Fate and transport of radiocesium, radiostrontium and radiocobalt on urban building materials

This study investigates the fate and transport of water-soluble radionuclides, specifically radiocesium (137Cs), radiostrontium (85Sr), and radiocobalt (60Co), in urban building materials. Kinetics of radionuclide sorption on powdered building materials in aqueous suspensions were examined at 20°C over interaction times of 1, 7, 14, and 28 days. Results show that the distribution coefficient (Kd) for 137Cs remained relatively unchanged in most materials, except for limestone. Notably, the Kd for 85Sr was several orders of magnitude lower than that for 60Co, with the highest sorption observed in asphalt and granite. The study also developed an innovative layer-by-layer sanding method to measure radionuclide distribution depth within selected building materials under varying humidity, time, and temperature conditions. It was found that relative humidity significantly impacted 85Sr penetration in granite, which varied from 0.5 mm at 30% RH to 7 mm at 87% RH. Understanding these interactions is vital for improving decontamination methods and addressing radiological contaminants in urban environments.