Natural radionuclides (NORM) in a Moroccan river affected by former conventional metal mining activities

Abstract The main aim of this work was to determine the levels of multiple natural radionuclides in an aquatic system (Moulouya River, Morocco) impacted by multiple abandoned Zinc and Lead mines. 238 U, 234 U, 232 Th, 230 Th and 210 Po were determined by alpha-particle spectrometry in water and sediment samples collected along the river and in samples from three pit lakes of abandoned mines, located in the Upper Moulouya catchment area. The results enabled the analysis of the different levels of impact of former mining activities, depending on the natural radionuclides. While the activity concentration of U-isotopes in Moulouya River water was slightly elevated in the vicinity of abandoned mine wastes, other natural radionuclides (Th-isotopes and 210 Po) levels were typical of a natural environment. This fact is clearly reflected in the magnitude and range observed in the distribution coefficients for the different radionuclides analyzed.