The role of autochthonous organic matter in radioactive cesium accumulation to riverine fine sediments

WATER RESEARCH

卷:137

Article

Fujii, Manabu¹  Ono, Keisuke¹  Yoshimura, Chihiro¹  Miyamoto, Manami¹ 

[1] Tokyo Inst Technol, Dept Civil & Environm Engn, 2-12-1-M1-4 Ookayama, Tokyo 1528552, Japan

关键词: Radioactive cesium;    Riverine fine sediments;    Allochthonous organic matters;    Fukushima Daiichi Nuclear Power Plant;   

DOI  :  10.1016/j.watres.2018.02.063

来源: Elsevier

【 摘 要 】

Anthropogenically released radioactive cesium (RCs) poses serious ecological and environmental concerns given its persistency in the environment. Although accumulation of RCs in aqueous and sedimentary environments is often reported to associate with organic matter (OM), the mechanisms responsible remain unclear. Here, we investigated RCs in fine sediments along the Abukuma River, the largest river near the Fukushima Daiichi Nuclear Power Plant, 1.5-4 years after the accident. Measuring the density-separated sediment fractions with a broad range of OM content (%) indicated that the RCs concentration (Bq.kg(-1)) is positively correlated with OM content for intermediate-density fractions in which OM is primarily characterized by autochthonous origin. This relationship, however, did not hold for light-density fractions containing a high proportion of large-size allochthonous OM. Furthermore, H2O2-assisted OM digestion and amorphous material dissolution treatments resulted in only a minor reduction in sedimentary RCs. These results along with the fact that sediments with high autochthonous OM content showed high specific surface area indicated that RCs is tightly associated with finer-grained and chemically non-labile inorganic fractions concurrently resident with autochthonous OM. Overall, our findings highlight that autochthonous OM exerts a significant control on the accumulation, transport, and fate of RCs in aqueous and sedimentary environments. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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