A handbook of environmental toxicology: human disorders and ecotoxicology.

Chapter 34 (Page no: 497)

Fukushima nuclear accident: potential health effects inferred from butterfly and human cases.

Fukushima Dai-ichi Nuclear Power Plant released massive amounts of radioactive materials in 2011, resulting in environmental pollution in the Tohoku-Kanto districts of Japan. Biological effects of this nuclear accident have been examined using the pale grass blue butterfly, Zizeeria maha, as an environmental indicator species that is amenable to both field and laboratory studies. In this chapter, on the basis of the butterfly results, low-dose effects are discussed from biological perspectives that are not dependent on the conventional dose-centric view. Advantages of using this butterfly are that it can monitor the human-living environment and thus help to infer effects of environmental pollution on human health. Pronounced ingestional toxicity of contaminated diets at low radiation levels on this butterfly likely originated not only from the 'direct' ionization mechanism in the butterfly, but also from multiple 'indirect' mechanisms, including physical and immunological damage from insoluble particles and naturally occurring dust to which radioactive materials are attached and nutritional deficiencies or plant-derived chemical poisoning in the polluted hostplant leaves. These unconventional indirect effects cannot be readily predicted by dosimetry, because most of them are field effects mediated by field substances and species interactions. To illustrate a possible unconventional effect on humans, a case is presented here of patient 'C.U.', who developed systemic oedema and was medically diagnosed as nephrotic syndrome. Retrospectively, she was likely sensitized by nuclear dust in her repeated visits to Fukushima; and then her exposures in Okinawa to minute amounts of the dust from Fukushima preceded acute increases of her body weight, an objective indicator for disease progression, suggesting an essential role of the contaminants for her health problem at very low doses. Taken together, butterfly and human cases suggest that pollutants released by the Fukushima nuclear accident caused harmful impacts on organisms through unconventional indirect mechanisms.

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