FY2014 Results of the Radioactive Material Monitoring in the Water Environment March 2016 Ministry of the Environment Contents Outline .......................................................................................................................................................... 1 Part 1: National Radioactive Material Monitoring in the Water Environment in the Whole of Japan (FY2014) ....................................................................................................................................................... 6 1. Objective and Details ............................................................................................................................ 6 1.1 Objective ......................................................................................................................................... 6 1.2 Details ............................................................................................................................................. 6 2. Survey Methods and Analysis Methods ............................................................................................. 18 2.1 Survey methods ............................................................................................................................ 18 2.2 Analysis methods .......................................................................................................................... 19 3. Results ................................................................................................................................................ 21 3.1 Detection of total β radioactivity and γ-ray emitting radionuclides ............................................... 21 (1) Public water areas ......................................................................................................................... 21 1) Water ........................................................................................................................................... 21 2) Sediments ................................................................................................................................... 23 (2) Groundwater .................................................................................................................................. 26 3.2 Consideration regarding detected radionuclides .......................................................................... 29 (1) Detection of naturally occurring radionuclides .............................................................................. 29 1) Correlation between activity concentrations of K-40 and salinity ............................................... 29 2) Uranium and thorium series radionuclides ................................................................................. 32 (2) Detection of artificial radionuclides ................................................................................................ 36 1) Cs-134 and Cs-137 in sediments................................................................................................ 36 2) Cs-134 and Cs-137 in water ....................................................................................................... 44 3) Cs-134 and Cs-137 in groundwater ............................................................................................ 44 3.3 Survey to check annual variation .................................................................................................. 45 Part 2: Radioactive Material Monitoring in the Water Environment in and around Fukushima Prefecture (FY2011 to FY2014) ................................................................................................................................... 47 1. Objective and Details .......................................................................................................................... 47 1.1 Objective ....................................................................................................................................... 47 1.2 Details ........................................................................................................................................... 47 2. Survey Methods and Analysis Methods ............................................................................................. 49 2.1 Survey methods ............................................................................................................................ 49 2.2 Analysis methods .......................................................................................................................... 49 3. Outline of the Results ......................................................................................................................... 51 3.1 Detection of radioactive cesium .................................................................................................... 51 3.2 Detection of radionuclides other than radioactive cesium ............................................................ 55 4. Results (Radioactive Cesium (Cs-134 and Cs-137)) ......................................................................... 56 4.1 Water ............................................................................................................................................. 56 (1) Public water areas ......................................................................................................................... 56 1) Rivers .......................................................................................................................................... 56 i 2) Lakes ........................................................................................................................................... 56 3) Coastal areas .............................................................................................................................. 56 (2) Groundwater .................................................................................................................................. 56 4.2 Sediments ..................................................................................................................................... 61 (1) Public water areas (rivers) ............................................................................................................. 61 (2) Public water areas (lakes) ............................................................................................................. 61 (3) Public water areas (coastal areas) ................................................................................................ 61 4.3 Detection of radioactive materials in sediments by location ......................................................... 65 (1) Evaluation policy ............................................................................................................................ 65 (2) Concentration levels in sediment samples from rivers, lakes, and coastal areas and their changes by prefecture ....................................................................................................................................... 68 (2)-1 Rivers ......................................................................................................................................... 68 (2)-2 Lakes .......................................................................................................................................... 86 (2)-3 Coastal areas ........................................................................................................................... 102 (3) Conclusion ....................................................................................................................................112 5. Results (Radionuclides Other than Radioactive Cesium) ................................................................ 121 5.1 Radioactive iodine (I-131) ........................................................................................................... 121 (1) Water ........................................................................................................................................... 121 1) Public water areas ..................................................................................................................... 121 2) Groundwater.............................................................................................................................. 121 (2) Sediments .................................................................................................................................... 121 5.2 Radioactive strontium (Sr-90 and Sr-89) .................................................................................... 124 (1) Public water areas ....................................................................................................................... 124 (2) Groundwater ................................................................................................................................ 127 5.3 Other γ-ray emitting radionuclides .............................................................................................. 128 Part 3: Other Radioactive Material Monitoring Conducted Nationwide (FY2014) ................................... 132 1. Outline of the Monitoring .................................................................................................................. 132 1.1 Covered monitoring ....................................................................................................................