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Rice — bulk grain (white, brown, wild) — HMTc Standard

Standard

The Heavy Metal Tested & Certified standard for bulk rice grain — white, brown, and wild rice — stated as sold. Rice hyperaccumulates inorganic arsenic; the subcategory adopts the strictest EU rice-form maximum (non-parboiled milled rice, 150 ppb), which holds brown and wild rice to the tighter milled-rice ceiling. Every limit is the strictest maximum level any credible government sets for the product.

How limits are set

The standard for each analyte is the strictest maximum level set by any credible government regulator — among them the European Union, Codex Alimentarius, the US FDA, Australia/New Zealand, the Gulf states (GSO), and the national authorities of every jurisdiction that regulates the product — converted into Rice — bulk grain (white, brown, wild)’s own as-sold basis. It is a lookup of sovereign law, carrying at most one disclosed basis conversion where the law is written in another basis, and an explicit read-across where no government regulates the exact product. A certified product sits at or below every applicable sovereign limit at once.

Where no government regulates the exact product for an analyte, the standard does not go blank or invent a number: the limit is read across from the nearest government value for an analogous product, so a certified product still sits at or below a real sovereign limit. The ratchet tightens these after publication as surveillance warrants.

Master Limit Table

All values in ppb (µg/kg), as-sold basis. 9 of 11 analytes carry a firm ceiling; the remaining 2 are toxic species bounded by their parent totals (species ≤ total, measured on every lot), so every analyte carries an enforceable ceiling. A brand meeting every value on a like-for-like basis qualifies for the mark.

AnalyteHMTc limitBinding basis
Lead (Pb)200strictest government ML (Paraguay)
Inorganic arsenic (iAs)150strictest government ML (EU)
Total arsenic (tAs)300strictest government ML (Paraguay)
Mercury, total (tHg)20strictest government ML (Hong Kong)
Methylmercury (MeHg)bounded≤ total tHg, measured every lot (see note)
Cadmium (Cd)100strictest government ML (AU/NZ)
Total chromium (Cr)1000strictest government ML (China)
Hexavalent chromium (Cr-VI)bounded≤ total Cr, measured every lot (see note)
Nickel (Ni)1500strictest government ML (EU)
Tin (Sn)250000government read-across (Singapore)
Aluminium (Al)100000government read-across (China)

Every claim analyte is equal at the gate. A product is certified only when every analyte is at or below 100% of its published government floor or disclosed read-across; above the limit, on any metal, it is not certified and carries no mark. Inorganic arsenic (iAs) is the arsenic species that binds on rice: rice hyperaccumulates arsenic, and every government that regulates it does so by product form (milled 150, parboiled/husked/rice-flour 250, rice products 300, rice drinks 30). Non-rice cereals do not hyperaccumulate arsenic, so iAs is not-material there and total arsenic (tAs) carries the government cereal ceiling instead. Mercury is limited as total mercury (tHg); methylmercury (MeHg), which no government regulates in grain, is bounded by the total-mercury ceiling. Hexavalent chromium (Cr-VI) is controlled by reflex speciation on total chromium, not an invented number. Tin (Sn) is material only for canned product, which routes to the canned-goods category. Aluminium (Al) has no government grain maximum in any jurisdiction.

Derivation

The full derivation for Rice — bulk grain (white, brown, wild). Each row lists every government maximum level in force worldwide, converted to the as-sold basis; the HMTc limit is the strictest of them, and the last column names which sovereign law binds. A blank cell means that government sets no limit for this analyte in this product.

AnalyteEUAU/NZGSOChinaIndiaMercosurIsraelPhilippinesParaguaySingaporeThailandVietnamHong KongCOHMTcBinds
Lead (Pb)—————200——200—————200Paraguay
Inorganic arsenic (iAs)150—200———200200—200200—200—150EU
Total arsenic (tAs)—————3001000—300———500—300Paraguay
Mercury, total (tHg)——————30—————20—20Hong Kong
Methylmercury (MeHg)——————————————bounded&sup5;species ≤ tHg
Cadmium (Cd)150100400—400400200400400—400400100200100AU/NZ
Total chromium (Cr)———1000——————————1000China
Hexavalent chromium (Cr-VI)——————————————bounded&sup5;species ≤ Cr
Nickel (Ni)1500—————————————1500EU
Tin (Sn)——————————————250000²read-across
Aluminium (Al)——————————————100000²read-across

All values µg/kg (ppb), as-sold basis. ² no government regulates this analyte for this exact product form: the value is a disclosed read-across from the nearest applicable government maximum, and the derivation names the instrument it comes from. It is never taken from occurrence data. After publication the standards ratchet may tighten it, using certified-lot results only. ³ not material in this matrix: measured but with no standalone number, controlled by packaging control or by the total-metal screen, not an invented value. &sup5; a toxic species governed by and bounded by its parent total (for example inorganic arsenic ≤ total arsenic): the species can never exceed the total, so the total ceiling is the species ceiling. The total metal is measured on every lot and the species is established at baseline; no separate species ceiling is published. On ongoing lots the species is speciated whenever the total exceeds its limit.

Occurrence and derivation rationale

For each analyte on the panel: what the peer-reviewed and survey literature measured in this category, cited one way to the Heavy Metal Index, and the Method v2.0 reasoning behind the certification limit — including, where no government sets a number, why the program sets one anyway. Occurrence figures are literature findings; the derivation is the certifier's.

3 studies in the certified-market pool measured lead in Rice across 188 certified-market samples. The pooled distribution centres on a median of 10 ppb and reaches 84 ppb at the 95th percentile. Myatsoe 2023, Alrashdi 2024, Yan 2025.

3 studies · 188 samples · median 10 ppb · P95 84 ppb

HMTc sets 200 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 124 ppb, against a government ceiling of 200 ppb. Why lead is limited →

Inorganic arsenic

5 studies in the certified-market pool measured inorganic arsenic in Rice across 307 certified-market samples. The pooled distribution centres on a median of 27 ppb and reaches 111 ppb at the 95th percentile. Noh 2023, Alrashdi 2024, Yan 2025, Signes-Pastor 2016, Cr-Fsasc 2014.

5 studies · 307 samples · median 27 ppb · P95 111 ppb

HMTc sets 150 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 134 ppb, against a government ceiling of 150 ppb. Why inorganic arsenic is limited →

Total arsenic

3 studies in the certified-market pool measured total arsenic in Rice across 187 certified-market samples. The pooled distribution centres on a median of 95 ppb and reaches 395 ppb at the 95th percentile. Myatsoe 2023, Alrashdi 2024, Signes-Pastor 2016.

3 studies · 187 samples · median 95 ppb · P95 395 ppb

HMTc sets 300 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 471 ppb (provisional), at or above the government ceiling of 300 ppb, so the government maximum binds. Why total arsenic is limited →

Total mercury

2 studies in the certified-market pool measured total mercury in Rice across 55 certified-market samples. The pooled distribution centres on a median of 261 ppb and reaches 1.8 mg/kg at the 95th percentile. Enamorado-Montes 2021, Yan 2025.

2 studies · 55 samples · median 261 ppb · P95 1.8 mg/kg

HMTc sets 20 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 2.3 mg/kg (provisional), at or above the government ceiling of 20 ppb, so the government maximum binds. Why total mercury is limited →

8 studies in the certified-market pool measured cadmium in Rice across 1176 certified-market samples. The pooled distribution centres on a median of 7.4 ppb and reaches 213 ppb at the 95th percentile. Yan 2025, Wu 2024, Hbbf 2025, Myatsoe 2023, Alrashdi 2024, Vatanpour 2020, Liu 2022, Shi 2020.

8 studies · 1176 samples · median 7.4 ppb · P95 213 ppb

HMTc sets 100 ppb (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 297 ppb, at or above the government ceiling of 100 ppb, so the government maximum binds. Why cadmium is limited →

1 study in the certified-market pool measured nickel in Rice across 120 certified-market samples. The pooled distribution centres on a median of 287 ppb and reaches 1.2 mg/kg at the 95th percentile. Myatsoe 2023.

1 study · 120 samples · median 287 ppb · P95 1.2 mg/kg

HMTc sets 1.5 mg/kg (regulatory-alignment): the strictest applicable government maximum level for this product form, adopted under Method v2.0 as the default certification standard. The certified-market pool's P97 is 1.3 mg/kg, against a government ceiling of 1.5 mg/kg. Why nickel is limited →

Risk Flag

On the published occurrence literature to date, Rice — bulk grain (white, brown, wild) shows no systematic gap between typical market levels and the limit — the limit being the strictest government maximum for the product (Method v2.0). Certification is decided on a product’s own tested result, not on a distribution; an individual lot or supplier can still exceed a limit.

See the cross-category summary of the ingredients that most often struggle.

Cite this standard

Pendergrass, K. (2026). Rice — bulk grain (white, brown, wild): HMTc standard (Standard No. 10.83138/hmtc.std.3.rice-bulk-grain). Institute of Contaminant Standards. https://doi.org/10.83138/hmtc.std.3.rice-bulk-grain

© 2026 Institute of Contaminant Standards / Heavy Metal Certified. All rights reserved.

The literature baseline for every analyte is maintained independently at the Heavy Metal Index. This certification standard applies those findings; the two are kept editorially separate by design.