I posted this above. ConsumerLab does this testing on all sorts of products and foods. They are a non-profit. The annual fee you pay supports the research and testing directly.

They tested many brands of both spice and supplement for lead, arsenic, cadmium, and mercury, and published the amounts they found in each brand:

https://www.consumerlab.com/reviews/turmeric-curcumin-supple...

Of great importance lately was their discovery of benzene in many common sunscreens which forced many product recalls. I used their findings to change brands for my entire family.