Posts Tagged ‘Strontium’

This post is an update of Geiger Counter Case Study: Inspector Alert published on SurvivalJapan in which some questions remained open, mainly about the relatively high values (although still in the safe range) which I measured with the system kindly lent to me by Safecast and from whom I received some further advice.

The Safecast bGeigie system is designed to measure mainly gamma rays (high energy protons, akin to X-rays) and hence is used at least one meter above ground in their radiation maps. Since I live in the monitored land, several hundred miles away from Fukushima, gamma radiation is low and not really a concern. Therefore I had measured instead beta radiation (high energy electrons or positrons which are emitted back from the ground after radioactive fall-out) at about one foot above ground. For convenience, I monitored the level of radiation with the Safecast display which communicates by radio with the Inspector Alert safely cast in its lunchbox style (in Japanese “bento”) box, along with the GPS and SD memory card to geo-locate and store results. The Safecast team advised against this methodology for beta radiation pick-up and advised me to use the Inspector Alert alone for that matter – which I did.

I read the user manual to set the Inspector Alert display in uSv/h as opposed to CPM (count per minute) as I am more familiar with this unit and it is more relevant for body effects. The user manual explains that the factor used by the device to convert CPM into uSv/h is based on Cesium-137, the radionuclide used for its calibration, so the uSv/hr display is less accurate for other nuclides (such as Cesium-134, Strontium-90, Iodine-131 and of course Uranium and Plutonium…). This is why Safecast uses the CPM raw data instead.

The first measure that I made was inside my home and the display changed widely even in a single place. A Geiger counter is not like a weighing scale: it does not give a result at once nor does it give a stable result. Therefore when a value is broadcast either by citizens or a governmental organization, it should be taken with a grain of salt. For instance, I could measure 0.120 uSv/h and any value between 0.090 and 0.150 uSv/h, that is about 25% more or less than the central value. Sometimes, some wilder values would come up: how do we interpret these?

Radiation is a random phenomenon which occurs naturally, so when a particle hits the Geiger counter sensor plate, it is registered and changes the overall measure value. The Inspector Alert averages measures over 30 seconds in order to get a more statistically relevant measure. Even then, the result is only displayed every 3 seconds so if one is moving, there is a delay between the measure and the display. Then there is the 15% accuracy which is probably an average: it means that some wild values (standard deviation) can occur from time to time. Other factors which can affect the results are solar flares (there was just a sunstorm by the way) and, probably, thermal drift if the device electronics is not properly compensated when temperature changes (any kind of electronics sensor is subject to this phenomenon). The bottom line is that measures could be twice as high depending on temperature, solar activity, randomness of natural radioactivity, types of radionuclides (including artificial ones from nuclear plants) and radiation (here it is a synthetic result of alpha, beta, gamma and X-rays), accuracy, resolution, etc.

Indeed, I could still measure inside and outside values from 0.055 to 0.225 uSv/h and even up to 0.355 uSv/h when spot on granite blocks which are naturally radioactive. These new measures were consistent with the range I had already measured with the full Safecast system. I could also check that the outer casing of Safecast suitcase and bento box did not emit stronger radiation than the room so the Geiger counter is likely not contaminated (and there should not be any calibration issue either according to the user manual).

I still could not double-check with another type of Geiger counter yet but these new results convinced me that they are normal. The maximum international value (except in post-Fukushima Japan) accepted is 1 mSv/year, which equates to 0.114 uSv/h. Given a 15% accuracy, it means that the Inspector Alert should read between 0.097 and 0.131 uSv/h which is indeed what it does most of the time (so we can dismiss occasional lower and higher results as products of standard deviation).

A final word of advice which I received from Safecast and which is also documented in the user manual is to use the timed count function of the Inspector Alert over at least 10 minutes to further smooth out results. There should be about 15% difference maximum between two such timed counts.

I hope that this update helps you to get a better idea about the capabilities and limitations of Geiger counters in general and specifically of the Inspector Alert – and of the analytical mindset and of the basic radiation knowledge necessary to properly use them. In any case, purchasing a Geiger counter to try and measure radioactivity in food does not make any sense (unless the food is irradiated to such a level that just staring at it is dangerous) and that monitoring the food trace is a safer and more reliable procedure. Thankfully, this is getting easier.

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Several officials reportedly had some severe health problems which turned out to be lung diseases. Fukushima fall-out regularly visits Tokyo where evermore hotspots appear and get difficult to cover up by the authorities with “non-Fukushima related” statements. Blogs and twits regularly point out to the logical existence of radionuclides which are not officially monitored until they eventually get into mainstream news, as in the case of strontium and probably “soon” uranium and plutonium oxides – how soon largely depends on when citizens will find and get a lab a positive sample that will force the authorities to admit it.

Effects on lungs are somewhat controversial as with any radioactive hazard studied and reported by governmental agencies and the nuclear industry and academia. For instance, uranium has supposedly “No adverse health effects reported” on humans whereas it causes “Severe nasal congestion and hemorrage (sic), lung lesions and fibrosis, edema and swelling, lung cancer” on animals, according to Wikipedia. As humans are ordinary animals, there is no particular reason for this discrepancy besides the political need to support their participation to the nuclear industry. Likewise, some Fukushima workers supposedly within the irradiation norms died suddenly from “non-Fukushima related” causes diagnosed by doctors working for TEPCO, under the seal of privacy and without any advanced nor official research. For instance, Fukushima Diary reported in their “Two sludge disposal facilities workers had sudden death within 2 weeks” post that, during an emergency citizen conference held on 10/24/2011 to discuss about how to deal with the radioactive debris and sewage sludge from Fukushima, the fact that two sludge disposal facilities workers died all of a sudden only in two weeks in October was leaked by a worker at a sewage farm in Chiba. This information did not appear at first in mainstream news according to blogger M. Mochizuki. Then a third worker suddenly died, supposedly from septic shock, as he reported in his subsequent post, “The third dead worker [septic shock]“. Although it is not clear whether the article refers to the same ″third″ worker (age and date differ), the Independent, a UK mainstream newspaper, reported that the worker died on his second day of work, while being exposed to “only” 170 uSv on the day he died (no mention about his first day). The Independent mentions also that: “The Japanese government’s maximum level of exposure for male workers at the plant is 250 millisieverts for the duration of the effort to bring it under control.”, which is largely over 20 millisieverts usually tolerated in other countries. Even this latter limit, which is equivalent to about 50 uSv per day, is arbitrary, as there is no reason why a nuclear plant worker should be more resistant to radiation than the general public, for which the international limit is 1 millisievert (raised to 20 in Japan after Fukushima). If we dismiss TEPCO’s explanation for the death of this worker, it seems that “fairly low” levels of radiation, contrarily to official, academic and industrial reports which serve the same community, could kill in a single day. After all, this third worker was irradiated to a daily level sixty times higher than the maximum for a member of the general public on the day he died, and no data was published for the previous day, which could be ten times more for what we know, considered the levels of radioactivity on site and other information leaked on Twitter by workers.

Although on the paper uranium and plutonium oxides are almost completely evacuated by the human body when ingested, and that when inhaled in “small” amounts, they have not been proved to be lethal, it may cast some reasonable doubts when some official people get pneumonia or bronchitis during an exceptional warm autumn, and their place of work or residence happen to be reported as some of the hottest spots in Tokyo, and that they have visited extensively Fukushima and contaminated prefectures such as Iwate and Miyagi.

Fukushima Diary reported on October 1st that some of the worse hotspots were in found in the “mud in Diet” (0.5 uSv/h) and in front of the Imperial Palace (0.7 uSv/h). Natural background radiation is ten times less. In the same post, M. Mochizuki mentioned that Upper House President Takeo Nishioka (who died of pneumonia early Saturday) nearly fainted at the Diet, that he said that he was suffering from severe canker sore and that he could not sleep recently. Besides, M. Mochizuki reported that M. Nishioka sometimes lost his words at the Diet. Of course, we may dismiss any information or connection with Fukushima as M. Nishioka was already 75 years old and some hotter spots have been found since without any casualty reported. However, when 9 year-old Princess Aiko was taken to the hospital for a cold, I suspected that it was in fact a symptom of low radiation exposure, especially since she is young and therefore more sensitive. These days, the official version from the Imperial Household Agency (IHA) is that she, like M. Nishioka, caught pneumonia. The Diet and Imperial Palace are geographically close in Tokyo. Although I hope that, now that she has left the hospital, she will live on healthily, I would not be surprised if the IHA announced some “unexpected” complications. The members of the Imperial Family must be exemplary and the Imperial couple visited Fukushima, Iwate and Miyagi two months after the nuclear disaster. Now, Emperor Akihito, who has “a fever due to a cold”, contracted bronchitis and had to go to the hospital. His immune system seems weakened, as “he appears to be fatigued and has lost some resistance to fight his illness” – which can be caused by a number of afflictions, including low-level radiation exposure, exacerbated by his old age (77). When he will die, it could be a signal for the Japanese Self-Defense Force to start a coup (Cf. Risk Of Coup In Japan? in SurvivalJapan). It would be quite a scandal if the Emperor was to become the victim of TEPCO and the government, the final straw that could very well serve as an excuse for the ultra-nationalist militaries to grab power.

These speculations will need to stand the test of time but I would not be surprised if the number of lung / respiratory diseases spiked, in of course a “non-Fukushima related” yet potentially lethal fashion in weeks to come, especially when officials or public figures are involved. After all, in the United States, “heart attack” is often a code name for drug overdose for this population, so pneumonia, bronchitis and, why not, severe asthma could become the same for radionuclide-induced cancers and acute poisoning (once in lungs, they move on into blood).

Update: Japan Times reported in April that pneumonia cases were on the rise in Tohoku, with a number of patients five to six times higher than the previous year at the same time.