“If people eat this kind of contaminated food, it will affect the health of millions and millions of people, for many, many years.” Observers say Japan’s discharging of nuclear-contaminated water into the ocean may pose long-term threats to human health and the marine environment.
Bingo. The IAEA can monitor things all they want, but a big part of the plan still involves taking TEPCO and the Japanese NRA at their word because they’re the ones that actually implement the plan.
It’s probably going to be fine, but even if it is, “I’m doing what I want, just trust me bro” isn’t how a reasonable government conducts relations with it’s neighbors. Even if they are right and even if they do already have the best plan (extremely debatable), cooperation, education, and building consensus should still be the next step, not unilaterally making decisions that piss off hundreds of millions of people without addressing their concerns.