Comparison of radioactive and stable cesium uptake in aquatic macrophytes affected by the Fukushima Dai-ichi Nuclear Power Plant accident

Concentrations of 134+137 Cs and 133 Cs in aquatic macrophytes, water, and sediment were measured in samples collected from Fukushima Prefecture, Japan. The concentrations of 137 Cs in submerged and floating-leaved plants were higher than the values for emergent plants according to their main Cs uptake mode. The geometric mean water-to-plant concentration ratio for 137 Cs and 133 Cs was comparable observed in submerged and floating-leaved plants, while the geometric mean sediment-to-plant concentration ratio for 137 Cs in emergent plants was higher than that of 133 Cs, which suggest that the mobility of Fukushima accident-derived 137 Cs is not in steady state 4–5 years after the accident.