Now, I am really scared that even stuff sold in California is probably lead paint tainted turmeric.
In the same way that a lot of apples and the like will be buffed and then a soft wax coat applied so lots of apples are very shiny at the store.
if the turmeric is ground before sale i doubt there's any reason to use lead chromate.
If the turmeric is ground before sale, it's even easier to apply lead chromate and make the whole version "appear" healthier to the next processor who grinds it down and then sells the powder. If you buy it whole, then you can more easily see the color of the original root.
If the roots are wholesaled to the grinder, and the grinder doesn't know that bright means poisoned, they might prefer brighter looking roots. The ground tumeric will be poisoned.
Similarly, if the roots are poisoned and discriminating buyers aren't buying then because they're too bright, you can still grind it and sell it, and the color will blend.