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Heavy Metal Contamination in Commercial Turmeric: A Public Health Perspective

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Overview

Shah, Thapa, and Bhattarai measured lead and total chromium in seven commercial turmeric samples collected from local markets and supermarkets in Itahari and Biratnagar, Nepal. The source is direct turmeric occurrence evidence and is especially relevant to adulteration risk because the authors frame lead chromate as the likely concern.

Key numbers

  • Seven turmeric samples were analyzed: raw dried turmeric, unpacked turmeric powder, three Nepal-branded packaged powders, and two international branded powders.
  • Lead concentrations were 0.50 +/- 0.06 ppm in sample A, 0.24 +/- 0.01 ppm in sample B, 0.45 +/- 0.08 ppm in sample C, less than 0.01 ppm in sample D, 0.37 +/- 0.02 ppm in sample E, less than 0.01 ppm in sample F, and 0.41 +/- 0.03 ppm in sample G.
  • Total chromium concentrations were 3.31 +/- 0.06 ppm in sample A, 2.21 +/- 0.02 ppm in sample B, 1.48 +/- 0.05 ppm in sample C, 2.05 +/- 0.01 ppm in sample D, 2.44 +/- 0.02 ppm in sample E, 2.62 +/- 0.01 ppm in sample F, and 2.62 +/- 0.04 ppm in sample G.
  • Five of seven samples exceeded the authors’ cited WHO lead limit of 0.1 ppm: A, B, C, E, and G.
  • All seven samples were below the authors’ cited 6 ppm chromium limit.
  • The method limit of detection for both lead and chromium was 0.01 ppm.

Methods (brief)

Samples were dried, prepared by aqua regia acid digestion, and analyzed by atomic absorption spectroscopy. The authors used standard solutions at 1, 3, and 5 ppm for calibration; reported calibration correlation coefficients were 0.998 for lead (Pb) and 0.997 for chromium (Cr). The study reports total chromium and does not distinguish Cr(III) from Cr(VI).

Implications

Certification: This source reinforces turmeric as a high-adulteration-risk spice row for lead and total chromium. Values are finished turmeric powder concentrations in ppm, equivalent to mg/kg and micrograms per gram.

Courses: The paper is useful for teaching the distinction between total chromium occurrence and Cr(VI) hazard claims. It discusses lead chromate adulteration, but the measurements are Pb and total Cr only.

App: Route as turmeric-specific evidence with a Nepal-market flag. It supports a user-facing caution for turmeric powder where supply-chain controls and lot testing are weak.

Update history

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