October 28, 2024 5th IER seminar of FY2024 was held. ＜Graduate Student, Associate Professor WAKIYAMA, Professor TSUKADA＞
| Date & Time | Mon. October 28, 2024, 13:30-15:20 JST | |||||
| Venue | 6F Conference room, Main Bldg. IER/Online (Zoom) | |||||
| Speakers | KUROSAWA Honoka (Third year doctoral student, major in Environmental Radioactivity) Associate Professor WAKIYAMA Yoshifumi Professor TSUKADA Hirofumi | |||||
| Lecture Titles | Study on 137Cs dynamics in the pond contaminated by Fukushima Dai-ichi Nuclear Power Plant accident (Kurosawa) Comparison of 137Cs dynamics during high-flow events between Abukuma and Ukedo rivers (Wakiyama) Temperature dependence of 137Cs release from sediment collected at Ogaki Dam reservoir (Tsukada) Participants: 21 | |||||
Institute of Environmental Radioactivity (IER) regularly holds the IER seminar in which the faculty members report on their research results, with the aim of facilitating their research activities and promoting communication.
In the 5th IER seminar of this fiscal year that was held on October 28, 2024, three presentations were given by one doctoral student majoring in Environmental Radioactivity, Associate Professor, WAKIYAMA Yoshifumi and Professor, TSUKADA Hirofumi to 21 participating researchers and students as follows.
Ms. Kurosawa in Wakiyama Laboratory presented on the 137Cs dynamics in the decontaminated urban pond. Bottom sediment, pond water, inflow water, and outflow water from the pond, which was decontaminated by bottom sediment removal in 2017, were collected in 2015 and from 2018 to 2022, and measured for 137Cs concentration and other parameters. The presentation covered the impact of decontamination on 137Cs dynamics, the long-term 137Cs accumulation process after decontamination, and the impact of the urban environment on the pond.
Dr. Wakiyama (Associate Professor) talked about “Comparison of 137Cs dynamics during high-flow events between Abukuma and Ukedo rivers”. Based on the analysis of water samples collected after heavy rainfalls from the river and coastal areas near the river mouth in two river water systems, he explained the variations in 137Cs concentration in the river water, the estimated amount of its exportation, and its impact on the coastal seawater.
Professor Tsukada presented on the “Temperature dependence of 137Cs release from sediments collected at Ogaki Dam reservoir”. The sediment was sealed and left at 5, 10, 20, and 30℃ for 5 to 100 days to study the 137Cs leaching from the sediments. The results showed that the leaching rate was higher at higher temperatures and longer periods of leaving time. The main factor was the increase in ammonium concentration, although other factors were also involved, and the leaching followed the Arrhenius equation.
After each presentation, various questions and comments were raised by IER faculty members and graduate students.
