Moms’ Revolution ran an article about our monitoring center.
We would like to express our thanks for your continued support.
We appreciate that a brochure named ‘Moms’ Revolution’ covered our monitoring center.
We would like to let you know what brochure ‘Moms’ Revolution’ is, so we reprint a part of their preface.
We are striving very hard to change this world through moms’ love: ‘I would like to protect our children.’; ‘I would like to save our future.’ We intend to make the moms’ activities known to public and inform you the situations of Fukushima, Tohoku district, Northeast Kanto district and Tokyo metropolitan district, which are hardly broadcast.
The article that they ran this time represents our thoughts so well, so we introduce the article here.
Your town’s citizen monitoring station
NPO Shinjuku Yoyogi Citizen Monitoring Station
Representative Mr. Hiroyuki Kuwano
Shinjuku Yoyogi Citizen Monitoring Station continues disclosing objective measured figures, hoping that ‘ Everyone could prevent an internal exposure.’
In particular, you can see so much interest in their measurement of cesium in human urine.
On this occasion, Mr. Kuwano contributes an article about their efforts.
His catalyst of launching the monitoring station
After the nuclear disaster, I realized that I had to know the true fact in order to protect my family.
At first, I started radioactivity measurements on food at my own home, but I had come to think that if I shared the information with people, I could same many people’s lives. Therefore, I decided to start a monitoring station.
Around August 2011, I began preparing the establishment of our monitoring station, consulting Mr. Hiroaki Koide, an assistant professor at Kyoto University Research Reactor Institute and Mr. Yoshinobu Koizumi at People’s Research Institute on Energy and Environment.
I was interested in internal exposure from the planning stage, so I intended to establish a monitoring station that would specialize in an area of whole body counter. However I had come to know that we needed a very extensive facility in order to investigate internal exposure and that we could hardly do measurements with a chair-style whole body counter without any screening, so I had changed my mind and started with monitoring food.
He started monitoring human urine.
It took me a long time to be prepared for launching, and it was in April 2012 that I was able to open our monitoring station. In October 2013, we started to monitor urine. Partly because many people got interested since Tokyo Shinbun covered our activities, we had the chance to monitor urine of 281 persons until October 2014.
Chart 1 shows the aggregate results.
Although we don’t have so many examples, you can see higher figures of Fukushima’s average 0,148 Bq/kg than those of Tokyo’s and the prefectures’ next to Tokyo average 0,055Bq. (The participants were the people who voluntarily asked for monitoring, not the people whom we chose at random, so you should take it into consideration that the data are biased.)
It is difficult to summarize in statistics, but we have heard various reports of poor physical condition from some people who asked for monitoring.
You can estimate ‘quantity of radioactive cesium stored in body*’ from the measured figures of urine. According to ICRP’s ( International Commission on Radiological Protection) hypothesis, if radioactive cesium in an adult’s urine is 0,05Bq/kg, and the quantity of his/her urine a day is 1,6l, you can conclude that the quantity of cesium stored in his/her body is 14Bq/body.
Though it depends on the density of radioactive potassium 40, the minimum detectable quantity of cesium 137 in a 16-hour measurement is around 0,04Bq/kg.
At the moment, we are monitoring for free, targeting children who participate in the rest and recreation activities in ‘Okinawa Kuminosato’ and ‘Health Consultation of children’. I hope that we will be able to widen the range of our activities with other NPOs.
Food measurements are centered on the food produced by food manufacturers.
With intent to share information with a lot of people by using instruments with limited capacity, we are monitoring a series of food products made by food manufacturers which are sold on the shelves of supermarkets.
So far, we have monitored dry milk, milk, mushrooms grown in mushroom beds, tofu, yogurt and so on, and disclosed their lists. If you are interested, please have a look at our homepage and Twitter.
In addition, we have started a collaboration with an Italian restaurant ‘Elio Locanda Italiana’ (Chiyoda ward, Tokyo), in which collaboration they offer seafoods whose specific places of origin can be accurately traced and they give commentary about the results of monitoring them.
By monitoring the atmosphere, aspirated air exposure can be estimated.
We are planning to monitor radioactivities contained in floating dusts by using a ‘high-volume air sampler’ (We call it “haibori” for short. It looks like an instrument screen. It works like a vacuum cleaner. Its filters catch dusts.) At the moment, there are very few citizen monitoring stations that monitor the atmosphere. Local governments give figures, but many of them are monitoring at top of buildings, so you cannot see how the things are at the level at which pedestrians are walking. Therefore, at the moment specific data cannot be available and the risks of aspirated air exposure are not clearly recognized.
The ‘haibori’ inhales 1㎥ of air a minute. It is said that a human inhales 15㎥ of air a day, though it varies according to their lifestyle.
The ‘haibori’ inhales 480㎥ in eight hours; 10,000㎥ in a week.
We are planning to have it running as we can and monitor at as low a detection limit as possible.
We still have technological problems, but we think that we will try to solve them in consultation with Mr. Koide.
The problem is how to lower a detection limit.
We are introducing the second germanium semi-conductor detector in coming February. This germanium semi-conductor detector has a far higher performance.
Germanium semi-conductor detectors run the gamut and their performances vary greatly. Germanium semi-conductor detectors with a poor shielding (for example, they have no shielding at the bottom of them and use a lead shield which is contaminated with Pb 210.) have high level backgrounds and it is difficult to create a low detection limit with those instruments.
At the moment, in order to calculate measured figures, we are mainly using the software which Mr. Koide has made. He has proofread as well. We are using the volume source of Japan Radioisotope Association. In addition, we cross-check between several germanium semi-conductor detectors.
Judge for yourself with precise figures.
I think that things people eat and places people live in are kind of the ways they live and that people should judge for themselves. Other people shouldn’t tell them easily that it is safe or dangerous. All that citizen monitoring stations can do is give people correct figures and provide materials with which they can make judgements.
Fortunately, food contamination with radioactivity tends to decline. There are very few foods contaminated with radioactive cesium 137 that is over 1Bq/kg. If you choose carefully, internal exposures by food could be constricted to a very low level.
To protect your life, you must be careful about harmful materials such as genetically modified food, agricultural chemicals, and food additives, as well as radioactivities.
I think it important to do in a matter-of-fact way what you can in everyday life.
Not only nuclear advocates tell lies about radioactivities; some people who act as ordinary citizens are also comfortable with lying. I would like you not to accept stories on the web without questioning and assess what the truth is.