No. Chemicals operate at the level of atoms and molecules. Nuclear radiation operates at the subatomic level and moves through matter into other matter.
You can hold a rock made of heavy metal in your hand which would kill you if ingested. If the rock were a gamma particle emitter, however, those subatomic particles will leave the rock and pass into your body, then through your body and out into the world beyond.
This poorly understood fact is what makes nuclear materials so dangerous. They simply cannot be compared to other "poisons" such as are used in solar plants or PC chips.
And the radiation that enters the water does nothing terrible there. If it is a alpha particle, it will scatter a few times, grab an electron and become a harmless helium atom. An electron from beta decay will be harmless after a few collisions. A positron from beta decay will annihilate rather quickly, producing to gamma photons. And those are absorbed in water after a few meters. Neutrons scatter down to thermal energies and decay after a few minutes. The water is not dangerous afterwards and there is no remaining radiation that needs to be filtered out. (For water that is quite different to e.g. steel that itself becomes activated and radioactive after sufficient radiation exposure.)
The specific radioactive pollutant I'm speaking of is tritium which has been found in discharge water from 45 of 65 tested US nuclear sites.[0] Tritum's half-life is more than 12 years, not a few minutes. [ibid]
Several studies have found a connection between ingestion of tritium-contamined water and health effects, including DNA damage that leads to increased infant mortality. [1][2]
Tritium isn't really a "separate chemical" but rather an isotope of hydrogen. Since water molecules are made of hydrogen and oxygen bound together, there is no simple way to remove the radioactive hydrogen by itself. The current best methods, from what I'm seeing online, involve separating the hydrogen and oxygen atoms into gasses and then processing out the tritiated hydrogen molecules. Apparently, it's expensive and only about 85% effective.
