Lech et al. 2020 — Turmeric as a lead exposure source in the US
The first systematic survey of lead concentrations in ground turmeric sold at retail in the United States. Nearly all 127 products contained detectable lead, with mean concentrations of 1,410 ppb and a range spanning three orders of magnitude (10 to 7,590 ppb). The study establishes that lead-contaminated turmeric is not exclusively a South Asian supply-chain problem; it reaches US consumers through imported ground turmeric at retail.
Key numbers
n=127 ground turmeric products from US retail outlets.
Mean Pb: 1.41 µg/g (1,410 ppb). Median Pb: 1.12 µg/g (1,120 ppb). Range: 0.01 to 7.59 µg/g (10 to 7,590 ppb). 95th percentile: approximately 5.0 µg/g (5,000 ppb).
Regular turmeric consumption at median Pb levels could contribute 10-20% of the FDA’s reference dose for lead exposure.
Methods (brief)
Analytical: ICP-MS following sample digestion. Products purchased from various retail sources across multiple US regions.
Implications
Certification: US-retail turmeric carries meaningful Pb concentrations. Brands using turmeric as an ingredient (supplements, spice blends, beverages, functional foods) face lot-level variability spanning 3 orders of magnitude. Supplier specification and incoming-lot Pb screening are the minimum controls.
Courses: demonstrates that import controls (FDA Import Alert 99-42) do not fully prevent contaminated turmeric from reaching US retail. The 7,590 ppb maximum in a retail product is 76x the FDA action level of 100 ppb for Pb in food.
App: turmeric as an ingredient carries a Pb risk flag regardless of sourcing region, because US retail products show high variability.