Radioactively contaminated soil: Measured by citizens
- “Is it really safe?” Cooperation of 30 citizens’ radiation measuring stations around Japan.
- The results of 1900 soil samples from 17 prefectures are available online.
It has been 5 years since TEPCO’s Fukushima Daiichi nuclear power station’s accidents. The radioactive contamination in the air has shown some decrease due to the natural process of decaying and the results of the decontamination. However, when we look at the contamination level in soil, we still find hotspots that are highly contaminated and radioactivity controlled area. They are found in East Japan. “Is it really safe?”. Some citizen who share the concerns started citizens’ radiation measuring stations around Japan. They upload the results of the measurements on their website.
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)