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

The study investigates the kinetics of 137Cs, 60Co, and 85Sr sorption on powdered building materials in aqueous suspensions at 20°C over interaction times of 1, 7, 14, and 28 days. The distribution coefficient (Kd) values for 137Cs remained largely unchanged throughout the 28 days for all building materials except limestone, while the Kd for 85Sr was significantly lower compared to 60Co, with peak values observed in asphalt and granite. A new layer-by-layer sanding method was developed to analyze radionuclide distribution depth within building materials under varying humidity, time, and temperature conditions. Results indicated that relative humidity had a pronounced effect on 85Sr distribution depth in granite; at 30% relative humidity, 85Sr penetrated 0.5 mm, increasing to 7 mm at 87% relative humidity. These findings highlight the importance of understanding the interactions of radionuclides with urban materials, which can inform more effective decontamination strategies following radiological accidents.