The radiation can't be detected even a couple of kilometers away from the discharge. China is >1000km away, so there's 6+ orders of magnitude more dilution by

The radiation can't be detected even a couple of kilometers away from the discharge. China is >1000km away, so there's 6+ orders of magnitude more dilution by then. If I pee in the lake you're swimming in, that's kind of gross... but it ends up being an incomprehensibly tiny fraction of the contaminants and gross stuff you're swimming in.