環境

一般研究成果リスト

Detail of Grant Awarded General Researches

Project

Radioactive Contamination of Soil around the Middle Reaches of the Tama River and Its Tributaries, and the Biological Impact Thereof

General
Research
No.228
Principal
Investigator
Shoko Amemiya
Affiliation
(at that time)
Chairperson, Nonprofit Organization R. I. La
Research
Summary

Radioactive materials arising from the accident at Fukushima Daiichi Nuclear Power Plant that was triggered by the Great East Japan Earthquake in March 2011 rained down not only on Fukushima Prefecture, but also on the whole of the Kanto region. Naturally, Tokyo was no exception, so there are still what are called “hot spots” — areas with a high radioactive dose — in various parts of the Tama River basin. A survey conducted last year concerning the relationship between the radioactive contamination of soil in the watershed around the middle reaches of the Tama River and inflows of rainwater identified a strong relationship between inflows of rainwater from urban areas and the radioactive contamination of rivers in the Tama area. Accordingly, we measured radiation in the common carp (Cyprinus carpio) and a number of plant species — Japanese mugwort (Artemisia princeps), long-stamen chive (Allium macrostemon), dandelion (Taraxacum), and both the sterile and fertile stems of the field horsetail (Equisetum arvense) — living on the river terraces in the middle reaches of the Tama River and its tributaries and in the soil that provides a habitat for those species.

As a result, in relation to the fact that the soil in the river terrace had a lower dose than soil in the urban area, we did not detect any radionuclides arising from the accident at Fukushima Daiichi Nuclear Power Plant in plants from the river terrace in question, but did detect some traces of the radionuclide radiocesium in common carp.


Collaborators

Noriyuki Itoh, Director, Nonprofit Organization R. I. La


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