Putting Fukushima in context

Tim Worstall at Forbes quotes a headline on the Fukushima power plant:

Tepco admitted on Friday that a cumulative 20 trillion to 40 trillion becquerels of radioactive tritium may have leaked into the sea since the disaster.

He says:

Most of us haven’t a clue what that means of course. We don’t instinctively understand what a becquerel is in the same way that we do pound, pint or gallons, and certainly trillions of anything sounds hideous. But don’t forget that trillions of picogrammes of dihydrogen monoxide is also the major ingredient in a glass of beer. So what we really want to know is whether 20 trillion becquerels of radiation is actually an important number. 

Yes. I have no idea if that is situation normal or a Chernobyl.

To which the answer is no, it isn’t. This is actually around and about (perhaps a little over) the amount of radiation the plant was allowed to dump into the environment before the disaster. 

And he does a comparison:

That comparison being that the radiation leakage from Fukushima appears to be about the same as that from 76 million bananas. Which is a lot of bananas I agree, but again we can put that into some sort of perspective. …

We can do this slightly differently and say that the 1.45 trillion bananas consumed each year have those 15 Bq giving us around 22 trillion Bq each year. The Fukushima leak is 20 trillion Bq over two years: thus our two calculations agree. The current leak is just under half that exposure that we all get from the global consumption of bananas.

Except even that’s overstating it. For the banana consumption does indeed get into our bodies: the Fukushima leak is getting into the Pacific Ocean where it’s obviously far less dangerous. And don’t forget that all that radiation in the bananas ends up in the oceans as well, given that we do in fact urinate it out and no, it’s not something that the sewage treatment plants particularly keep out of the rivers.

Invaluable context.