Accumulation of 137Cs in puddle sediments within urban ecosystem

The role of puddle sediments as a final depot of 137Cs horizontal migration within the urban landscape is studied using the example of Ekaterinburg city, Russia. Radioactive contamination in the city appeared due to fallout after atmospheric testing of nuclear weapons and nuclear accidents. Contamination density of 137Cs in the region was assessed from archive data to be about 5.1 kBq/m2, of which the maximum activity concentration (<30 Bq/kg) is associated with the upper 15 cm soil layer. Results of the survey reported here indicate a mean 137Cs activity concentration in puddle sediments of 80 Bq/kg, with a maximum value of 540 Bq/kg. It is estimated that horizontal migration has led to about a fourfold concentration of 137Cs in puddle sediments.