| Autor: |
Haque, M. E., Gomi, T., Sakai, M., Negishi, J. N. |
| Předmět: |
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| Zdroj: |
Landscape & Ecological Engineering; Jan2018, Vol. 14 Issue 1, p45-53, 9p |
| Abstrakt: |
The seasonal variability of food web-based transfer factors (TFweb) of radiocesium (137Cs) in white-spotted char (Salvelinus leucomaenis) was examined in the 2nd and 3rd year after the Fukushima Daiichi Nuclear Power Plant accident. Two headwater streams with similar landscape characteristics, but different amounts of fallout, were selected in Fukushima and Gunma Prefectures, Japan. The TFweb of predator–prey systems was based on the dietary contributions of prey items estimated from stable isotopes compared to their respective 137Cs activity concentrations. Char consumed more terrestrial food sources with higher contamination levels in summer than in winter based on their dietary-based 137Cs contributions. The TFweb values in Fukushima and Gunma in all seasons indicated 137Cs bioaccumulation from prey to predator. The TFweb in Gunma exhibited significant seasonal variation; the greatest values were observed in winter, while the lowest values were observed in summer. In contrast, the seasonal TFweb in Fukushima did not vary seasonally. Despite similar consumption patterns and the specific metabolic rates of char, the different seasonal patterns of TFweb at the two sites can be explained by the relative excretion rate with respect to the concentration of 137Cs consumed. 137Cs levels can remain relatively constant in the char body throughout the year in areas with high contamination, such as Fukushima, possibly because 137Cs intake overwhelms the excretion rate. Examining seasonal patterns in the transfer processes of 137Cs in white-spotted char are essential for understanding mechanisms of 137Cs accumulation in aquatic biota. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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