title: Uptake and retention of radio-caesium in earthworms cultured in soil contaminated by the Fukushima nuclear power plant accident.
abstract: To understand the effects of radionuclides on non-human biota and the environment, it is essential to study the intake and metabolism of radio-isotopes in earthworms which are among the most important soil organisms, and Eisenia fetida, which were used in this study, are known to be sufficiently sensitive to chemicals and representative of common earthworms. In this study, we assessed the concentration ratios, uptake and retention, absorbed dose rate, and distribution of radio-caesium in earthworms. The concentration ratios of (137)Cs (i.e., the concentrations of radio-caesium in earthworms relative to those in dry soil) were higher early in the culturing period and decreased gradually over the experimental period. (137)Cs taken up by E. fetida was cleared rapidly after the worms were cultured in radio-caesium-free soil, suggesting that the metabolism of radio-caesium in earthworms is very rapid. Autoradiography demonstrated that the concentration of radio-caesium within the digestive tract was as high as that in the soil, while radio-caesium in the body tissue was lower than radio-caesium in the soil and was almost uniformly distributed among earthworm tissues. The highest absorbed dose rate of total exposure to radio-caesium ((137)Cs + (134)Cs) was calculated to be 1.9 × 10(3) (μGy/day) in the earthworms.
authors.affiliation: Radiation Safety and Control Department of Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan. Electronic address: fujiwara@rri.kyoto-u.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Fujiwara
authors.affiliation: Radiation Safety and Control Department of Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Radiation Safety and Control Department of Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: P
authors.initials: P
authors.lastname: Nguyen
authors.affiliation: National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: Kyorin University, Miyashita-cho, Hachioji-shi, Tokyo 192-8508 Japan.
authors.forename: S
authors.initials: S
authors.lastname: Gamou
authors.affiliation: Osaka Prefecture University, Gakuen-cho, Nakaku, Sakai, Osaka 599-8531, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sakurai
authors.affiliation: Radiation Safety and Control Department of Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D002588:Cesium Radioisotopes / Q000378:metabolism*; D062406:Fukushima Nuclear Accident; D055848:Nuclear Power Plants; D009835:Oligochaeta / Q000378:metabolism*
chemical_list: D002588:Cesium Radioisotopes
keywords: Earthworm; Fukushima nuclear power plant accident; Radio-cesium; Soil