Somehow OPG has managed to accidentally dump about 300 000 litres of tritiated water into the lake.
Obviously, the fact that such an accident has occurred bothers me, but probably not for the same reasons it bothers Sierra Club or Greenpeace. In all likelihood there is probably a greater threat posed by the hydrazine than the tritium.
As much as I don't think current tritium levels are a threat (as I've outlined before, the current levels are well below Europe's advisory limits and mostly below California's absolute limits), the fact that OPG would make such a mistake and would be unable to say even how much tritium was released is unnerving. Of course, from the description of the water it sounds like it would not have been expected to have any significant quantities of tritium in it at all.