Rice finding 548
Source evidence and comparison details for the Rice profile.
Brown rice (rice grain oven-dried at 60 °C for 48 h, then de-husked) · Cadmium (Cd) · 200 paired soil/rice grain field composites (5 subsamples per paddy field).
Selected finding and reference
200 paired soil/rice grain field composites (5 subsamples per paddy field). Basis: dry weight (oven-dried 60 °C, 48 h).
not reported; minima (0.003-0.02 mg/kg) printed as measured values
HMI baseline position
High · HMI dry-grain Cd reference · 9 sampling families. Median as reported: 540 µg/kg. HMI median 71; Q1 4.7–9 (bounded); Q3 149 µg/kg. 9 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: High. The position is unchanged under this alternative. This check does not address all sampling, rounding or analytical uncertainty.
Sensitivity to source selection
- Without Myat Soe et al. (2023): High.
- Without Shi et al. (2020): High.
- Without WHO GEMS/Food: High.
- Without Huang 2023: High.
- Without Li et al. 2022: High.
- Without Qin et al. 2026: High.
- Without Signes-Pastor et al. 2016: High.
- Without TatahMentan et al. 2020: High.
- Without Xie et al. 2026: High.
These checks show dependence on each sampling family; they are not confidence intervals.
Collection period
2016
No year-by-year sample register is reconstructed from this summary.
Geographic scope
Xiangtan, Hunan, 2016 survey
Collection year within one study.
Sampling, analysis and reporting limits
Grain digested with concentrated HNO3 by microwave (CEM Mars); Cd by ICP-MS (PerkinElmer NexION 300) with In internal standard.
not reported; minima (0.003-0.02 mg/kg) printed as measured values
Shared samples and study overlap
Subgroup rows, statistics of the same subgroup and the study total share samples; they are not independent results.
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 | ranging from 0.02 to 3.61 mg/kg (mean 0.69 mg/kg, median 0.54 mg/kg) in the 2016 survey | mg/kg x 1000 |
Section 3.1 Paired soil and rice samples, paragraph 2 (page 4); Fig. 2b.
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 dry-grain Cd reference · 9 sampling families. Dry-weight grain, µg/kg dry weight. Distribution of subgroup median concentration values.
| Reference (µg/kg) | Q1 | Median | Q3 |
|---|---|---|---|
| Primary HMI reference | 4.7–9 (bounded) | 71 | 149 |
| Alternative weighting | 4.7–9 (bounded) | 71 | 149 |
65 reference units; 9 sampling families. Counts describe evidence units, not independent studies or certainty.
| Contributing family | Reference units | Weight |
|---|---|---|
| Myat Soe et al. (2023) | 5 | 11% |
| Shi et al. (2020) | 32 | 11% |
| WHO GEMS/Food | 1 | 11% |
| Huang 2023 | 3 | 11% |
| Li et al. 2022 | 5 | 11% |
| Qin et al. 2026 | 5 | 11% |
| Signes-Pastor et al. 2016 | 9 | 11% |
| TatahMentan et al. 2020 | 3 | 11% |
| Xie et al. 2026 | 2 | 11% |
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
- Myat Soe et al. (2023)
- Shi et al. (2020)
- WHO GEMS/Food
- Huang 2023
- Li et al. 2022
- Qin et al. 2026
- Signes-Pastor et al. 2016
- TatahMentan et al. 2020
- Xie et al. 2026
Reference version and interpretation
Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.
hmi-pooled-reference-v2:rice-dry-Cd:59d3645f9f4f
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.