Here is a lab-test of different Iodine "tinctures", but also sea veggies and superfood-grasses, tested for heavy metals.
I am a little surprised that the "superfoods" was so high in mercury, same average as sea vegetables.
The Iodine from JCrows have zero lead, cadmium,mercury; so it is a good recommendation of brand.
-while there should be a warning on a couple of the others
(like Lugols from rising sun; it is the only one of the Iodine tinctures containing mercury, also driving up the average of arsenic considerably)
If you look closer into the tests, you will see that the sea veggies are relatively clean from some sources / parts of the world; while nothing one would like to consume from other sources.
Here is a summary, average contents;
Superfood; 0,136 ppm
Sea vegs; 0,196 ppm
Iodine tinctures; 0,013 ppm
Superfood; 0,092 ppm
Sea vegs; 0,761 ppm
Iodine tinctures; 0,007 ppm (but only TWO of them had it)
Superfood; 0,007 ppm
Sea vegs; 0,007 ppm
Iodine tinctures; 0,009 ppm (but only ONE had it)