Readings of Environmental Radiation Monitoring of River Water, etc. (Tritium) May 21, 2012 Nuclear Emergency Response Headquarters (Radioactivity Team) Disaster Provision Main Office of Fukushima Pref. (Nuclear Power Team) 1 Monitoring period Tuesday, November 15 – Thursday, December 15, 2011 2 Number of monitoring locations 51 locations (river water, 35 locations; lake/dam water, 13 locations; drinking water, 3 locations) 3 Monitoring results (1) Tritium ※1 (Unit: Bq/L) Reference Monitoring results Monitoring results in 2002 by Usual national data this time Fukushima Prefecture (*1) (from 2000 to2011) (*2) River water Not detected – 1.5 Not detected – 0.90 Not detected – 1.7 Lake water 0.39 – 1.6 Not detected – 0.62 Not detected – 3 Drinking water Not detected – 1.4 0.47 – 0.93 Not detected – 2.1 Source: *1 Report on monitoring for tritium in the environmental samples in 2002 (Environmental Radioactivity Monitoring Center of Fukushima) *2 Environment radiation data base (reading of environmental radioactivity level) (Japan Chemical Analysis Center) ※1 Tritium: An isotope of hydrogen which is easily absorbed into the body mainly via water. It is a beta- emitting radionuclide, and its half-life period is approximately 12 years. It occurs in nature due to nuclear reaction caused by cosmic rays . (2) Cesium 134, Cesium 137 Not detected in any locations 4. Considerations Comparing the results of this monitoring survey and those of the past survey on tritium conducted in FY2002, certain changes were observed in measured values at some points, but all the values obtained through this monitoring were within the range of nationwide data before the accident. A small amount of tritium was detected as a result of the nuclide analysis of drinking water samples. However, committed effective doses,※2 based on the supposition that infants and adults continue to take in one liter and 1.65 liters of this water containing tritium per day, respectively, for a whole year, are assessed to be around 0.000025 mSv for infants and around 0.000015 mSv for adults, which are extremely small, being less than 1/40,000 of the annual permissible dose (1 mSv). ※2 Committed effective doses: Radiation exposure levels due to radioactive substances taken into the body, specifically radiation doses accumulated from the time of the intake until becoming 70 years old for infants and radiation doses accumulated for 50 years from the time of the intake for adults (Inquiries: Monitoring Team, Radioactivity Team Tel: 024-521-1917) Readings of Environmental Radiation Monitoring of River Water, etc. (Tritium) May 21, 2012 Nuclear Emergency Response Headquarters (Radioactivity Team) Disaster Provision Main Office of Fukushima Pref. (Nuclear Power Team) ○ River water Analysis result Sampling Radioactive tritium Radioactive cesium No. Region Name of river Sampling point date H-3 (Bq/L) Cs-134 Cs-137 New survey Survey in 2002 (Bq/L) (Bq/L) Upper stream of the Tatenokoshi 1 Hirose River 2011/11/29 0.57 0.48 Not Detectable Not Detectable Bridge Before the confluence of the 2 Matsu River 2011/11/16 0.66 Not Detectable Not Detectable Not Detectable Ken-poku Abukuma River 3 Utsushi River Ozegawa Bridge 2011/11/26 Not Detectable 0.51 Not Detectable Not Detectable 4 Yuigawa River Yuigawa Bridge 2011/12/13 0.46 0.46 Not Detectable Not Detectable After the confluence of the 5 Gobyaku River 2011/11/23 0.46 0.46 Not Detectable Not Detectable Ishimushiro River 6 Otakine River Funehiki Bridge 2011/11/28 Not Detectable 0.55 Not Detectable Not Detectable 7 Yatagawa River Yatagawa Bridge 2011/11/24 1.5 Not Detectable Not Detectable Not Detectable 8 Namekawa River Old Route 4 2011/12/13 0.39 0.46 Not Detectable Not Detectable Ken-chu Shakadokawa Tap water intake point for Sukagawa 9 2011/11/25 1.1 Not Detectable Not Detectable Not Detectable River City 10 Abukuma River Emochi Bridge 2011/11/24 0.38 Not Detectable Not Detectable Not Detectable 11 Imade River Nekonaki Bridge 2011/11/24 0.38 Not Detectable Not Detectable Not Detectable 12 Natsui River Kitanouchi Bridge 2011/11/29 0.39 0.56 Not Detectable Not Detectable 13 Yashirogawa River Yashirogawa Bridge 2011/11/25 Not Detectable 0.56 Not Detectable Not Detectable 14 Ken-nan Kuji River Matsuoka Bridge 2011/11/25 0.47 Not Detectable Not Detectable Not Detectable Before the confluence of the Kuji 15 Kawakami River 2011/12/13 0.40 Not Detectable Not Detectable Not Detectable River 16 Old Miyakawa River Jyosuke Bridge 2011/11/19 0.36 0.90 Not Detectable Not Detectable Aizu 17 Nigori River Nigorikawa Bridge 2011/11/15 0.60 0.57 Not Detectable Not Detectable 18 Minamiaizu Agano River Tajima Bridge 2011/11/15 0.36 0.46 Not Detectable Not Detectable Hamahata Bridge (Old 19 Jizou River 2011/11/23 Not Detectable 0.77 Not Detectable Not Detectable Yamazakimae Bridge) 20 Koizumi River Koizumi Bridge 2011/11/24 0.69 0.64 Not Detectable Not Detectable 21 Uda River Horisaka Bridge 2011/11/24 0.61 0.48 Not Detectable Not Detectable Sousou 22 Mano River Ochiai Bridge 2011/11/29 0.59 0.75 Not Detectable Not Detectable 23 Niida River Kidouchi Bridge 2011/11/29 0.93 0.81 Not Detectable Not Detectable 24 Ota River Maruyama Bridge 2011/11/21 0.38 0.50 Not Detectable Not Detectable 25 Odaka River Zencho Bridge 2011/11/21 0.84 0.64 Not Detectable Not Detectable 26 Ohisa River Kageiso Bridge 2011/11/23 0.85 Not Detectable Not Detectable Not Detectable 27 Kohisa River Rengo Bridge 2011/11/23 0.46 Not Detectable Not Detectable Not Detectable 28 Yoshima River Iwaana suspension bridge 2011/11/23 1.0 Not Detectable Not Detectable Not Detectable 29 Arakawa River Furukawa Bridge 2011/12/14 0.65 Not Detectable Not Detectable Not Detectable 30 Niida River Kasumida Bridge 2011/11/23 0.63 Not Detectable Not Detectable Not Detectable Iwaki 31 Fujiwara River Minato Ohashi Bridge 2011/11/26 0.34 Not Detectable Not Detectable Not Detectable 32 Yatagawa River Yatagawa Bridge 2011/12/14 0.69 Not Detectable Not Detectable Not Detectable 33 Samegawa River Idozawa Bridge 2011/11/22 0.50 Not Detectable Not Detectable Not Detectable Before the confluence of the 34 Shitoki River 2011/12/14 0.87 0.60 Not Detectable Not Detectable Samegawa River 35 Binda River Kobana Bridge 2011/11/26 0.85 Not Detectable Not Detectable Not Detectable ○ Lake/dam water Analysis result Name of lakes Sampling Radioactive tritium Radioactive cesium No. Region Sampling point and dams date H-3 (Bq/L) Cs-134 Cs-137 New survey Survey in 2002 (Bq/L) (Bq/L) 36 Handanuma Center of lake 2011/11/16 1.1 0.49 Not Detectable Not Detectable Ken-poku Center of lake (Upper Layer) 2011/11/30 0.43 ― Not Detectable Not Detectable 37 Surikami Dam Center of lake (Lower Layer) 2011/11/30 0.46 ― Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/29 1.6 Not Detectable Not Detectable Not Detectable 38 Miharu Dam Center of lake (Lower Layer) 2011/11/29 0.69 ― Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/22 0.53 Not Detectable Not Detectable Not Detectable 39 Ken-chu Hatori Dam Center of lake (Lower Layer) 2011/11/22 0.54 ― Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/24 0.90 0.54 Not Detectable Not Detectable 40 Sengozawa Dam Center of lake (Lower Layer) 2011/11/24 1.2 ― Not Detectable Not Detectable 41 Ken-nan Nanko Lake Center of lake 2011/11/26 0.60 0.49 Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/23 0.89 Not Detectable Not Detectable Not Detectable 42 Lake Hibara Center of lake (Lower Layer) 2011/11/23 0.99 ― Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/19 0.65 0.48 Not Detectable Not Detectable 43 Aizu Inawashiro Lake Center of lake (Lower Layer) 2011/11/19 0.45 ― Not Detectable Not Detectable Higashiyama Center of lake (Upper Layer) 2011/11/16 0.65 ― Not Detectable Not Detectable 44 Dam Center of lake (Lower Layer) 2011/11/16 0.53 ― Not Detectable Not Detectable 45 Mano Dam Center of lake 2011/11/24 0.90 0.41 Not Detectable Not Detectable Sousou 46 Takanokura Dam Center of lake 2011/11/28 1.0 Not Detectable Not Detectable Not Detectable Center of lake (Upper Layer) 2011/11/24 0.41 0.62 Not Detectable Not Detectable 47 Kodama Dam Center of lake (Lower Layer) 2011/11/24 0.66 ― Not Detectable Not Detectable Iwaki Center of lake (Upper Layer) 2011/11/22 0.39 0.51 Not Detectable Not Detectable 48 Shitoki Dam Center of lake (Lower Layer) 2011/11/22 1.1 ― Not Detectable Not Detectable ○ Drinking Water Analysis result Sampling Radioactive tritium Radioactive cesium No. Region Municipality Sampling point date H-3 (Bq/L) Cs-134 Cs-137 New survey Survey in 2002 (Bq/L) (Bq/L) 49 Ken-poku Fukushima City Nuclear Center Fukushima branch 2011/12/15 1.2 0.79～0.93 Not Detectable Not Detectable Aizuwakamatsu Aizuwakamatsu joint government 50 Aizu 2011/11/29 1.4 0.68～0.82 Not Detectable Not Detectable City building 51 Sousou Hirono Town Futatsu-numa Park 2011/12/15 Not Detectable 0.47～0.73 Not Detectable Not Detectable * "Not Detectable" indicates the case that the detected radioactive concentration in this analysis was lower than the detection limits (Tritium: approximately 0.35 Bq/L, Cesium 134 and 137: approximately 2 Bq/L).