Overview
Xie and colleagues measured arsenic (tAs) and cadmium (Cd) alongside selenium (Se) in 54 commercial selenium-enriched rice samples sourced from 14 provinces across China, finding that the premium nutritional positioning of Se-enriched rice does not preclude co-contamination with toxic elements. Arithmetic mean concentrations were 0.11 mg/kg (110 ppb) for total As and 0.08 mg/kg (80 ppb) for Cd, measured by HDXRF spectrometry. A Monte Carlo-based health risk assessment found overall risk from As and Cd intake via Se-enriched rice to be within acceptable bounds under average consumption, but highlighted that Se bioaccessibility (median 7.0 µg/kg, overall 14.6 ± 8.7%) varied substantially by region, with southern China showing the highest bioaccessible Se (29.0 µg/kg). The study is notable for combining speciation-naive total-element analysis with in vitro digestion (PBET model) for Se, without speciation of As into inorganic and organic fractions.
Key numbers
- n = 54 commercial Se-enriched rice samples, 14 provinces (northeast, northwest, southwest, south, central, and east China)
- Total As, arithmetic mean: 0.11 mg/kg (110 ppb), wet weight (assumed polished rice, dry-weight basis not specified; Shapiro-Wilk normality confirmed, p > 0.05)
- Total Cd, arithmetic mean: 0.08 mg/kg (80 ppb)
- Se total concentration: regional variation reported; highest in southern China
- Bioaccessible Se (PBET model), median: 7.0 µg/kg; highest region (northeast) mean: 20.0 ± 9.9%; lowest region (eastern) mean: 8.4 ± 4.7%
- As speciation: not performed; values are total arsenic only
- Chinese national standard for Cd in rice: 0.2 mg/kg (GB 2762-2017); Codex standard: 0.4 mg/kg
- Spatial distribution mapped using ArcGIS 10.0
Methods (brief)
HDXRF (high-definition X-ray fluorescence) spectrometry for total As and Cd in rice grain. Se bioaccessibility assessed by PBET in vitro digestion. Statistical analysis in SPSS 21.0 and Origin 2022; normal distribution confirmed for As, Cd, and Se by Shapiro-Wilk; Kruskal-Wallis H used for bioaccessible Se (non-normal). LOD/LOQ not stated in extracted text. Note: As values are total arsenic; the study does not speciate inorganic from organic arsenic, making direct comparison to iAs-specific regulatory thresholds (e.g., EU Reg. 2023/915 for rice) inappropriate without a conversion factor.
Implications
Certification: Se-enriched rice is a niche but growing product category marketed as nutritionally enhanced; the co-occurrence of tAs at 110 ppb mean and Cd at 80 ppb means that Se fortification does not create a clean-metal profile. These concentrations are below Chinese regulatory caps but at levels relevant to HMT&C threshold discussion for rice-based products.
Courses: Useful case study for explaining that nutritional fortification does not eliminate heavy metal risk; the “health halo” of selenium-enriched products needs qualification.
App: tAs 110 ppb mean and Cd 80 ppb mean for commercial selenium-enriched polished rice from China. Note: total As, not iAs; app risk scoring for iAs should apply a conservative fraction (typically 0.5–0.7 for polished white rice from Asia without speciation data).
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Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
|---|---|---|---|
| a8052bb | 2026-08-09 | major | 6 sections added; narrative text revised |