I did not read the article to the end but when I read the title it makes me think already.
The first thought that comes is about nuclear safety, the thing that the Soviet union left behind outside of Russia that everyone remembers is Chernobyl, but in a secretive regime maybe there were other issues with nuclear power or nuclear weapons storage that we do not know about, plus the dumping of nuclear reactors in the sea that the article talks about, there could be a lot of things leaking where they should not be.