Rice finding 1731

Source evidence and comparison details for the Rice profile.

Authors 2017

Rice grain (form not stated; dried and powdered); begamai rice · Nickel (Ni) · 24 rice samples (24 per type); each digest analysed in triplicate.

Selected finding and reference

13,700 µg/kg (mean ± 4,020 SD)Mean.

24 rice samples (24 per type); each digest analysed in triplicate. Basis: dry weight (oven-dried 65 °C; Table 2 does not state basis explicitly).

no non-detects reported; no LOD/LOQ reported

HMI baseline position

High · HMI dry-grain Ni reference · 1 sampling family. Mean as reported: 13700 µg/kg. HMI median 349; Q1 305; Q3 376 µg/kg. 1 family. 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.

Reference, contributing evidence and methods

Collection period

2016–2017

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

Geographic scope

Rice1 (n = 24), rice begamai

Rice variety or type within one study.

Sampling, analysis and reporting limits

0.5 g dried sample digested in HNO3 then HClO4 at 90 °C; ICP-MS (Agilent 7500 CX) at Institute of Urban Environment, CAS Xiamen.

no non-detects reported; no LOD/LOQ reported

Source inconsistency noted (does not affect this value): mean Ni of ~14 mg/kg in rice grain is one to two orders of magnitude above typical published rice Ni and is near-identical to the paper's fruit and vegetable Ni means (10–17 mg/kg), suggesting a systematic analytical or reporting problem; Table 4 rice Ni HRI (1.02e-2 adults) is also inconsistent wit

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
mean13.74 ± 4.02mg/kg x 1000

Original SD: 4.02 mg/kg.

Table 2, Cereal crops, Rice1 (n = 24) row, column Ni; p.4.

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 Ni reference · 1 sampling family. Dry-weight grain, µg/kg dry weight. Distribution of subgroup median concentration values.

Reference (µg/kg)Q1MedianQ3
Primary HMI reference305349376
Alternative weighting305349376

5 reference units; 1 sampling family. Counts describe evidence units, not independent studies or certainty.

Contributing familyReference unitsWeight
Myat Soe et al. (2023)5100%

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. This is the only compatible family for this scope in the completed rice ledger; a single-family reference cannot represent other markets. 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-Ni:e91fb60d7d27

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.