1. Photo: T. Ishimaru Nov. 13, 2012 Sanjo Conference Hall, University of Tokyo Long-term Sources: To what extent are marine sediments, coastal groundwater, and rivers a source of ongoing contamination? Jota Kanda Tokyo University of Marine Science and Technology

2. 137 Cs release to the sea (PBq) Data sources: Chino et al. (2011), Tsumune et al. (2011), Bailly du Bois et al. (2011). Morino et al. (2011), Stohl et al. (2011), Gray et al. (1995), Aarkrog (2003), UNSCEAR (2000) 137 Cs release to the sea (PBq) Data sources: Chino et al. (2011), Tsumune et al. (2011), Bailly du Bois et al. (2011). Morino et al. (2011), Stohl et al. (2011), Gray et al. (1995), Aarkrog (2003), UNSCEAR (2000) Significant release in a brief period to the open sea Impact of Fukushima

3. 137 Cs in seawater and sediment Seawater: immediate vicinity of the plant Sediment: off Fukushima <200m depth Data sources: TEPCO, Fukushima Pref. Govt., MEXT 137 Cs in seawater and sediment Seawater: immediate vicinity of the plant Sediment: off Fukushima <200m depth Data sources: TEPCO, Fukushima Pref. Govt., MEXT Rapid flushing of contaminated water vs. Persistent sediment radioactivity 137 Cs radioactivity (Bq/L) 137 Cs radioactivity (Bq/kg-dry) Sediment Seawater

4. 134 Cs+ 137 Cs radioactivity in two fish species from Fukushima Data source: Fisheries Agency of Japan 134 Cs+ 137 Cs radioactivity in two fish species from Fukushima Data source: Fisheries Agency of Japan vs. Mysterious resilience of fish radioactivity Rapid flushing of contaminated water

5. Remaining 137 Cs in <200m coastal waters (April-September 2012) Fukushima Dai-ichi Nuclear Power Plant N. Yoshida and J. Kanda (2012) Science, 336: 1115-1116.

6. Remaining 137 Cs in <200m coastal waters (April-September 2012) Data sources and methods Seawater inventory 137 Cs (Bq/L) data: TEPCO, MEXT n=636 2 stations adjacent to the plant are not included -multiplied by water-column volume Sediment inventory 137 Cs (Bq/kg-dry, top sediment) data: TEPCO, Fukushima Pref. Govt., MEXT n=299 -converted to area-based activity (Bq/m 2 ) with 137 Cs data of known core volume (JOS/NHK, TUMSAT, n=59) - m ultiplied by area Data sources and methods Seawater inventory 137 Cs (Bq/L) data: TEPCO, MEXT n=636 2 stations adjacent to the plant are not included -multiplied by water-column volume Sediment inventory 137 Cs (Bq/kg-dry, top sediment) data: TEPCO, Fukushima Pref. Govt., MEXT n=299 -converted to area-based activity (Bq/m 2 ) with 137 Cs data of known core volume (JOS/NHK, TUMSAT, n=59) - m ultiplied by area Fukushima Dai-ichi Nuclear Power Plant

7. Top sediment 137 Cs (Bq/kg-dry) Areal 137 Cs (Bq/m 2 ) TUMSAT time-series monitoring (July 2011, Oct. 2011, May 2012) T. Ishimaru, T. Aono, Y. W. Watanabe, M. Aoyama, Y. Hamajima, A. Tsuda, M. Uematsu, S. Igarashi, Y. Yamaguchi, Y. Ito, Y. Tanaka, K. Tsuchiya, H. Kohno, M. Moteki, K. Uchida, K. Amakasu, N. Iwasaka, H. Arakawa, H. Ohashi, M. Ishida, M. Kawabe, Y. Kasajima, T. Hosaka, and dedicated students TUMSAT time-series monitoring (July 2011, Oct. 2011, May 2012) T. Ishimaru, T. Aono, Y. W. Watanabe, M. Aoyama, Y. Hamajima, A. Tsuda, M. Uematsu, S. Igarashi, Y. Yamaguchi, Y. Ito, Y. Tanaka, K. Tsuchiya, H. Kohno, M. Moteki, K. Uchida, K. Amakasu, N. Iwasaka, H. Arakawa, H. Ohashi, M. Ishida, M. Kawabe, Y. Kasajima, T. Hosaka, and dedicated students JOS/NHK 20km-zone survey (Nov./Dec. 2011) K. Hanawa, A. Tsuda, Y. Kato, T. Ishimaru, T. Aono, K. Ikehara, M. Yamamoto, M. Fujiwara, H. Yamazaki, T. Koike, and personnel from NHK, Sanyo Techno Marine Inc., and ING Co. Ltd. JOS/NHK 20km-zone survey (Nov./Dec. 2011) K. Hanawa, A. Tsuda, Y. Kato, T. Ishimaru, T. Aono, K. Ikehara, M. Yamamoto, M. Fujiwara, H. Yamazaki, T. Koike, and personnel from NHK, Sanyo Techno Marine Inc., and ING Co. Ltd.

8. Remaining 137 Cs in <200m coastal waters (April-September 2012) Fukushima Dai-ichi Nuclear Power Plant Total inventory Seawater: 15.3 TBq Sediment:93.5 TBq Total inventory Seawater: 15.3 TBq Sediment:93.5 TBq 1.8 16.1 1.8 16.1 1.4 11.6 1.4 11.6 3.0 23.9 3.0 23.9 3.7 23.3 3.7 23.3 3.2 11.2 3.2 11.2 2.3 11.2 2.3 11.2 Direct discharge ( ～ April 2011) 3600 ～ 27000 TBq Direct discharge ( ～ April 2011) 3600 ～ 27000 TBq Only <3% of the discharged 137 Cs Only <3% of the discharged 137 Cs Seawater (TBq) Sediment (TBq) Seawater (TBq) Sediment (TBq) TBq: 10 12 Bq

9. Abukuma Naka Kuji Naruse/Nanakita/Natori Small rivers 137 Cs discharge estimate River water ･ Annual precipitation ・ Basin area ・ Runoff coefficient: 0.7 ・ River water 137 Cs: <<1Bq/L (MOE) Suspended/Bed load ・ Specific sediment yield 300m 3 /km 2 /year (Okano et al. 2004) ・ Basin area ・ Riverbed/bank sediment 137 Cs (MOE) 137 Cs discharge estimate River water ･ Annual precipitation ・ Basin area ・ Runoff coefficient: 0.7 ・ River water 137 Cs: <<1Bq/L (MOE) Suspended/Bed load ・ Specific sediment yield 300m 3 /km 2 /year (Okano et al. 2004) ・ Basin area ・ Riverbed/bank sediment 137 Cs (MOE) Rivers/Drainage basins

10. Naka Kuji Validation Suspended/Bed load estimated for Abukuma in summer 2011 0.72 TBq/month cf. Yamashiki et al. (2012) Estimation of Radioactive Contaminant Load from Abukuma River Japan Geophysical Union Meeting 2012 Combined water and suspended load at Abukuma river mouth in summer 2011 (baseflow only) 0.87 TBq/month Validation Suspended/Bed load estimated for Abukuma in summer 2011 0.72 TBq/month cf. Yamashiki et al. (2012) Estimation of Radioactive Contaminant Load from Abukuma River Japan Geophysical Union Meeting 2012 Combined water and suspended load at Abukuma river mouth in summer 2011 (baseflow only) 0.87 TBq/month 137 Cs discharge from rivers Abukuma Naruse/Nanakita/Natori Small rivers

11. Abukuma Naka Kuji Naruse/Nanakita/Natori <<0.20 0.033 <<0.20 0.033 <<0.32 0.41 <<0.32 0.41 <<0.41 0.28 <<0.41 0.28 <<0.11 0.011 <<0.11 0.011 <<0.25 0.046 <<0.25 0.046 Water (TBq/month) Sediment (TBq/month) Water (TBq/month) Sediment (TBq/month) 1.Ukedo 1.Ukedo <<0.034 0.19 2.Niida 2.Niida <<0.024 0.050 3.Kuma 3.Kuma <<0.005 0.035 4.Tomioka 4.Tomioka<<0.005 0.019 1.Ukedo 1.Ukedo <<0.034 0.19 2.Niida 2.Niida <<0.024 0.050 3.Kuma 3.Kuma <<0.005 0.035 4.Tomioka 4.Tomioka<<0.005 0.019 5.Ohta 5.Ohta <<0.008 0.017 6.Mano 6.Mano <<0.018 0.015 7.Natsui 7.Natsui <<0.061 0.012 8.Kido 8.Kido <<0.021 0.010 5.Ohta 5.Ohta <<0.008 0.017 6.Mano 6.Mano <<0.018 0.015 7.Natsui 7.Natsui <<0.061 0.012 8.Kido 8.Kido <<0.021 0.010 137 Cs discharge from rivers (April ～ September 2012)

12. 137 Cs radioactivity at “Unloading dock” inside the plant harbor Data source: TEPCO 137 Cs radioactivity at “Unloading dock” inside the plant harbor Data source: TEPCO 137 Cs radioactivity (Bq/L) Leak from the plant 137 Cs release in summer 2012 Harbor-water: 2.3 x 10 6 m 3 Exchange rate: 0.44 day -1 (6 ～ 19 April 2011) Average 137 Cs at “Unloading dock”: 9.9Bq L -1 (1 April ～ 30 September 2012) 137 Cs release in summer 2012 Harbor-water: 2.3 x 10 6 m 3 Exchange rate: 0.44 day -1 (6 ～ 19 April 2011) Average 137 Cs at “Unloading dock”: 9.9Bq L -1 (1 April ～ 30 September 2012) 10 GBq day -1 0.30 TBq month -1 0.44 day -1 9.9 Bq L -1 Unloading dock Plant harbor

13. Water volume (m 3 ) Contaminated water underneath the reactor/turbine housings of Reactors 1-4 Calculated by JK based on data released by TEPCO 137 Cs inventory (PBq) Volume 137 Cs “Highly-contaminated” water under the plant Remaining 137 Cs 156 PBq (May 2011) 3 PBq (September 2012) Processed 137 Cs 220 PBq (June 2011 ～ September 2012) Diluted by groundwater inflow Remaining 137 Cs 156 PBq (May 2011) 3 PBq (September 2012) Processed 137 Cs 220 PBq (June 2011 ～ September 2012) Diluted by groundwater inflow Possible groundwater seepage from nearby seafloor??? Possible groundwater seepage from nearby seafloor???

14. Remaining 137 Cs vs. present input in <200m coastal waters (April-September 2012) Fukushima Dai-ichi Nuclear Power Plant Seawater 15.3 TBq Sediment 93.5 TBq River water <<1.3 TBq/month River sediment 0.78 TBq/month Power plant >0.30 TBq/month

15. 1. Plankton in shallow waters? Radio-cesium in biota: where is the source? 137 Cs of plankton net samples in May 2012 from TUMSAT monitoring results 137 Cs of plankton net samples in May 2012 from TUMSAT monitoring results 137 Cs (Bq/kg-wet) Bottom depth (m) Net mesh (  m) Shallow plankton samples show higher 137 Cs activity Shallow plankton samples show higher 137 Cs activity

16. Micrograph: T. Ishimaru Ocean Biogeochemical Dynamics Jorge L. Sarmiento & Nicolas Gruber (2006) 2. Sediment? “Spider leg” hypothesis? “Spider leg” hypothesis? Mixed suspended sediment? Mixed suspended sediment? Complex mixture of materials

17. Micrograph: T. Ishimaru Ocean Biogeochemical Dynamics Jorge L. Sarmiento & Nicolas Gruber (2006) 2. Sediment? “Spider leg” hypothesis? “Spider leg” hypothesis? Mixed suspended sediment? Mixed suspended sediment? Complex mixture of materials Characterization of sediment and suspended particles are essential Characterization of sediment and suspended particles are essential

18. ―Research Topic(4) Understanding the migration and concentration of radioactive materials in marine ecosystems Principal Investigator Jota KANDA Co-Investigators Minoru KITAMURAJun NISHIKAWA Tatsuo AONOMasato MOTEKI Kotaro TSUCHIYAAtsushi YAMAGUCHI Yuji TANAKAYutaka WATANABE Shogo TAKAGIAkira NODA Toshifumi HAYASHI Cooperation Researchers Shigeharu MORIYA Cooperators Takashi ISHIMARUHiroshi YAMAKAWA Satoshi IGARASHIJiro SUGA Interdisciplinary Study on Environmental Transfer of Radionuclides from the Fukushima Daiichi NPP Accident Head Investigator Yuichi ONDA

19. Thank you so much for your research efforts and discussions regarding Fukushima