If you'll read the "linked" link, you'll see a link between tritium and Down's syndrome. Of course, this could not be "proved" but they did warrant further study (which of course wasn't done).
More government FUD.
Maybe read the conclusion of the "linked" paper, which doesn't support your assertion #howtoreadsciencepapers.
"The birth prevalence of Down Syndrome was elevated in both Pickering and Ajax, however
interpretation of this elevated risk must be very cautious. There was no consistent pattern
between tritium release levels and Down Syndrome birth prevalence, chance could not be ruled
out for the associations between Down Syndrome and tritium releases or ground monitored
concentrations, the association was detected in an analysis where multiple testing was done
which may readily turn up significant associations by chance, maternal residence at birth for
Down Syndrome mothers in Pickering and Ajax needs to be verified, and we have no
information about place of residence early in pregnancy"
It even goes on from there, but why should I bother quoting it when the whole paper is available to read?