I don't know about Fukushima but I am sure some of the Pacific atolls used for nuclear testing are leaking. I was hoping today to catch up with someone who wrote a report on this years ago, but it appears he is away this week. Atolls are of course made of limestone derived from coral, which is porous. The underground explosion then cracks the limestone making it even more porous. Strangely enough, water then leaks through the limestone and releases radioactivity. It's a scenario that could never have been predicted
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Of course this situation is different to Fukushima but folk might be interested to know of this on-going (and generally ignored) pollution.