"Where did you get this from?"
To be honest?
Not from deep research, but just from the known fact, that radiation increases cancer risk and that at Fukoshima was lots of radiation released.
"One of the nice things about nuclear is that you can literally Google radiation maps from various time period"
And there are different types of radiation. Some not so bad as background, or standing next to it, but very dangerous when eaten. I do not know when going in the forest and I do not want to walk around with a geiger counter. They still do not disclose how much wild boar meat has to be thrown away regulary in germany because of chernobyl.
And if the data in Japan does not show an increase, well then it is either all good (because most was washed into the sea) - or maybe not correct data. I don't know about the japanese government, but here in the east block after chernobyl, there was never a official problem in the first place. And the japanese government hopefully is better than the stalinists were, but bending the truth to save face, is a known motive there as well.
And the thing is, like I said, I am not anti nuclear. But solar panels and wind turbines simply do not have this problem ever.