Long-term Cs dynamics after decontamination of an urban pond in Fukushima Prefecture, Japan.

Cs tends to accumulate in ponds and dam reservoirs because of inputs from their catchments. Ponds contaminated by the Fukushima Daiichi Nuclear Power Plant accident have since been decontaminated. However, little attention has been paid to Cs accumulation after the decontamination measures, such as bottom sediment removal, especially for urban ponds with reportedly high Cs concentrations in their urban catchments.

Applicability of reconstruction of temporal changes in 137Cs concentrations in pond water based on the vertical distribution of bottom sediments: a case in three ponds in the Fukushima evacuation zone.

Long-term changes in particulate and dissolved 137Cs concentrations in rivers and dam reservoirs have been reconstructed using 137Cs depth distributions in bottom sediments near Chornobyl and Fukushima. However, few studies have applied this method to pond water. This study tested the applicability of this reconstruction method in ponds within the Fukushima evacuation zone.

Distinct food-web transfers of Cs to fish in river and lake ecosystems: A case study focusing on masu salmon in the Fukushima evacuation zone.

This study was conducted to elucidate the spatial and size variations, and food-web transfer of Cs in freshwater fish in the upper reaches of the Ukedo River system, a highly contaminated river system flowing through the Fukushima evacuation zone. Fish collection and environmental surveys were conducted in the summer of 2020 at five forest rivers and at the Ogaki Dam reservoir (an artificial lake) with different air dose rates (mean 0.20-3.