Distribution of ¹³⁴Cs and ¹³⁷Cs radioactivity of surface soil originated in the Fukushima Dai-ichi nuclear power plant accident at Shizuoka city, Japan

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  Distribution of radioactive Cs was investigated in the surface soils of urban and vicinity areas of Shizuoka city, Japan. Concentration of ¹³⁴Cs and ¹³⁷Cs showed values in the range of 37 to 2435 Bq/m² (1 to 95 Bq/kg) and 57 to 2242 Bq/m² (2 to 98 Bq/kg), respectively. The original production ratio of ¹³⁴Cs and ¹³⁷Cs was estimated to be 1:1. The high activity areas were mainly observed along the Warashina area and southern slope of the Udo Hills. The pollutant fine particles with radioactive Cs released from the Fukushima Dai-ichi nuclear power plant were arrived at Shizuoka city by northwest wind in the morning and southwest wind in the afternoon on March 15, 2011. The radioactive Cs distribution pattern indicates that these pollutant particles were dropped on land surface of the Warashina area and southern slope of the Udo Hills during ascending wind in the afternoon on March 15, 2011.