Rice finding 1455

Source evidence and comparison details for the Rice profile.

Lockwood et al. 2023

Unpolished rice (husk removed during preparation; brown/red rice) · Lead (Pb) · 1 rice samples (seven varieties; four varieties as unpolished/polished pairs).

Selected finding and reference

6 µg/kg (individual sample ± 2 SD)Individual sample.

1 rice samples (seven varieties; four varieties as unpolished/polished pairs). Basis: unspecified.

authors state all samples were above the limits of detection

HMI baseline position

Low · HMI uncooked-grain Pb reference · 10 sampling families. Individual sample as reported: 6 µg/kg. HMI median 25; Q1 10–15.5 (bounded); Q3 54.5–64.5 (bounded) µg/kg. 10 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

These checks show dependence on each sampling family; they are not confidence intervals.

Reference, contributing evidence and methods

Collection period

Collection date unreported

No year-by-year sample register is reconstructed from this summary.

Geographic scope

Siyapathal

Rice variety or type within one study.

Sampling, analysis and reporting limits

10-20 grains ground, HNO3/HCl overnight digest, solution ICP-MS (Agilent 7700s) with Rh internal standard, 8-point calibration 0.6-600 µg/kg; LA-ICP-MS imaging (unquantified).

authors state all samples were above the limits of detection

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 statisticOriginal resultDisplayed unit conversion
sample_value6 ± 2none

Original SD: 2 μg kg−1.

Table 2, row 'Siyapathal', column Pb; p.2895.

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 Pb reference · 10 sampling families. Uncooked grain as analysed (native or unstated moisture), µg/kg. Distribution of subgroup median concentration values.

Reference (µg/kg)Q1MedianQ3
Primary HMI reference10–15.5 (bounded)2554.5–64.5 (bounded)
Alternative weighting10–15.5 (bounded)2554.5–64.5 (bounded)

82 reference units; 10 sampling families. Counts describe evidence units, not independent studies or certainty.

Contributing familyReference unitsWeight
Myat Soe et al. (2023)510%
Alrashdi et al. (2024)610%
WHO GEMS/Food4110%
Mari et al. 2016310%
Authors 2016310%
Bazie et al. 2022510%
Gama et al. 2025110%
Ibrahim et al. 2024110%
Lockwood et al. 20231110%
Yan et al. (2025)610%

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

Reference version and interpretation

Frozen evidence selection: 2026-10-22. Method: hmi-pooled-reference-v2.

hmi-pooled-reference-v2:rice-native-Pb:4a9266cf68b5

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.