Differences in Rates of Decrease of Environmental Radiation Dose Rates by Ground Surface Property in Fukushima City After the Fukushima Daiichi Nuclear Power Plant Accident

AbstractAfter the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

[1]  E. Peters,et al.  Ecological half-lives of 137Cs in fishes from the Savannah River Site. , 1999, Health physics.

[2]  M. Mahoney,et al.  Influence of various factors on individual radiation exposure from the chernobyl disaster , 2002, Environmental health : a global access science source.

[3]  H. Müller,et al.  Reduction of External Exposure from Deposited Chernobyl Activity by Run-Off, Weathering, Street Cleaning and Migration in the Soil , 1987 .

[4]  G. Pröhl,et al.  Ecological half-lives of 90Sr and 137Cs in terrestrial and aquatic ecosystems. , 2006, Journal of environmental radioactivity.

[5]  P. Lindop.  Biological Effects of Radiation , 1957, Nature.

[6]  Xavier Basagaña,et al.  Serum organochlorines and urinary porphyrin pattern in a population highly exposed to hexachlorobenzene , 2002, Environmental health : a global access science source.

[7]  A. Maes,et al.  Quantitative analysis of radiocaesium retention in soils , 1988, Nature.

[8]  Hiroshi Matsumura,et al.  Diffusion of Radioactive Materials from Fukushima Daiichi Nuclear Power Station Obtained by Gamma-Ray Measurements on Expressways , 2011 .

[9]  G. Kirchner,et al.  Seasonal variations in soil-to-grass transfer of fallout strontium and cesium and of potassium in North German soils , 1996 .

[10]  R. Vesanen,et al.  Patterns of chernobyl fallout in relation to local weather conditions , 1988 .

[11]  Ferdinand Steger,et al.  Ecological half-life of 137Cs in lichens in an alpine region. , 2007, Journal of environmental radioactivity.

[12]  C. Busby.  Very Low Dose Fetal Exposure to Chernobyl Contamination Resulted in Increases in Infant Leukemia in Europe and Raises Questions about Current Radiation Risk Models , 2009, International Journal of Environmental Research and Public Health.

[13]  Joseph Hilbe,et al.  A Handbook of Statistical Analyses Using R , 2006 .

[14]  U. Çevik,et al.  Ecological half-life of 137Cs in mosses and lichens in the Ordu province, Turkey by Cevik and Celik. , 2009, Journal of environmental radioactivity.

[15]  T. Kakamu,et al.  An assessment of radiation doses at an educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the nuclear accident , 2012, Environmental Health and Preventive Medicine.

[16]  Masayoshi TsujiHideyuki,et al.  An assessment of radiation doses at an educational institution 57.8 km away from the Fukushima Daiichi nuclear power plant 1 month after the nuclear accident , 2012 .

[17]  J. Peles,et al.  Ecological half-life of 137Cs in plants associated with a contaminated stream. , 2002, Journal of environmental radioactivity.