Calling it “radioactive water” at Fukushima really does readers a disservice, because not only is it incorrect, it omits important implications of the problem.
Water is H2O, right, as we all know (I hope). So H2O is only radioactive if one of the hydrogens or the oxygen atom is a radioisotope. What we have at Fukushima is water that is polluted (or contaminated) with radioisotopes. These radioisotopes don’t go away when the contaminated water is treated, they just are moved around and/or concentrated., and they still must be dealt with. Where they go following treatment of the water (or movement of the water, as with the leaks) is the key issue to follow.
But WSJ is not alone. For example, NPR reports that
The result is that there’s now enough radioactive water there to fill something like 40 Olympic swimming pools.
Arrrrrgh! Carrying the point further, we must be concerned with the actual nature of the radioisotopes in the water: what elements are they, what types of radiation do they emit, half-lives, and so forth.