A modelling framework to analyze climate change effects on radionuclide aquifer contamination

Abstract

Non-stationarity of climatic variables (e.g., temperature and precipitation) due to Climate Change (CC) can affect the migration processes of radionuclides released from nuclear activities. In this paper, a framework of analysis is developed to predict the evolution in time of contaminant concentration and fluence under different Climatic Boundary Conditions (CBCs) of precipitation scenarios provided by a climate model integrated with an accurate physical coupled hydraulic-transport model. A case study is worked out with respect to the migration of a radioactive contaminant (²³²Th) at Kirtland Air Force Base (Albuquerque, New Mexico, USA), for which the different CBCs considered are: i) stationary and ii) non-stationary precipitation. The effects of such alternative hypotheses on the physical modelling results are analysed, using a cross-wavelet analysis. It is shown that fluence is strongly affected by precipitation extremes, more than concentration, and it is claimed that a daily scale on the information and data of CBCs is necessary to model, with sufficient accuracy, the migration process and properly assess the impact of future CC on groundwater contamination.

Keywords: Aquifer contamination; Climate change; Cross-wavelet analysis; Precipitation extremes; Radionuclide migration.