Firstly, you don't know what you're talking about. The small amount of material released from Fukushima was just that - small. Additionally, when that is diluted amongst the world's biggest ocean, it becomes negligible.
The current evidence of the Fukushima fallout in albacore tuna is that they
have elevated levels of 134Cs and 137Cs (the two Caesium isotopes released), yet this delivers between 3.7 to 4.0 nSv, which is 0.2% of the radiation level of the background occuring 210Po radiation in the fish.
4.0 nSv is also around 1/20th of what you would ingest from a banana (40K, naturally occuring radioactive Potassium).
Careful guys, the world's gonna collapse because there's radioactive bananas!!
Secondly, just because 90S decays to 90Yt with a t1/2 of 28.8 years, doesn't mean half of it instantly decays after 28.8 years and causes cancer you fucking dildo. Cancer rates [from exposure] would be highest shortly after the disaster, falling away as time progresses.
Some pretty fuckin' wrong science. If your relative economical knowledge is just as bad, I'll do they exact damn opposite of what you say.