Development of an Advanced Life Cycle Impact Assessment Method to Evaluate Radioactivity in Construction Materials

While reducing industrial environmental impacts, it is essential to verify that the perceived improvements do not cause unexpected side effects. In the construction materials sector, certain circular economy practices may potentially increase the exposure from natural radioactivity due to the elevated radionuclide content in processed naturally occurring radioactive material (NORM). This study presents the development of a life cycle impact assessment (LCIA) methodology accounting for NORM impacts in construction material life cycles from cradle to use. The methodology builds upon the LCA-NORM life cycle assessment framework previously established by the research group. The novel contributions include enhancements in (1) the dose units, (2) the use-stage exposure scenario, (3) the inclusion of radionuclide inhalation as an occupational exposure pathway and (4) the revisions of key parameters, including the dose conversion coefficients (DCCs). The updated characterisation factors yielded more conservative values at the use stage (e.g., 7 times higher exposure under pessimistic conditions due to radon inhalation) compared to the previous LCA-NORM outputs. An important advancement is the implementation of the new methodology in a novel custom-developed Python package (i.e., NORMIA) to integrate the custom elementary flows into LCA calculations of the Python library Brightway v.2.5. NORMIA generates characterisation factors that quantify the equivalent stochastic risk for human health and non-human biota per unit radionuclide emission and activity, based on user-defined inputs such as construction material type and density. With this study, a more holistic and accurate assessment of the environmental sustainability of construction materials is targeted.