to a number of processes that may affect their permanence and migration through the different components of the urban environment. A significant fraction may reach the drainage systems, the sewage treatment plants and the receiving waters, being the origin of different exposure pathways, not always adequately considered by models in the past. A new model is described, which simulates the above mentioned processes and estimates the amount of radioactivity removed from urban areas, either by natural or by forced decontamination, that from the drainage systems finally goes to the receiving waters, as well as the radioactivity joined with the sludge produced in the sewage treatments plants, whose various applications can represent a potential hazard. The application of the model to post-Chernobyl real-case scenarios is also shown. Finally, the paper is completed with the results of an uncertainty and sensitivity analysis of the model, aimed to identify the key processes and their driving parameters. (author)