Detail of Grant Awarded General Researches
Relationship between Rainwater Flow and Radioactive Contamination of the Soil and Fauna and Flora in the Middle Reaches of the Tama River and Its Tributary Areas
(at that time)
|Chairman, Non-Profit Organization R. I. La|
Radioactive materials from the Fukushima Daiichi nuclear accident, caused by the Great East Japan Earthquake in March 2011, spread not only in Fukushima Prefecture but also throughout the Kanto region. Not surprisingly, Tokyo is not an exception. In the Tama River watershed, there still remain many “hot spots” where high radiation dosages are found. Of the rivers in the Tama area, in the two-year research of air dosage done at the Karabori River flowing through Higashiyamato City in Tokyo, where our non-profit organization R. I. La is located, we found a close relationship between the rainwater flow from urban areas and the radioactive contamination of the river water. Also for the Tama River watershed, an environment-related civil group in Musashi-Murayama City has reported a similar result for the Zambori River that flows into the lower reaches of the Tama River at Tappi Bridge in Tachikawa City. Thus we have collected soil samples from these spots where rainwater from urban areas flows into riverbeds in the middle reaches of the Tama River and its tributary areas, and measured their radiation levels.
As the result of the survey, we detected, in the soils at the riverbeds, around embankments, and riversides of the Tama River’s middle reaches (between Hino Intake Weir and Hino Bridge) and the Zambori River (the Tama River’s tributary), notably high amount of radioactive nuclides, especially at those spots where rainwater from the urban areas flows into the rivers, compared to other spots. We identified those spots as special spots in regard to the radioactive contamination of soil, and have made a map of these areas showing their measured air and soil dosages.
Noriyuki Itoh (Director, Non-Profit Organization R. I. La), Manami Uchino, Misako Ozaki, Yoko Matsuda
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