• Among solids in stemflow, particles that permeate 0.45 μm filter are classified as the “dissolved state” (dissolved in water), while those that do not permeate are called the “suspended state” (solid state).
• In stemflow, source of cesium in dissolved state has not yet been clarified.
• In order to clarify the source of cesium in stemflow and its chemical states, composition and chemical states of elements coexisting with cesium in lichens growing on the tree are investigated.

Fig.1　Element analysis of lichens growing on surface of tree trunk (image figure)

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  Fig.2　Concentration of dissolved cesium contained in stem flow (Kawamata Town survey case)

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  Fig.3　Concentration of suspended cesium contained in stem flow (Kawamata Town survey case)

Reference：Sasaki et al., Journal of Environmental Radioactivity, vol.161, pp.58-65 (2016年).

Related articles

• Does radioactive cesium move from the ground surface to underground or into groundwater? 【Vertical movement in soil】
• How does radioactive cesium in forests move from trees to the ground surface? 【Movement in throughfall and stemflow】
• Do high concentrations of radioactive cesium continue to be deposited on riverbeds? 【Deposition of sediment in riverbeds】
• Do high concentrations of radioactive cesium continue to be deposited on riverbeds? 【¹³⁷Cs concentration where sediment continuously deposit】
• Does the concentration in river water change before and after forest fire? How did it change by time?

Reference

1. Niizato, T. et al., Input and Output Budgets of Radiocesium Concerning the Forest Floor in the Mountain Forest of Fukushima released from the TEPCO’s Fukushima Dai-ichi Nuclear Power Plant Accident, Journal of Environmental Radioactivity, vol.161, 2016, p.11-21.