If something is a magnitude higher (factor 10x - 30x, as you pointed out), it is not 'comparable' in its effect to the 'original' thing.
It is quite a difference whether I drink *one* beer or 10 - 30.
The exclusion zone is not what we are talking about ... or where. The article and our discussion is about the plant side.
From a radiotoxicity standpoint, they are in fact not really distinct. You may recall that Sievert is a unit of committed dose,
You try to compare stuff that can't be compared. A cosmic ray, a high energy ion, is crossing my body. Along its path it destroys a DNA strand here and there and kills some cells completely.
Incorporating a radioactive element into your body is a bit different. Yes the 'Sievert modeling guys' try to 'compensate' the different effects to get a 'uniform' threat indicator.
Makes no sense IMHO, as all those slightly different forms of radiation have completely different effects.
Plutonium e.g. settles in the bone marrow ... the deadly dose for a human is something like 50 nano grams, perhaps 100, don't remember.
Iodine accumulates mainly in the thyroid, causing cancer there. It seems you can prevent that with high doses of Iodine intake, and Thyroid cancer seems relatively easy to treat and surviving rates are high.
Cesium accumulates in bones and sinew ... I assume in muscles as well.
So, your 10x - 30x increase of radiation versus 'normal' background level still simply measures what you can count with a geiger counter. It does not take into account what happens if you inhale some dust on a dry summer day ... perhaps working in a field with your shirt of covert with sweat when the dust accumulates on your skin.
It does not take into account what you get if you eat something that 'accumulates' the radioactive material, like a chicken or its eggs, or a fish, that have 100x higher level of radioactive Cesium than the measurement you make.
So suddenly we jump from your '10x - 30x' to the more realistic '10000x - 30000x' because a human living there eats an egg or an apple or a fish that was harvested/caught there.
Do you really think the exclusive zones exist because some idiots who have no clue overreact? In THE country that has the MOST experience with radiation victims?
You do know that according to normal regulations the whole coast north east of Fukushima beyond Tokyo, roughly 10 - 20 million people ought to be evacuated?