> I assume the iodine is about water treatment and not radiation?

If you live with-in 50 km of a nuclear power plant (e.g., southern Ontario), you are entitled to free iodine pills:

* https://www.preparetobesafe.ca

* https://www.cnsc-ccsn.gc.ca/eng/resources/educational-resour...

* https://www.torontocentralhealthline.ca/displayservice.aspx?...

* https://www.durham.ca/en/news/ki-tablets-available-for-all-a...

It was a remark about nukes. Fortunately the place id go to is on a fresh water lake and we already have Water filtration setup.

I presume that radiation is why the Ukrainian brought it up.

The article did mention using it for treating water, but it's not very good at that, and it tastes awful. Reverse osmosis works much, much better and it doesn't need to be a large permanently installed system; portable gravity-fed versions readily available.