In recent years, a really big suspect has become arsenic.
First of all, even a small exposure inhibits the immune system from detecting novel pathogens, allowing them to establish themselves. Then when they are detected, the immune system overreacts with the cytokine storm.
For this reason, though arsenic is quite common from water wells (USGS), the EPA prohibits it in drinking water greater than 10 ppb (parts per billion), a ridiculously small amount.
https://www.wired.com/2013/09/arsenic-nation/
However, this being said, all this shows is that arsenic can *artificially induce* a cytokine storm. It does not mean that arsenic is the only thing that can do it, or that it is even a frequent cause of cytokine storms.
That is interesting. Dont know if we were on a well system or not. Dont remember anything in the ground .
We use a Berkey water filter in my home. Have done for 15 years. The secondary filter removes metals and fluoride. Maybe there is a better option, but until I hear about it...I like my Berkey