Yes there’s information all over the web. The excerpt you provide doesn’t address cummulative exposure. Here’s an excerpt from the web as well (Scientific American):
“Some evidence suggests the kind of radiation emitted by tritium—a so-called beta particle—is actually more effective at causing cancer than the high-energy radiation such as gamma rays, even though skin can block a beta particle.”
https://www.scientificamerican.com/article/is-radioactive-hydrogen-in-drinking-water-a-cancer-threat/
Sadly, as US nuke plants have tritium in the groundwater, the gov/nuke industry is defining hazard downward and in a year or two, will have “Science” to “Prove” that it’s less harmful than milk.
Fukushima’s leaking ground water has not been treated and therefore contains many harmful isotopes like Cesium 137 and Strontium 90 and that flows into the ocean daily and will continue to do so. Perhaps since they are now going to flush the tank water into the ocean, and the tanks were temporary (flimsy and leaking) to begin with, they will no longer treat any water and just let radioactive groundwater flow into the ocean without treating any of it.
I understand Fukishima and the effects of its catastrophic failure and ruptured systems, but you make it sound like every nuke plant in the world leaks water like sieve.