Researchers at Stanford University have been trying to figure out why up to half the residents in rural Bangladesh have dangerously high levels of lead in their blood. For five years, they have analyzed soil samples and ruled out theories such as bad plumbing or naturally occurring sources in the water or soil. Once they began to look at food, they found the source. Turmeric producers are adding lead chromate to make the spice a more vivid yellow color. Researchers found lead levels 500 times the national limit.
Turmeric wholesalers reported that the practice of adding yellow pigments to dried turmeric root during polishing began more than 30 years ago and continues today, primarily driven by consumer preferences for colorful yellow curries. Farmers stated that merchants are able to sell otherwise poor-quality roots and increase their profits by asking polishers to adulterate with yellow pigments. Adulterating turmeric with lead chromate poses significant risks to human health and development. The results from this study indicate that PbCrO4 is being added to turmeric by polishers, who are unaware of its neurotoxic effects, in order to satisfy wholesalers who are driven by consumer demand for yellow roots.https://www.sciencedirect.com/science/article/pii/S0013935119305195?via%3Dihub#bib10
I reviewed several popular brands of bulk turmeric on Amazon. Many of them actually include a warning that the product contains lead and many of the product questions ask about lead. It seems to be an open secret. I don’t know why it took Stanford 5 years to find the source.
In Florida, I find fresh turmeric root at the local Publix grocery. It’s good in rice dishes. I’ll stick to using fresh turmeric to avoid the lead worries.