Then you keep the seaweed for 90 days and it's not radioactive anymore? Iodine 131 has an 8 day halflife, which means it's gone <1/1024 in 90 days. It decays to stable xenon 131 which gets vented.
Which also makes the hysteria against uniodized salt also look like a qanon conspiracy theory.
I'm unaware of any conspiratorial hysteria regarding salt. I only thought that I'd mention something I had found while researching causes for thyroid cancer, which I got while living in east Asia.
Which also makes the hysteria against uniodized salt also look like a qanon conspiracy theory.