If you have more info on that, I'd be interested. They're currently trying to keep it geologically stable and far away from any water that might disperse it, but then dispersion by just putting tiny tiny quantities per m³ of sea water sounds... almost too easy to be true tbh. Would be interesting to read about. (Surely they've looked into this and found that stable geology was the better solution, rather than that it's just more palatable to the public!)

And do you know, even if there's no trace today (sufficient dilution), if it also didn't have an impact on the ecosystem in the area at the time?