@JF Aus, it appears I wasted my key strokes. Just in case, I'll repeat the basics.

It is the dose, and dose rate, not the source, that increases the risk of harm. Somewhat analogous to incidental sunshine and solariums; one's body cannot distinguish that the solarium is not natural and the sunshine is, but it sure notices the massive dose and high dose rate of UV energy from the solarium. Similarly, the massive dose of radiation associated with radiotherapy destroys cancer cells. It also makes people feel ill from the large dose that misses the target and goes to surrounding healthy tissue (despite best efforts)until they have repaired. But a few extra bananas in your week or a just barely detectable level of some foreign source of radiation is not going to budge your risk profile.

Of course, if you want to listen to Arne and his ilk and be sh!tscared by all this, be my guest. Others may choose to understand the processes at play, put things in context and get on with life.

@Arjay I'll interpret your silence on the subject of the article that started all this as a concession that it is a lot of old cobblers, but you are too intellectually dishonest to concede this.

@Ben Heard,
I hear you Ben.
But dose of what?
And dose of what at what dose rate?
What might be the impact of one dose of one single micro-particle of Cesium?

Perhaps Chris Busby's "tears" were because people were no longer buying his pretend medicine? Just a thought.

@JF Aus No worries.

Dose of radiation. Radiation can occur in a few forms that penetrates and impacts on human tissue in some slightly different ways. Just measuring the raw radiation is done in units of becquerals or Gray. To understand how it might impact a human, the difference is expressed in Relative Biological Effectivness (RBE). Now, there is a unit called the Sievert that accounts for the RBE, so if you see things expressed in Sv, you know they are comparable. This is a bit like the way the multitude of different greenhouse gases are normalised and expressed in tCO2-e (tons of carbon dioxide equivalent). Not a perfect example, but not bad.

From here, an inforgraphic is truly worth 1,000 words. This brilliant inforgraphic captures both the dose and dose rate issue to give you a really good understanding. http://www.informationisbeautiful.net/visualizations/radiation-dosage-chart/ Go all the way to the bottom to see the scales at play.

Note the level 100mSv being the lowest annual dose at which any increased risk of cancer has been evident. That data was comes from the a-bomb survivors; a not inconsiderable dose in the scheme of things. But the increased risk they refer to at that level is very, very small.

Note on this chart, some of the instant dose levels that appear pretty small are, nonetheless, things like x-ray and CT scans.

So, to your question, the dose of one single micro-particle of caesium and having it stay in your body? I can't say for sure, but I can't see how that could even get a place on this chart at the low end.

What do you think?

@ Ben Heard

I think all government and radiation and other experts best think about dispersal and impact of caesium following leakage into ocean food web currents from likes of the Fukushima nuclear breakdown.
Not being able to measure a particle of caesium that may become lodged in a human body and cause cancer should be reason for great concern that should justify all relevant research possible. For example new absolutely sensitive measuring technology seems essential, both to help find a single caesium particle in food, and for human body biopsy science.
I am not a radiation expert and until today spelt caesium Cesium.
But I understand coastal currents linked to the world ocean food web and caesium in those waters should be immediately assessed and precautions taken urgently for the immediate future.
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@JF Aus, you are suggesting we go after barely detectable levels of one specific type of contamination in fish that will result in some kind of increased risk that would be calculated to be zero point lots more zeros "something".

Ok, that's one idea.

OR, maybe we close every single coal plant in the world in favour of a nuclear plant, and instantly eliminate vast quantities of a wide range of toxic environmental pollutants that are dumped on use every single day with no controversy whatsoever.

You have to measure you monsters.