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 Canned seafood (canned tuna, canned fish)’s own as-consumed 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-consumed basis. Every analyte carries a firm ceiling. A brand meeting every value on a like-for-like basis qualifies for the mark.
| Analyte | HMTc limit | Binding basis |
|---|---|---|
| Lead (Pb) | 200 | strictest government ML (Costa Rica) |
| Inorganic arsenic (iAs) | 100 | strictest government ML (EU) |
| Total arsenic (tAs) | 1000 | strictest government ML (Singapore) |
| Mercury, total (tHg) | 500 | strictest government ML (Costa Rica) |
| Methylmercury (MeHg) | 500 | strictest government ML (Mexico) |
| Cadmium (Cd) | 50 | strictest government ML (GSO) |
| Nickel (Ni) | 2000 | government read-across (EU) |
| Total chromium (Cr) | 1000 | strictest government ML (Hong Kong) |
| Hexavalent chromium (Cr-VI) | 10 | government read-across (US-CA) |
| Tin (Sn) | 100000 | strictest government ML (Mexico) |
| Aluminium (Al) | 100000 | government 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. Mercury is limited in both forms: total mercury (tHg) and methylmercury (MeHg) are separate ceilings that must both be met, set to the species-specific tier each government assigns (predatory fish carry the higher methylmercury ceiling, lower-trophic species the lower; where the total-mercury ceiling is stricter, methylmercury is bounded by it). Total arsenic (tAs) operates as a reflex screen to inorganic-arsenic (iAs) speciation, since most arsenic in seafood is non-toxic organic arsenobetaine. Every panel analyte carries a limit of record; where no government regulates the exact product (nickel, hexavalent chromium, aluminium, and non-canned tin), the ceiling is a disclosed read-across to the nearest applicable sovereign instrument named in the derivation, never an occurrence-derived number. Tin migrates from the can, so for non-canned seafood the read-across is a packaging-migration baseline that clean product clears.
Derivation
The full derivation for Canned seafood (canned tuna, canned fish). Each row lists every government maximum level in force worldwide, converted to the as-consumed 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.
| Analyte | EU | AU/NZ | GSO | China | India | Mercosur | Costa Rica | Ecuador | Fiji | Guyana | Israel | Morocco | Mexico | Panama | Philippines | Paraguay | Singapore | Thailand | Trinidad & Tobago | Uruguay | Vietnam | Hong Kong | HMTc | Binds |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lead (Pb) | 300 | 500 | 300 | — | 300 | 300 | 200 | — | 200 | 300 | 300 | — | 1000 | 300 | 300 | 300 | 2000 | 300 | 2000 | — | 300 | 300 | 200 | Costa Rica |
| Inorganic arsenic (iAs) | 100 | — | — | 100 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 100 | 100 | EU |
| Total arsenic (tAs) | — | 2000 | — | — | — | 1000 | — | — | — | — | 1000 | — | — | — | — | 1000 | 1000 | — | — | — | — | — | 1000 | Singapore |
| Mercury, total (tHg) | 1000 | 1000 | 1200 | — | 1000 | 500 | 500 | 1000 | 500 | 500 | 500 | 1000 | — | 1000 | — | 500 | 500 | — | — | 500 | 500 | 500 | 500 | Costa Rica |
| Methylmercury (MeHg) | — | — | 1200 | — | — | — | — | — | — | — | — | — | 500 | — | 500 | — | — | 1000 | 500 | — | 500 | 500 | 500 | Mexico |
| Cadmium (Cd) | — | — | 50 | — | 300 | 50 | 50 | — | 50 | 50 | 50 | 100 | 500 | 50 | — | 50 | — | 1000 | — | — | 50 | 100 | 50 | GSO |
| Nickel (Ni) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2000² | read-across |
| Total chromium (Cr) | — | — | — | — | 12000 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1000 | 1000 | Hong Kong |
| Hexavalent chromium (Cr-VI) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 10² | read-across |
| Tin (Sn) | — | — | — | — | 200000 | — | 200000 | — | — | — | — | — | 100000 | — | — | — | — | — | — | — | — | — | 100000 | Mexico |
| Aluminium (Al) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 100000² | read-across |
All values µg/kg (ppb), as-consumed 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.
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.
2 studies in the certified-market pool measured lead in Canned seafood across 45 certified-market samples. The pooled distribution centres on a median of 51 ppb and reaches 151 ppb at the 95th percentile. Rustemli 2026, Depaiva 2017.
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 173 ppb (provisional), against a government ceiling of 200 ppb. Why lead is limited →
2 studies in the corpus measured inorganic arsenic in Canned seafood (30 samples reported across those studies): Munoz 1999, Brooke 1981.
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. Why inorganic arsenic is limited →
1 study in the certified-market pool measured total arsenic in Canned seafood across 35 certified-market samples. The pooled distribution centres on a median of 3 mg/kg and reaches 6.8 mg/kg at the 95th percentile. Rustemli 2026.
HMTc sets 1 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 7.4 mg/kg (provisional), at or above the government ceiling of 1 mg/kg, so the government maximum binds. Why total arsenic is limited →
2 studies in the certified-market pool measured total mercury in Canned seafood across 65 certified-market samples. The pooled distribution centres on a median of 279 ppb and reaches 1.2 mg/kg at the 95th percentile. Rustemli 2026, Depaiva 2017.
HMTc sets 500 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 1.5 mg/kg, at or above the government ceiling of 500 ppb, so the government maximum binds. Why total mercury is limited →
1 study in the certified-market pool measured methylmercury in Canned seafood across 30 certified-market samples. The pooled distribution centres on a median of 130 ppb and reaches 293 ppb at the 95th percentile. Depaiva 2017.
HMTc sets 500 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 500 ppb (provisional), against a government ceiling of 500 ppb. Why methylmercury is limited →
1 study in the certified-market pool measured cadmium in Canned seafood across 10 certified-market samples. The pooled distribution centres on a median of 133 ppb and reaches 193 ppb at the 95th percentile. Depaiva 2017.
HMTc sets 50 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 195 ppb, at or above the government ceiling of 50 ppb, so the government maximum binds. Why cadmium is limited →
1 study in the certified-market pool measured nickel in Canned seafood across 35 certified-market samples. The pooled distribution centres on a median of 345 ppb and reaches 786 ppb at the 95th percentile. Rustemli 2026.
HMTc sets 2 mg/kg by read-across: No government sets a nickel ML for animal seafood (EU 2024/1987 nickel covers plant foods and seaweed only). Read-across to the nearest whole-food nickel ceiling (EU 2024/1987 husked rice, 2000) that accommodates observed canned-fish nickel occurrence; clean product passes, grossly nickel-elevated product fails. Why nickel is limited →
2 studies in the certified-market pool measured tin in Canned seafood across 35 certified-market samples. The pooled distribution centres on a median of 53.5 mg/kg and reaches 107 mg/kg at the 95th percentile. Rustemli 2026, Depaiva 2017.
HMTc sets 100 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 127 mg/kg, at or above the government ceiling of 100 mg/kg, so the government maximum binds. Why tin is limited →
1 study in the certified-market pool measured aluminium in Canned seafood across 35 certified-market samples. The pooled distribution centres on a median of 16.4 mg/kg and reaches 29.1 mg/kg at the 95th percentile. Rustemli 2026.
HMTc sets 100 mg/kg by read-across: No government sets an aluminium contaminant ML for food; dietary aluminium is managed by weekly intake against the EFSA/JECFA TWI. Read-across to the nearest food aluminium instrument (China GB 2760 baked-foods aluminium, 100000) as a monitor/baseline ceiling; canned-fish aluminium occurrence (up to about 34000) sits below it, so clean product passes while gross contamination fails. Flagged monitor/baseline, not per-lot-critical. Why aluminium is limited →
Risk Flag
Where certification is demanding for this subcategory, and why. These carry a natural or process background that runs above the limit — the limit being the strictest government maximum for the product, never a percentile of market data (Method v2.0). A product is not disqualified by this — only its own tested result decides certification, and a well-sourced lot can sit well below the market.
Cadmium
Cocoa, leafy greens, sunflower and other seeds, organ meats, shellfish, seaweed, and some root vegetables concentrate cadmium from soil and seawater.
Multipliers are the ratio of the pooled occurrence median to the published limit; occurrence characterises the market only and carries no compliance weight. See the cross-category summary.
Cite this standard
Pendergrass, K. (2026). Canned seafood (canned tuna, canned fish): HMTc standard (Standard No. 10.83138/hmtc.std.6.canned-seafood). Institute of Contaminant Standards. https://doi.org/10.83138/hmtc.std.6.canned-seafood
© 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.