“When fallout from the Fukushima nuclear disaster began appearing last Spring in U.S. air, rainwater, drinking water, and milk, many U.S. media outlets ignored the story.”
It seems that the latest trend is scientific thinking on this subject is that there is no such thing as a 'safe dose', because it all depends on how much you have already had and for how long you are being exposed to it now, including from food and drink (you can accumulate ti from different soucres), not to mention some people are more susceptible than others.
When Chernobyl happened, I was living in South East France. Some of the radioactive stuff was heading into Western Europe. The chief scientist publicly said on TV, nothing to worry about for France, it will stop at the Alps. Of course it didn't. Then the dosage rate is so low that in any case, its not worth bothering about. So now children of that time from that area, who are now adult, have a noticeable increase above the average in things like thyroid cancer and leukaemia. Yet there are precautions that could have been taken that would have minimised that.
Its very clear that the Japanese government totally failed to take adequate precautions for its citizens in the Fukushima area. It ended up by increasing the evacuation zone in steps. It terminated at 30km radius, when the US were advising, rightly so, an 80 km radius. Not only is some radiation still being emitted from Fukushima, but they are burning the radioactive debris in most place on the coast that got the Tsunami damage, which releases stuff back into the atmosphere.
They have not cleared all the top 10cm of soil for at least a 40 km radius, so children are now playing on contaminated ground, animals grazing on it, and so on. They have not stopped contaminated water leaking into the Pacific and yet still allow fishing in it, even near Fukushima itself. They have even approved plans to dump about 1,000 tons of contaminated water a day, because they have no other means of handling it. That is going to go on for as long as it takes to decommission the site, currently estimated as at least 30 years, assuming it can be, which is far from given for the N° 1 reactor, as it is so 'hot', they can only use robots in that building.
Of course, they are making measurements that marketed food is within the 'safe' criteria. Is there actually such a thing as a 'safe' criteria if your staple food is fish and you will eat it for years?? There are even reports that hospitals have been told not to treat problems caused by radiation so that the official figures are kept very low and that citizens are not allowed to buy dosimeters and other detectors so they know what situation they are in. In the future there will be an extremely heavy toll on their citizens health for those errors, but it would seem as they will not be in office, or even alive, when most of that starts to emerge then ..... In sum, there are valuable lessons to be learnt on how best to proceed if the worst happens in your country. I hope you are insisting that they be applied.