Radioactively
contaminated soil: Measured by citizens
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“Is
it really safe?” Cooperation of 30 citizens’ radiation measuring stations
around Japan.
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The
results of 1900 soil samples from 17 prefectures are available online.
In October
2015, “Measuring Becquerel level in Soil Project in East Japan” has started
(There are three co-founders including Hiromi Abe who is the chief director of
Fukushima 30 years project). They have
measured more than 1900 soil samples from people’s habitat zone in 17
prefectures of East Japan. All the samples are gathered in the standardized
way. The results of the data are released on their website.
The purpose
was to measure the mean of the contamination level for the region. Therefore,
they excluded areas that are highly contaminated. Secretary general Hidetake
Ishimaru said “We would like to avoid presenting misreading data of the general
contamination level of a region with one peculiarly highly contaminated data.
We can gain some ideas of where to be cautious about by having one standardized
measurement that can be compared with each other”.
The highest
contamination found so far is from a soil sample from a copse near a house in
Iidate village. In total of 135000 Becquerel of cesium was found (111028
Becquerel of cesium 137 and 23920 Becquerel of cesium 134). The contamination
level decreases when measuring samples from Sizuoka prefecture. However, there
are soil samples that are contaminated more than 10,000 Becquerel in Kanto
area.
30
citizens’ radiation measuring stations around Japan are taking part in the
project. Among all the stations, a station from Iwate prefecture “Protecting
children from exposure to radiation: Iwate” was the first one who started
measuring the soil samples. One year after the nuclear power stations’
accidents, they started measuring contamination in soil and air mainly of
schools and parks within the prefecture. They have gathered and released 316
data already.
Chief
director Kazuhiro Sugawara (39 years old) was a chairman of PTA for his
daughter’s primary school when the accident had occurred. The main debate among
the parents after the accident was “whether it is safe to let their children
play outside”. The government had been
announcing that it is safe based on the results of air contamination, but the
risk was measured based on the contamination levels of soil in the case of
Chernobyl. After he found that out, they started measuring soil, saying “if the
government is not measuring the soil, then we have to do it by ourselves”.
“Children
play touching the soil, and they wipe their mouth with the hands. They inhale
the dust that are blown by wind. Those are all the risks of getting internally
exposed to the radiation. We cannot feel safe without knowing the results of
soil contamination levels”.
The highest
radioactive contamination they have detected was from Kanegasaki, Iwate in June
2012. The air pollution was 0.24 mSv/h, but the soil contamination was more
than 4500 Becquerel.
Cost for
measuring a sample is about ¥ 2,000. In the project the soil samples are
measured for free, and the expense is covered by donation from citizens and
funding from some companies.
There are
still not enough samples from Niigata, Tochigi and Gunma prefectures. Secretary
general Ishimaru said “Those prefectures are all famous for their farm land.
Some people are scared of ‘harmful rumors’, so they are reluctant to join our
project.” They are holding lectures targeting citizens to raise their
understanding of the project in those three prefectures.
Researcher
of nuclear power station from Kyoto University Tetsuji Imanaka who has been
investigating and measuring the soil contamination mainly within Fukushima
prefecture said “Results of soil contaminations are the base data for analyzing
the contamination level in the region. Thus, it needs to be investigated and
measured as precisely as it can be. It is actually government’s responsibility
to do so, but I am looking forward to the outcomes from the project”.
(written by
Masakazu Honda)
