What is the risk to humans?
It doesn’t matter. No matter how toxic releases of radioactive wastes are, the nuclear industry and it’s insurer (the government) always specify “no immediate risk to human health.” Even if people are still suffering and dying in the Chernobyl area and regions removed from there....the official story is “no harm to human health” whenever someone asks.
How far can a toxic level spread?
Around the world eventually. Tuna caught off the coast of Fukushima can end up in your dinner table because fish swim and we import goods from around the world.
Do radioactive fish glow in the dark?
No - they look like non radioactive fish unless they had time to develop lesions in their flesh from exposure. International research vessels in the waters of Japan captured fish which looked normal but had high levels of radiation in the flesh. The food chain doesn’t help - small contaminated fish eaten by larger fish eaten by ...well....tuna and other commercial catch. Fukushima is a massive experiment on a global scale - we have never seen this amount of radiation dumped directly into the ocean - the threat of harm to wildlife and humans comes from research but never on this scale.
I was being facetious about fish glowing in the dark.
Yes, it is logical to know that people around Chernobyl, as well as Fukushima might be affected from radiation.
I do not, however, think that dangerous Fukushima radiation is going to migrate around the world via sea water.
Just checked my can of "Premium Stop & Shop Albacore Tuna." It's from Thailand, which is a fair distance from Japan. But who knows exactly where the fishing grounds of the tuna actually are? Yes, I agree -- we are all now guinea pigs.