Rice finding 1551
Source evidence and comparison details for the Rice profile.
Packed retail rice grain (form not stated; cleaned, dried at 40 C, milled to powder) · Lead (Pb) · Sample count unreported.
Selected finding and reference
Sample count unreported. Basis: dry weight (paper states mg kg-1 dry weight).
Non-detects not described for this analyte in rice; no values imputed by extractor.
HMI baseline position
High · HMI dry-grain Pb reference · 3 sampling families. Mean as reported: 1350 µg/kg. HMI median ≤5; Q1 ≤2.5; Q3 32 µg/kg. 3 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 is an external comparison; the finding does not set the 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 WHO GEMS/Food: Limited data.
- Without Cantoral et al. 2024: High.
- Without TatahMentan et al. 2020: Limited data.
These checks show dependence on each sampling family; they are not confidence intervals.
Collection period
2014
No year-by-year sample register is reconstructed from this summary.
Geographic scope
all rice brands
All samples in the study.
Sampling, analysis and reporting limits
Dry ashing at 500 C, HNO3/H2O2 dissolution, ICP-OES (PerkinElmer 7300 DV).
Non-detects not described for this analyte in rice; no values imputed by extractor.
Source inconsistency noted (does not affect this value): rice Pb mean of 1.35 mg/kg (1350 ug/kg) and minimum of 0.99 mg/kg are one to two orders of magnitude above typical market rice Pb and above the rice CRM certified value (NCS ZC 73008, 0.08 mg/kg) that the method recovered at 96.2%; values are reproduced exactly as printed. Range is across brand mean
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 |
|---|---|---|
| mean | Pb levels in different brands of rice samples varied from 0.99 to 2.3 mg kg-1, with a mean concentration of 1.35 mg kg-1 | mg/kg x 1000 |
Results, p. 3-4 (Pb paragraph); Figure 1; consistent with Table 3 rice Pb EWI 17.32.
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 Pb reference · 3 sampling families. Dry-weight grain, µg/kg dry weight. Distribution of subgroup median concentration values.
| Reference (µg/kg) | Q1 | Median | Q3 |
|---|---|---|---|
| Primary HMI reference | ≤2.5 | ≤5 | 32 |
| Alternative weighting | ≤2.5 | ≤5 | 32 |
7 reference units; 3 sampling families. Counts describe evidence units, not independent studies or certainty.
| Contributing family | Reference units | Weight |
|---|---|---|
| WHO GEMS/Food | 4 | 33% |
| Cantoral et al. 2024 | 1 | 33% |
| TatahMentan et al. 2020 | 2 | 33% |
Methods
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
Reference version and interpretation
Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.
hmi-pooled-reference-v2:rice-dry-Pb:6c0ebd5619fe
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.