I'd be surprised if the final effects were poor, considering Edwards's background in CG.
It'd be underwater. One of the best possible natural mediums for shielding against radiation. You literally cannot irradiate water. You can swim in a tank of water meant for cooling rods and suffer no ill effects.You absolutely can irradiate water. And there is so very much stuff in the water that can also be irradiated.
It's better than nuclear fallout.