Ishii Yumiko, Matsuzaki Shin-Ichiro S, Hayashi Seiji
Environmental Impact Assessment Section, Fukushima Branch, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Tamura, Fukushima, 963-7700, Japan.
Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
J Environ Radioact. 2020 Mar;213:106102. doi: 10.1016/j.jenvrad.2019.106102. Epub 2019 Nov 21.
Determination of radionuclide concentration factor (CF) allows estimating the transfer of environmental radionuclides and potential risks of consuming fish contaminated with radionuclides. Although it is known that biotic and abiotic factors affect fish CF, only a few studies have examined whether these factors differ among ecosystems. We estimated radiocesium (Cs) CF of 30 different fish species and other aquatic organisms by monitoring three lakes and five rivers in Fukushima, 2-4 y after the Fukushima Dai-ichi Nuclear Power Plant accident. The relative effects of biotic and abiotic factors on Cs CF in freshwater organisms were compared between river and lake ecosystems using generalized linear models. Our analysis demonstrated the following. (1) The factors critically affecting fish CF differed between rivers and lakes. The negative effects of suspended solid concentration (SS), total organic carbon (TOC), and salinity were significant for rivers, but not for lakes. Biomagnification of Cs in piscivore fish was significant only in the lakes. (2) Fish size significantly affected the CF in both rivers and lakes. Nevertheless, the correlation between Cs concentration and piscivore fish size was stronger in lakes than in rivers. (3) The SS, TOC, and salinity simultaneously influenced the CF at every trophic level. However, feeding habit was a stronger determinant of Cs bioaccumulation than water chemistry in organisms at higher trophic levels, such as aquatic insects, amphibians, and fish. Our findings indicate that Cs accumulation in aquatic organisms is ecosystem-dependent due to different environmental factors and food web structure.
确定放射性核素浓度因子（CF）有助于估算环境放射性核素的转移以及食用受放射性核素污染鱼类的潜在风险。尽管已知生物和非生物因素会影响鱼类的CF，但只有少数研究考察了这些因素在不同生态系统中是否存在差异。在福岛第一核电站事故发生2 - 4年后，我们通过监测福岛的三个湖泊和五条河流，估算了30种不同鱼类及其他水生生物的放射性铯（Cs）CF。使用广义线性模型比较了河流和湖泊生态系统中生物和非生物因素对淡水生物中Cs CF的相对影响。我们的分析结果如下：（1）对鱼类CF有关键影响的因素在河流和湖泊之间存在差异。悬浮固体浓度（SS）、总有机碳（TOC）和盐度对河流有显著负面影响，但对湖泊没有。食鱼性鱼类中Cs的生物放大作用仅在湖泊中显著。（2）鱼类大小对河流和湖泊中的CF均有显著影响。然而，湖泊中Cs浓度与食鱼性鱼类大小的相关性强于河流。（3）SS、TOC和盐度同时影响每个营养级的CF。然而，在较高营养级的生物（如水生昆虫、两栖动物和鱼类）中，摄食习惯比水化学性质对Cs生物积累的决定作用更强。我们的研究结果表明，由于环境因素和食物网结构不同，水生生物中Cs的积累具有生态系统依赖性。
