UV radiation is quite damaging (although part of the popular “summer tan” culture) on its own. However, we also receive higher energy photons (above UV: xray, gamma) as well as some energetic muons from the sun. You get a 4x of a daily dose of radiation if you grab a flight. Around that of an xray. All of which is mostly ignored by people.
You are correct that gamma ray radiation is by far the most damaging radiation. Beta and alpha radiation can be stopped by pieces of paper (or your skin), gamma radiation will go through your house, your car, your wife, hit a dna molecule in your hair follicle, and make that hair follicle permanently gray.
More interestingly, putting the “radioactive” seawater in perspective: tritium fizzles into some beta radiation, of 18kev energy. Assuming, magically, all this (beta radiation) energy was deposited perfectly into your DNA (nearly impossible because it is beta radiation), resulting in maximal damage, in somewhere important and not the dead layer of your skin, doing a tiny calculation we can compute this damage to be that of a photon of 0.07nm wavelength (18 kev), of similar energy used in simple xray imaging (CT imaging uses 5x higher energy). With 10 becquerels / liter, 100 liters of water surrounding you, could inflict a horrible dose of 24 (hours) * 3600 (sec / hour) * 10 x 100 x 18 kev * 1.60218e-16 (Joule / kev) / 70 (kilograms per human) = 3.55958619e-9 Sv in a day
That is a terrifying amount of 3.6 nSv. Almost close to 1/20 that of a banana you eat (I am not joking, just smiling heavily).
Fun facts: https://xkcd.com/radiation/
The fact that people talk about radioactivity in this news, and chinese being angry and the world going apeshit is… unfathomable.
dominion? Surely domino? I keep seeing people misspell words, by writing completely different words. Feels like we are getting surrounded by ChatGPT.