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The Concentration of Potentially Toxic Elements (PTEs) in Indonesian Rice and Their Health Risk Assessment

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Summary

This 2025 Indonesian national survey measured total arsenic, cadmium, and lead in cooked rice from 30 provinces (2 sampling sites per province). The study estimated inorganic arsenic by regression from total arsenic (the regression equation y = 0.4186x + 25.212 was derived from a training dataset; R2 = 0.9923) rather than by direct speciation, which is a methodological limitation. Two provinces (Lampung and Bangka Belitung, both with mining and industrial history) produced rice exceeding the Codex 2023 inorganic arsenic (iAs) ML of 200 ug/kg. Lead contamination was notable: cooked rice lead levels were associated with IQ reductions of 2.59 and 5.27 points in toddlers and school-age children respectively, partly from cookware leaching.

Key numbers

  • Mean total arsenic in cooked rice: 106 +/- 93 ug/kg dw (range: below LOD to 609 ug/kg)
  • Mean iAs (estimated by regression): 63 +/- 11 ug/kg dw (range: below LOD to 267 ug/kg)
  • iAs as share of total arsenic (As): approximately 42-59% (mean approximately 59%; estimated, not directly speciated)
  • Provinces exceeding Codex 2023 iAs ML (200 ug/kg): Lampung 267 ug/kg; Bangka Belitung 211 ug/kg
  • Estimated daily iAs intake: 0.236-0.435 ug/kg bw/day
  • Margin of exposure (MOE) using EFSA BMDL05 of 0.06 ug/kg bw/day: greater than 10,000 (classified as “possible health risk” by EFSA criteria)
  • Cooking effect on arsenic: total As approximately -34% reduction upon cooking in water
  • Lead elevation from cooking: cooked rice lead (Pb) approximately +1,403% above raw (attributed to cookware leaching)

Methods

ICP-MS (Thermo ICAP RQ) after microwave acid digestion for total arsenic (and cadmium, lead). Inorganic arsenic estimated by regression from total arsenic using equation derived from matched subset; not measured by HPLC speciation. Cooking protocol standardised (standardised rice:water ratio). Health risk assessment using EFSA dietary exposure methodology and BMDL05 of 0.06 ug/kg bw/day.

Limitations

The iAs values are estimated by regression, not measured directly by HPLC-ICP-MS speciation. The regression approach may introduce systematic error; the two provinces identified as exceeding the Codex ML may warrant re-measurement with direct speciation. Cookware contamination of lead is a confounder for the lead risk assessment but does not affect the arsenic data.

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