Reports like this that report no context, as if "radioactive" is an absolute horror, are probably intended to frighten you.

As an engineer, who has performed some nuclear engineering, here is a good reference:

"Tritium (H-3) is a weakly radioactive isotope of the element hydrogen that occurs both naturally and during the operation of nuclear power plants. Tritium has a half-life of 12.3 years and emits a weak beta particle. The most common form of tritium is in water, since tritium and normal hydrogen react with oxygen in the same way to form water. Tritium replaces one of the stable hydrogens in the water molecule, H2O, and creates tritiated water, which is colorless and odorless.

Tritium can be found in self-luminescent devices, such as exit signs in buildings, aircraft dials, gauges, luminous paints, and wristwatches. It is also used in life science research and in studies investigating the safety of potential new drugs.

What is Strontium-90?

Strontium-90 (Sr-90) is a radioactive isotope that is produced in nuclear fission, the splitting of an atom's center that releases energy. Sr-90 has a half-life of about 29 years and emits a beta particle as it decays.

Sr-90 is used as a radioactive tracer in medical and agricultural studies. The heat generated as Sr-90 radioactively decays can be converted to electricity for long-lived, light-weight power supplies. Some examples are navigational beacons, weather stations, and space vehicles.

Where do Tritium and Strontium-90 come from?

Tritium is produced naturally in the upper atmosphere when cosmic rays strike air molecules. It is also produced during nuclear weapons explosions, and commercially in nuclear reactors producing electricity.

Sr-90 comes from three sources:

Approximately 99 percent of the Sr-90 in the environment comes from weapons testing fallout. Sr-90 takes about 29 years to lose half of its radioactivity. The fallout-based Sr-90 still remains in the environment at nominal levels because Sr-90 takes about 29 years to lose half of its radioactivity. Most of the remaining one percent of Sr-90 in the environment came from the Chernobyl accident. At individual U.S. nuclear power plants, the amount of Sr-90 released is so low that it is usually at or below the minimum detectable activity of sensitive detection equipment.

How can Tritium and Strontium-90 affect me?

Exposure to very small amounts of ionizing radiation is thought to minimally increase the risk of developing cancer, and the risk increases as exposure increases.

Tritium is one of the least dangerous radionuclides because it emits very weak radiation and leaves the body relatively quick. Since tritium is almost always found as water, if ingested, it goes directly into soft tissues and organs. The dose to these tissues are generally uniform and dependent on the tissues' water content." - From the Nuclear Regulatory Commisson website.

What an intelligent person will get from this is:
A. Tritiated water that has already been stored for decades is practically non-radioactive. And it releases weak beta particles that are stopped by almost anything, including a few feet of water. I would not avoid swimming on a the same beach where tritiated water was pumped to sea.
B. Tritium is so common that it is already everywhere, and any amount that goes to the sea will be an unmeasureable increase compared to the normal exposure.
C. In the 50s, we learned a lot about radiation exposure, and one significant fact that emerged is that humans tolerate radiation very well up to certain levels, which are generally below normal cosmic gamma rays, beta particles from all sources, and all other background radiation including microwaves - all of which are a magnitude greater than what might happen if all the "hot" water on the planet were dumped into the sea. Cockroaches can tolerate living in a nuclear containment dome, as an example of living tissue that thrives in such an environment.
D. Some geneticists theorize that the speed of evolution on Earth was probably accelerated by the radiation levels that at times were much higher than today, and may have even been necessary for humans to have evolved by now.
E. And finally, absolutists who report stuff out of context, are morons.