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Temporal Changes in ¹³⁷Cs Concentrations in Fish, Sediments, And Seawater off Fukushima Japan

Wang, Cuiyu, Cerrato, Robert M., Fisher, Nicholas S.
Environmental science & technology 2018 v.52 no.22 pp. 13119-13126
accidents, cesium, detection limit, diet, invertebrates, laboratory experimentation, marine sediments, pelagic fish, radionuclides, seawater, temporal variation, Japan
We analyzed publicly available data of Fukushima ¹³⁷Cs concentrations in coastal fish, in surface and bottom waters, and in surface marine sediments and found that within the first year of the accident pelagic fish lost ¹³⁷Cs at much faster rates (mean of ∼1.3% d–¹) than benthic fish (mean of ∼0.1% d–¹), with benthopelagic fish having intermediate loss rates (mean of ∼0.2% d–¹). The loss rates of ¹³⁷Cs in benthic fish in the first year were more comparable to the decline of ¹³⁷Cs concentrations in sediments (0.03% d–¹), and the declines in pelagic fish were more comparable to the declines in seawater. Retention patterns of ¹³⁷Cs in pelagic fish were comparable to that in laboratory studies of fish in which there were no sustained ¹³⁷Cs sources, whereas the benthopelagic and benthic fish species retained ¹³⁷Cs to a greater extent, consistent with the idea that there is a sustained additional ¹³⁷Cs source for these fish. These field data, based on 13 511 data points in which ¹³⁷Cs was above the detection limit, are consistent with conclusions from laboratory experiments that demonstrate that benthic fish can acquire ¹³⁷Cs from sediments, primarily through benthic invertebrates that contribute to the diet of these fish.