Rice finding 47
Source evidence and comparison details for the Rice profile.
Polished rice · Total arsenic (tAs) · 26 rice samples (each analysed in triplicate).
Selected finding and reference
26 rice samples (each analysed in triplicate). Basis: dry weight (sun-dried, oven-dried 60 °C 2 days; paper refers to mg/kg dry weight).
No non-detects reported; analyte-specific LOD/LOQ only in Table S2 (not in text copy); overall LOD 0.09-35.75 µg/kg, LOQ 0.023-42 µg/kg
HMI baseline position
High · HMI dry-grain tAs reference · 8 sampling families. Mean as reported: 240 µg/kg. HMI median 186; Q1 140; Q3 210 µg/kg. 8 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 FDA rice survey (2013): High.
- Without Myat Soe et al. (2023): High.
- Without WHO GEMS/Food: High.
- Without Meharg et al. 2009: High.
- Without TatahMentan et al. 2020: High.
- Without Welna et al. 2018: High.
- Without Williams et al. 2007: High.
- Without Xie et al. 2026: High.
These checks show dependence on each sampling family; they are not confidence intervals.
Collection period
Collection date unreported
No year-by-year sample register is reconstructed from this summary.
Geographic scope
Leb Nok rice
Rice variety or type within one study.
Sampling, analysis and reporting limits
Microwave digestion (HNO3/H2O2, 160 °C) and ICP-MS (Agilent 7900); total As only.
No non-detects reported; analyte-specific LOD/LOQ only in Table S2 (not in text copy); overall LOD 0.09-35.75 µg/kg, LOQ 0.023-42 µg/kg
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 | As D 0.24 0.05 (Table 1: Element, Rice variety, Mean (mg kg-1), SD) | mg/kg x 1000 |
Original SD: 0.05 mg/kg.
Table 1 'Concentrations of heavy metals in Thai local rice', p. 31 (manuscript).
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 tAs reference · 8 sampling families. Dry-weight grain, µg/kg dry weight. Distribution of subgroup median concentration values.
| Reference (µg/kg) | Q1 | Median | Q3 |
|---|---|---|---|
| Primary HMI reference | 140 | 186 | 210 |
| Alternative weighting | 140 | 186 | 210 |
32 reference units; 8 sampling families. Counts describe evidence units, not independent studies or certainty.
| Contributing family | Reference units | Weight |
|---|---|---|
| FDA rice survey (2013) | 8 | 13% |
| Myat Soe et al. (2023) | 5 | 13% |
| WHO GEMS/Food | 2 | 13% |
| Meharg et al. 2009 | 10 | 12% |
| TatahMentan et al. 2020 | 3 | 13% |
| Welna et al. 2018 | 1 | 13% |
| Williams et al. 2007 | 2 | 13% |
| Xie et al. 2026 | 1 | 13% |
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
- FDA rice survey (2013)
- Myat Soe et al. (2023)
- WHO GEMS/Food
- Meharg et al. 2009
- TatahMentan et al. 2020
- Welna et al. 2018
- Williams et al. 2007
- 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-tAs:d4f75b6c7078
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.