Rice finding 840
Source evidence and comparison details for the Rice profile.
Rice; grain form not separated · Cadmium (Cd) · 6632 rice samples.
Selected finding and reference
Basis: Rice grain; moisture basis unspecified. Source uses LOD/2 substitution. With most results censored for these analytes, reported medians are not medians of detected values.
HMI baseline position
Low · HMI uncooked-grain Cd reference · 13 sampling families. Median as reported (bounded): ≤4 µg/kg. HMI median 22–28.5 (bounded); Q1 12; Q3 73 µg/kg. 13 families. Not a safety grade.
Low is below Q1; Moderate includes Q1 through Q3; High is above Q3. Reporting bounds must give the same category throughout.
This finding’s sampling family contributes to the fixed reference.
Sensitivity to weighting
Equal subgroup weight within each family: Low. The position is unchanged under this alternative. This check does not address all sampling, rounding or analytical uncertainty.
Sensitivity to source selection
- Without Alrashdi et al. (2024): Low.
- Without WHO GEMS/Food: Low.
- Without Mari et al. 2016: Low.
- Without Authors 2016: Low.
- Without Bazie et al. 2022: Low.
- Without Cantoral et al. 2024: Low.
- Without Ibrahim et al. 2024: Low.
- Without Li et al. 2024: Low.
- Without Limmer et al. 2026: Low.
- Without Liu et al. 2022: Low.
- Without Lockwood et al. 2023: Low.
- Without Qin et al. 2026: Low.
- Without Yan et al. (2025): Low.
These checks show dependence on each sampling family; they are not confidence intervals.
Collection period
2020–2022
No year-by-year sample register is reconstructed from this summary.
Geographic scope
China · Henan
Market samples labelled Henan-grown.
Sampling, analysis and reporting limits
Microwave digestion and ICP-MS; blanks, parallel and recovery controls.
Source uses LOD/2 substitution. With most results censored for these analytes, reported medians are not medians of detected values.
Source-reported summaries retained. Table 3 contains inconsistencies, so no subgroup comparisons are used. Arsenic identity is held because the iAs wording is not supported by a documented separation in the visible method.
Shared samples and study overlap
All analytes use the same survey samples; subgroup totals must not be added.
Each table row describes a food/analyte result. Repeated rows do not add independent samples or datasets. No cross-study trend is calculated in this comparison mode.
Reported values, conversion and source locator
| Source statistic | Original result | Displayed unit conversion |
|---|---|---|
| median | 0.002 mg/kg (median) | Unit conversion only: mg/kg × 1000 = µg/kg; no moisture or cooking conversion |
Sections 2.1–2.2, statistical analysis; Table 1.
No moisture, cooking-yield or species conversion is applied to the original finding above. Any basis conversion used for its HMI comparison is stated separately with the numerical target.
Open the primary publication · HMI source record
Reference and scope
HMI uncooked-grain Cd reference · 13 sampling families. Uncooked grain as analysed (native or unstated moisture), µg/kg. Distribution of subgroup median concentration values.
| Reference (µg/kg) | Q1 | Median | Q3 |
|---|---|---|---|
| Primary HMI reference | 12 | 22–28.5 (bounded) | 73 |
| Alternative weighting | 12 | 22–28.5 (bounded) | 73 |
129 reference units; 13 sampling families. Counts describe evidence units, not independent studies or certainty.
| Contributing family | Reference units | Weight |
|---|---|---|
| Alrashdi et al. (2024) | 6 | 8% |
| WHO GEMS/Food | 42 | 8% |
| Mari et al. 2016 | 3 | 8% |
| Authors 2016 | 3 | 8% |
| Bazie et al. 2022 | 5 | 8% |
| Cantoral et al. 2024 | 1 | 8% |
| Ibrahim et al. 2024 | 1 | 8% |
| Li et al. 2024 | 3 | 8% |
| Limmer et al. 2026 | 1 | 8% |
| Liu et al. 2022 | 2 | 8% |
| Lockwood et al. 2023 | 11 | 8% |
| Qin et al. 2026 | 44 | 8% |
| Yan et al. (2025) | 7 | 8% |
Methods
HMI calculates a pooled distribution of subgroup medians across the admitted sampling families. HMI pools subgroup medians from every compatible rice sampling family in the evidence ledger for this analyte, material and basis: published subgroup medians, medians HMI calculates from printed per-sample values and WHO GEMS/Food region-by-year medians (random sampling only). Each family has equal total weight; subgroups have equal weight within a family. Non-detects stay as zero-to-limit intervals, so quartiles carry lower and upper bounds. Means, ranges and maxima never enter as observations. Dry-weight, native-moisture and cooked results are kept in separate references; no moisture conversion is assumed.
Inverse weighted empirical CDF; midpoint at exact cumulative-weight boundaries. At least four reference units and a definitely positive Q1–Q3 spread are required. This is a display eligibility rule, not statistical validation.
Limitations
An evidence-library reference, not a probability sample of the world rice market. Sampling families differ in frame (retail, farm, contaminated sites, monitoring) and period; GEMS/Food regions are reporting regions, not growing origins. Many submissions are non-detects with differing limits, which widens the bounds. A position is descriptive concentration, not a safety or compliance judgment.
Admitted source families
- Alrashdi et al. (2024)
- WHO GEMS/Food
- Mari et al. 2016
- Authors 2016
- Bazie et al. 2022
- Cantoral et al. 2024
- Ibrahim et al. 2024
- Li et al. 2024
- Limmer et al. 2026
- Liu et al. 2022
- Lockwood et al. 2023
- Qin et al. 2026
- Yan et al. (2025)
Reference version and interpretation
Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.
hmi-pooled-reference-v2:rice-native-Cd:284df7d0ac5f
The reference is computed by HMI from admitted evidence, not copied from a study baseline. It describes the evidence currently in this scope; it is not a worldwide or current-lot benchmark. Source, year and region filters do not change it. Different HMI scopes are not one common ranking.