著者

Rei YAMASHITA Michio MURAKAMI Yuichi IWASAKI Nao SHIBAYAMA Keisuke SUEKI Mahua SAHA Goro MOURI Soulichan LAMXAY Haechong O Yukio KOIBUCHI Hideshige TAKADA

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.13, no.2, pp.179-194, 2015 (Released:2015-04-10)

参考文献数

49

被引用文献数

3 15

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The release of radiocesium from the Fukushima Dai-ichi Nuclear Power Plant caused environmental contamination. We analyzed sources, behavior, and temporal trends of radiocesium by 1-year monitoring in an urban river, the Ohori River. The concentrations of 137Cs in both particulate and dissolved phases decreased to ~ 16% within 1 year. The partition coefficient in dry weather was estimated to be 3.2 × 104 L/kg. 137Cs concentrations in the particulate phase were higher during wet weather than during dry weather on the basis of both suspended solids (SS) weight and liquid volume. The ratios of 137Cs concentration to deposited 137Cs in the Ohori River (e.g., composite: 0.26 m2/kg-SS in June - July 2012) were higher than those in the Abukuma River, probably because of differences in land use. Source analysis by a chemical mass balance method showed that 22% of 137Cs came from river water in dry weather, 39% from river sediments, and 39% from road dust highlighting urban surface deposits such as road dust as major sources of 137Cs in the river water even 2 years after the accident, and that the wash-off of these deposits increased the 137Cs concentration in the river during wet weather.