I talked about how water released are usually modeled and risk assessments done in another comment abour the pending release a few weeks ago but I can’t find it.
While I can’t speak for all regulatory bodies, and you could be a shitass and release toxic crap without doing a risk assesmsent, it’s very unlikely that this is the case here, particularly because it’s TREATED water that’s being released. That means they have a treatment system (there’s a fucking rabbit hole and half…) which they are using to treat the water to some acceptable criteria/standard. This mean some sort of modeling and risk calculation has been done otherwise they would have just gone ‘yolo pump the water into the ocean’.