Radioactive Japan: Strange Case of 1,660 Bq/kg of Cesium from Ornamental Apple in Abiko City, Chiba

When I saw the tweet, I thought it was another prank. The tweet had a link to a PDF file about the high levels of radioactive cesium in one tree in the yard of a resident in Abiko City located on the west corridor of Chiba with relatively high radiation contamination. The web address of the link indicated it was from the city government, but there was no mention of the city in the document. So I went to the homepage of Abiko City, and see if I could find the same document from the links at the homepage.

Well I could. After 4 clicks, I landed on this particular page which has a link to the PDF: http://www.city.abiko.chiba.jp/index.cfm/18,101468,241,1019,html

The apple in question was brought by a city resident and tested on August 20, 2012 using the city's NaI scintillation survey meter. As the number was extraordinarily high, the city sent officials to the resident's home to collect more samples and tested them using the germanium semiconductor detector to be more precise. The result using the germanium detector was even higher.

The city says it was cautious in releasing the information, for fear that it might generate "baseless rumors". The amount of radioactive cesium in the apples, leaves and branches from the particular tree was extremely high, and couldn't be explained by comparing it to the samples taken in the same yard and in the neighborhood.

The apple tree is an ornamental apple tree, though the fruit is edible. It was planted by the resident of the house about 6 years ago when the resident moved in. The resident brought the apple to the city's testing lab, and the test was conducted on August 20, 2012.

more at the link

"The test results (radioactive cesium total):

Apple

Using the city's NaI scintillation survey meter: 1,500 Bq/kg

Using the survey meter at the Board of Education: 1,300 Bq/kg

Using the germanium semiconductor detector: 1,660 Bq/kg

Soil where the apple tree was planted

Using the survey meter at the Board of Education: 2,900 Bq/kg

Leaves and branches of the particular apple tree

City's test: over 10,000 Bq/kg "

A typical banana has .5 g of radioactive potassium. A typical banana has a rate of 31 Bq/gram due to this (see ref below). Multiplying by 1000 grams/kg this gives a corresponding average banana a measurement of 31000 Bq/kg.

so: 31 Bq/g x 1000 g/kg = 31000 Bq/kg.

31000 Bq/kg banana / 1660 Bq/kg this apple = 18.67 bananas/this apple.

So the average banana can be expected to be 18 2/3 more than this apple. Which backs up what I’ve been saying all along - you can measure anything you want throughout Japan or near any other nuclear site - but without references on what is expected to be naturally occurring no one can tell if anything is really an issue or not. By the way just caculating the .5g of radioactive potassium in the banana gives you a dosage of ~.1 microseiverts. (5.02 nSv/Bq X 31 Bq/g X .5 g = 78nSv ~ .1 uSv)

For those who are more familiar with the older terms 1 mRem = 10 uSv so .1 uSv/banana X 1 mRem/10 uSv = .01 mRem/banana)

Natural expected background exposure is 360-880 mRem/year depending on altitude and location.

Brazil nuts by the way can be as much as as 4 times higher than the bananas due to natural radon.

Ref: http://health.phys.iit.edu/extended_archive/9503/msg00074.html (gary mansfield, Lawrence Livermore National Laboratory, the University of California)

You can also go to http://en.wikipedia.org/wiki/Banana_equivalent_dose for additional information or
http://rehs.rutgers.edu/online_training/xray_train/Five.html
http://www.tenorm.com/bkgrnd.htm
http://web.princeton.edu/sites/ehs/osradtraining/backgroundradiation/background.htm#top
http://en.wikipedia.org/wiki/Background_radiation
http://www.civildefensemuseum.com/southrad/conversion.html

Your examples do not compare with Cesium contamination. It’s an apples to oranges comparison that is not relevant. If you want cold hard data relevant to Cesium contamination, check out the medical studies coming out of the Chernobyl region.
The comprehensive report published in 2007 by the Annals of the New York Academy of Sciences and written by Russian Scientists Alexey V. Yablokov, Vassily B. Nesterenko, and Alexey V. Nesterenko. is described by Wiki here: http://en.wikipedia.org/wiki/Chernobyl:_Consequences_of_the_Catastrophe_for_People_and_the_Environment

And the PDF of their report (400 plus pages) is here: http://www.strahlentelex.de/Yablokov%20Chernobyl%20book%20Index.pdf

Comparisons of nuclear wastes (Cesium, Strontium, Uranium) to very different sources of radiation like Potassium in bananas, radon or background radiation are scientifically unsound. Read the PDF listed and then ask yourself if you’ve ever heard of bananas or radon damaging the health of entire region. The public concern re nuclear contamination is not misplaced. The US has state of the art research on the effects of low level radiation which proves even small amounts are damaging to human health. To read the latest in the longitudinal studies the US has been conducting on the topic of radiation, read : Health Effects of Exposure to Low Level Radiation. It’s published by National Academies Press and can be located here: http://www.nap.edu/catalog.php?record_id=1224

According to the EPA, low energy radiation is, contrary to what one might reasonably expect, more damaging than high energy radiation. The EPA makes the point that body tissue is relatively transparent to high energy radiation (not completely but in comparison with low energy radiation) but is more severely damaged by low level radiation. (conceptually, this is like a high speed ping pong ball passing straight through the body at a high energy level or bouncing around inside the body at low energy levels - the low energy trajectories are more numerous and therefore more damaging.)
The type of particles involved in radioative decay also matter, and the percentage of each type of particle released matters when calculating damaging effects of radiation.
Then there is uptake. Cesium is taken into the muscles and unfortunately the heart is a muscle. Cesium will accumulate in the body at much higher, much more damaging levels than radon or radioactive potassium. While the EPA cautions about the damaging effects of radon, it’s concerns re cesium are far more strongly worded.
The calculations you provide, and those which nuclear lobbyists provide, do not take into consideration energy levels, particles released, effects on the body (concentrate in heart muscle?) and portray bananas and Cesium is somehow equivalent (if not favorable toward Cesium) but there is a mass of humanity living with the early death, genetic damage, and chronic diseases caused by the mismanagement of a nuclear power plant in the Ukraine (Chernobyl) and its wishful thinking that Japan will somehow have a radically different outcome among its human population - especially when you consider the Soviets tried to evacuate people from areas as contaminated as those which some Japanese communities have been told is safe to live in.

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