Heavy metals in Canned seafood (with tin flag)

Overview

Step 0 scope-locked row for HMTc Taxonomy v2.0 Category 6 (Seafood), Row 6. The row scope is locked (variant_type: whole_row_platform, platform_metals Sn). Lock authority: docs/governance/category-6-step0-lock.md.

This row carries the tin flag for tin (Sn) migration from the can, and inherits the fish-row mercury concern for its contents. Speciation (MeHg vs tHg) is non-substitutable.

Literature scope

Routable destination for source pages declaring products: [canned-seafood] and the fan-out target for broad canned-fish declarations. Reported measurements from source notes are below. Sections that are still empty have not been synthesized into a population estimate. No certification limit is stated here. HMTc thresholds for this row are developed under the certification program at heavymetalcertified.com.

Evidence summary

Evidence summary

The table below summarizes what the peer-reviewed and government literature cited on this page reports for heavy-metal concentrations in Canned seafood (with tin flag). Values are pulled directly from cited sources without re-aggregation. This page publishes literature evidence only, not certification thresholds.

Methodology rules for speciation, basis preservation, non-detect handling, and source pooling are stated in the Methodology section above and apply to every row below.

Direct answer

For the question of how much mercury is in canned tuna and canned fish, and how much is safe, this row is canned seafood with a tin flag, it does not name or rank retail brands, and the species measurements are on Canned Tuna and Tinned fish. Lima de Paiva et al. 2017 reported pooled mean methylmercury of 160 µg/kg in water-conserved canned tuna and 154 µg/kg in oil-conserved canned tuna, with water-conserved methylmercury from 41 to 460 µg/kg (Cadmium, lead, tin, total mercury, and methylmercury in canned tuna commercialised in São Paulo, Brazil, DOI 10.1080/19393210.2017.1311379); the generated table below prints a methylmercury mean of 160 ppb and a highest reported value of 460 ppb, and this answer does not convert those table units; the same table prints a tin mean of 59410 ppb and a highest reported tin value of 115870 ppb beside a detection note of 0 of 30 for Depaiva 2017, and this answer does not treat that pair as one measurement; Rüstemli and Tuncay 2026 reported oil-packed tin at a mean of 59.41 +/- 20.83 mg/kg wet weight (range 38.21 to 115.87 mg/kg) and oil-packed total mercury at 0.617 +/- 0.402 mg/kg wet weight (range 0.190 to 2.680 mg/kg) (Mineral and heavy metal content in canned tuna: Implications for veterinary public health and consumer safety, DOI 10.1007/s11259-026-11228-x). The filed guidance figures do not agree on one safe amount, and this page does not choose among them: the EPA IRIS oral reference dose is 0.1 µg methylmercury (MeHg)/kg b.w./day (Methylmercury (MeHg) — IRIS Chemical Assessment Summary, no DOI); the EFSA 2012 methylmercury tolerable weekly intake is 1.3 µg mercury (Hg)/kg b.w./week (Scientific Opinion on the Risk for Public Health Related to the Presence of Mercury and Methylmercury in Food, DOI 10.2903/j.efsa.2012.2985); the JECFA provisional tolerable weekly intake is 1.6 µg MeHg/kg b.w./week (Evaluation of Certain Food Additives and Contaminants (Methylmercury), 61st Meeting of JECFA, DOI 10.1016/s0168-1605(03)00167-3); Commission Regulation (EU) 2023/915 prints total mercury maximum levels of 1.0 mg/kg for muscle meat of listed predatory species including tuna, 0.50 mg/kg for crustaceans, molluscs, and other muscle meat of fish, and 0.30 mg/kg for a listed lower-mercury group, and the source page prints those levels with decimal commas (Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006, no DOI).

Reported measurements

Anwar and colleagues, canned tuna as packed, wet weight. Lead was below the method detection limit of 0.0001 mg/kg in every treatment. Total mercury treatment means, n=3: 121 C for 20 min in brine, 0.29 ± 0.164 mg/kg; 121 C for 20 min in palm oil, 0.58 ± 0.247 mg/kg; 115 C for 50 min in brine, 0.35 ± 0.042 mg/kg; 115 C for 50 min in palm oil, 0.39 ± 0.045 mg/kg. Pooled across 12 cans, individual replicates span 0.13 to 0.80 mg/kg, mean 0.40 mg/kg. The abstract reports 0.29 to 0.58 mg/kg, which the note says is the span of treatment means. This page repeats both ranges and does not choose one. The Indonesian SNI 8223:2016 maxima of 0.3 mg/kg lead and 1.0 mg/kg mercury are the authors’ comparators. Quality of Canned Tuna from Aceh Water Sterilized Using a Pressure Canner

Aquino Hancco and colleagues, canned tuna, mg/kg wet weight, n=25. Mercury was detectable in 14 of 25 samples. Mean among detects 0.0398 ± 0.0230, detect range 0.001 to 0.069, detect median 0.045, detect first to third quartile 0.0208 to 0.055. Cadmium detect range 0.033 to 0.269. Lead range not detected to 3.113, with one sample at 3.113. The results state a method detection limit of 0.008 mg/kg. Fresh-fish market samples in the same note are not canned tuna and are not repeated here. The note’s comparators of 0.5 mg/kg mercury, 0.10 mg/kg cadmium, and 0.30 mg/kg lead are the authors’ comparators. Dietary exposure figures in the same note are not product concentrations and are not repeated here. Determination Of Mercury, Cadmium, And Lead Levels In Canned Tuna And Fish Marketed In Central Lima, Peru, Using Atomic Absorption Spectrophotometry: Implications For Public Health

Lima de Paiva and colleagues, canned tuna, µg/kg wet weight. Water-conserved total mercury 51 to 460, pooled mean 173. Oil-conserved total mercury 44 to 402, pooled mean 169. Water-conserved methylmercury 41 to 460, pooled mean 160. Oil-conserved methylmercury 35 to 393, pooled mean 154. Methylmercury was 82 to 99 percent of total mercury across 30 samples. Cadmium overall not detected to 213. The note says the highest oil-conserved brand mean was about 85 µg/kg and a typical water-conserved brand mean was about 20 µg/kg. Twenty percent of the 15 oil-conserved samples exceeded 100 µg/kg cadmium. None of the water-conserved samples did. Lead: the narrative says water-conserved mean contents were below 30 µg/kg, while Table 2 brand means are 34 to 46 µg/kg for water-conserved tuna and 31 to 44 µg/kg for oil-conserved tuna. This page repeats both and does not choose one. Overall lead was not detected to 59.2 µg/kg. One oil-conserved brand row prints a methylmercury mean of 167 µg/kg beside a range of 103 to 158 µg/kg. This page repeats both and does not reorder them. Tin was not detected. The tin limit of detection is 94 µg/kg. Other limits of detection: cadmium 8.5, lead 30, total mercury 0.5, methylmercury 1.4 µg/kg. The 100 µg/kg cadmium and 300 µg/kg lead maxima are the authors’ comparators. Cadmium, lead, tin, total mercury, and methylmercury in canned tuna commercialised in São Paulo, Brazil

Rüstemli and Tuncay, canned tuna, mg/kg wet weight, n=105 (35 sauce-packed, 35 oil-packed, 35 water-packed). Aluminum: sauce 13.99 ± 5.42 (9.57 to 33.10), oil 18.67 ± 6.12 (10.83 to 33.94), water 13.65 ± 2.97 (9.31 to 19.67). Total chromium: sauce 0.47 ± 0.10 (0.26 to 0.89), oil 0.60 ± 0.34 (0.37 to 2.10), water 0.48 ± 0.09 (0.36 to 0.67). Chromium is not identified as hexavalent chromium. Nickel: sauce 0.379 ± 0.145 (0.148 to 0.989), oil 0.393 ± 0.238 (0.077 to 1.053), water 0.423 ± 0.115 (0.120 to 0.667). Total arsenic: sauce 0.782 ± 0.329 (0.310 to 1.867), oil 3.039 ± 1.525 (0.790 to 7.083), water 0.641 ± 0.177 (0.370 to 0.990). Speciation is not reported. Tin: sauce 39.52 ± 3.26 (34.00 to 44.79), oil 59.41 ± 20.83 (38.21 to 115.87), water 37.07 ± 2.92 (32.64 to 43.13). Total mercury: sauce 0.380 ± 0.283 (0.080 to 1.280), oil 0.617 ± 0.402 (0.190 to 2.680), water 0.153 ± 0.074 (0.060 to 0.380). Lead: sauce 0.094 ± 0.041 (0.050 to 0.270), oil 0.104 ± 0.055 (0.040 to 0.252), water 0.053 ± 0.026 (0.000 to 0.100). Total mercury exceeded the Turkish Food Codex 1.0 mg/kg limit in six samples: one sauce-packed sample at 1.28 mg/kg and five oil-packed samples at 1.05, 1.11, 1.20, 1.35, and 2.68 mg/kg. Three of those six also exceeded a Codex 1.2 mg/kg limit the note names (1.35, 2.68, and 1.28). Those limits are the authors’ comparators. All 105 samples were within the note’s 0.30 mg/kg lead and 200 mg/kg tin maxima. The note says total arsenic exceeded a 1.0 mg/kg guideline in 80 percent of sauce-packed, 100 percent of oil-packed, and 74.29 percent of water-packed samples, and it prints a sauce-packed mean of 0.782 ± 0.329 mg/kg. This page repeats both and does not choose one. The overall total-arsenic range is 0.31 to 7.08 mg/kg, overall mean 1.49 mg/kg, highest single value 7.08 mg/kg in oil-packed tuna. The note does not print a cadmium concentration. Mineral and heavy metal content in canned tuna: Implications for veterinary public health and consumer safety

Shim and colleagues, total mercury, ppb wet weight. Light tuna in water, 48 to 63, mean 54. Light tuna in vegetable oil, 174 to 191, mean 183. Light tuna in soy oil, 340. White or albacore tuna in water or pouch, 227 to 330, mean 263. White or albacore tuna in soy oil, 220. Canned salmon, 20 to 70, mean 45. Canned mackerel, 50 to 61, mean 55. Overall tuna mean, n=240, 188 ppb. Salmon mean, n=16, 45 ppb. Mackerel mean, n=16, 55 ppb. The limit of detection is 0.01 ng total mercury. The FDA action level of 1000 ppb methylmercury, expressed as mercury, is the authors’ comparator. The authors’ suggestion to use 185 ppb is their recommendation, not a concentration measured in a can. Fatty-acid figures in the same note are not metals and are not repeated here. Mercury and Fatty Acids in Canned Tuna, Salmon, and Mackerel

Canned seafood, arsenic species, and methylmercury demethylation

Canned seafood can carry arsenic that is often organic, plus mercury that may or may not be speciated as methylmercury, and tin from the can is a packaging question rather than a gut question. The studies below did not open a can and sequence stool. Inorganic arsenate experiments and hexavalent chromium gavage are different species from what a seafood panel usually reports as total arsenic and total chromium.

Sitarik et al. 2020 measured tooth lead and stool microbiota at 1 month and 6 months in 146 maternal-child pairs in the Detroit-area WHEALS cohort. In utero tooth lead was associated with fungal community composition at 1 month. Lead was not associated with overall bacterial community structure. Taxon-level bacterial shifts were higher Collinsella at 1 month, higher Bilophila at 6 months, and lower Bacteroides. The direction is lead exposure toward microbiota composition. Tooth lead is a biomarker, not a concentration in this product.

Eggers et al. 2023, per WikiBiome source summary, DOI 10.3389/fmicb.2023.1193919, followed 123 children in the Mexico City PROGRESS cohort. Maternal blood lead means were 33.6 µg/L in the second trimester and 34.9 µg/L in the third. Stool metagenomes at ages 9 to 11 showed lower Bacteroides caccae with lead exposure. Weighted quantile sum regression gave a negative overall mixture effect (beta = -0.17) in both trimesters. The direction is prenatal lead toward the childhood gut microbiota. The summary does not support a lead concentration in food.

Liu et al. 2023, per WikiBiome source summary, DOI 10.3389/fvets.2023.1219729, exposed Sprague-Dawley rats to cadmium chloride for 30 days. The note states lower intestinal ZO-1, higher TNF-alpha and IL-6 in intestine and blood, and Muribaculaceae in blood that was absent in the unexposed group. The note does not print the dose or the number of rats. The direction is cadmium toward gut and blood microbiota and barrier markers.

Hoen et al. 2018 related urinary total arsenic at 6 weeks to stool microbiota in 204 infants in the New Hampshire Birth Cohort Study. Urinary total arsenic had median 0.4 µg/L and mean 0.63 µg/L. Feeding-stratified means were 0.5 µg/L in exclusively breastfed infants, 0.9 µg/L in mixed-fed infants, and 1.2 µg/L in formula-only infants. Overall composition was marginally associated with natural-log urinary arsenic after adjustment for feeding and urine specific gravity (pseudo-F 1.85, p = 0.05). The clearest association was in formula-fed males (n = 33, pseudo-F 2.30, p = 0.008). Formula-fed females (n = 23) did not show that association. The direction is an early-life arsenic biomarker toward infant gut microbiota. Urinary arsenic is not a concentration in this product.

Dahan et al. 2018, per WikiBiome source summary, DOI 10.3389/fmicb.2018.01323, exposed larval zebrafish to 10, 50, and 100 ppb arsenic in water for 20 days. Arsenic exposure explained 54.7 percent of the variance in overall bacterial composition. The class 1 integron relative copy number at the highest concentration was 9 times the control value. The note does not state whether the dissolved arsenic was inorganic or total, and it does not give the number of larvae. The direction is arsenic in water toward the larval microbiome. The model is not a human gut, and the summary does not support an arsenic concentration in food.

Coe et al. 2023 paired a human cohort with gnotobiotic mice colonized with human microbiota. Gut microbes demethylated a fraction of ingested methylmercury, and the resulting inorganic mercury was preferentially excreted in feces rather than absorbed. Demethylation efficiency varied between people and was associated with taxa that carry mer operon machinery. The direction is gut microbiota toward methylmercury demethylation and elimination. The source page does not print one numeric fraction and does not give a methylmercury concentration in this product.

Giambo et al. 2021, per WikiBiome source summary, DOI 10.3892/wasj.2021.90, screened 600 articles and included 97. For mercury, the note states that methylation and demethylation are a core process in methylmercury metabolism and that microbiota changes have been linked to neurodevelopmental effects in rat offspring. The note does not assign a new sample size to that mercury summary. The direction summarized is microbiota toward methylmercury metabolism, and exposure toward microbiota in the offspring studies. The review does not test this product.

Xiong et al. 2025, per WikiBiome source summary, DOI 10.1038/s41467-025-60508-8, followed 146 mother-infant pairs, with maternal hair trace elements measured in 119 mothers. Shannon diversity of the infant gut at 3 months correlated positively with selenium and negatively with copper. Bifidobacterium relative abundance increased under high aluminum and high manganese together, so the note does not separate aluminum from manganese. The note states that high copper and arsenic may enrich antibiotic resistance genes. Hair concentrations are not printed. The direction is prenatal trace-element biomarkers toward the infant gut. Hair is not a food sample.

Mu et al. 2023 gavaged mice with potassium dichromate at 75 mg/kg for 29 days (n = 60 across three groups). Hexavalent chromium lowered Chao1 diversity from 170.75 ± 15.79 to 87.00 ± 9.55 (p = 0.00029) and Shannon diversity from 4.64 ± 0.68 to 2.64 ± 0.64 (p = 0.0055). Escherichia_Shigella rose from 10.71 percent to 57.75 percent. Seaweed polysaccharide at 200 mg/kg partly reversed the shift. The direction is hexavalent chromium toward gut microbiota. The dose is a gavage dose. It is not a total-chromium concentration in food.

Richardson et al. 2018, per WikiBiome source summary, DOI 10.1038/s41598-018-24931-w, gavaged Sprague-Dawley rats for 5 days with sodium arsenite, cadmium chloride, sodium dichromate, cobalt chloride, or nickel chloride, 5 rats per cohort. The note does not print the milligram doses. Observed OTUs and Shannon diversity were lower for arsenic, chromium, and nickel (p < 0.05). Differential genera numbered 37 for nickel, 17 for arsenic, 5 for cadmium, and 10 for chromium. Sodium dichromate is a hexavalent chromium salt, so the chromium arm is not a total-chromium result. The direction is short oral exposure toward the rat gut microbiota.

Yang et al. 2023 compared 109 occupationally nickel-exposed workers with matched controls. Serum nickel in the exposed group was 5.70 ± 3.21 µg/L, serum uric acid was 355.95 ± 67.87 µmol/L, and uric-acid-lowering bacteria, including Lactobacillus and related taxa, were lower. The direction is occupational nickel toward gut microbiota and then toward a host metabolite. Serum nickel is not a concentration in this product.

Study table

What remains uncertain

Coe and colleagues do not print one demethylated fraction and did not feed canned seafood. The mercury review does not add a can-lot result. Dahan and colleagues did not name the arsenic species. Hexavalent chromium gavage is not total chromium in fish or shellfish, and it is not tin. No study cited here sequenced stool after canned seafood.

Methodology

Reports what cited sources say about heavy-metal concentrations in this row. Speciation non-substitutable. Basis preserved.

References

Works cited in this page’s text, in first-appearance order. See Sources for this page’s source inventory. Each title links to a source record with bibliographic details, reported findings, and document provenance.

1. Cadmium, lead, tin, total mercury, and methylmercury in canned tuna commercialised in São Paulo, BrazilLima de Paiva E, Morgano MA, and Milani RF · Food Additives & Contaminants: Part B, Vol. 10, No. 3, pp 185–191 · 2017 · doi.org/10.1080/19393210.2017.1311379Peer-reviewed
2. Mineral and heavy metal content in canned tuna: Implications for veterinary public health and consumer safetyRüstemli N and Tuncay R M · Veterinary Research Communications · 2026 · doi.org/10.1007/s11259-026-11228-xPeer-reviewed
3. Methylmercury (MeHg) — IRIS Chemical Assessment SummaryU.S. Environmental Protection Agency · 2001 · iris.epa.govGovernment
4. Scientific Opinion on the Risk for Public Health Related to the Presence of Mercury and Methylmercury in FoodEFSA Panel on Contaminants in the Food Chain (CONTAM) · EFSA Journal 2012;10(12):2985 · 2012 · doi.org/10.2903/j.efsa.2012.2985Government
5. Evaluation of Certain Food Additives and Contaminants (Methylmercury), 61st Meeting of JECFAJoint FAO/WHO Expert Committee on Food Additives · WHO Technical Report Series 922 · 2004 · doi.org/10.1016/s0168-1605(03)00167-3Government
6. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006European Commission · Official Journal of the European Union · 2023 · eur-lex.europa.euRegulation
7. Quality of Canned Tuna from Aceh Water Sterilized Using a Pressure CannerAnwar S H, Hifdha R W, Rohaya S, and Hasan H · Jurnal Pascapanen dan Bioteknologi Kelautan dan Perikanan · 2021 · doi.org/10.15578/jpbkp.v16i1.705Peer-reviewed
8. Determination Of Mercury, Cadmium, And Lead Levels In Canned Tuna And Fish Marketed In Central Lima, Peru, Using Atomic Absorption Spectrophotometry: Implications For Public HealthGladys Aquino Hancco, Carlos Javier Solano Salinas, Pedro Munante Gomez, and Luis Alberto Lopez Avila · International Journal of Advanced Signal and Image Sciences · 2026 · xlescience.orgPeer-reviewed
9. Mercury and Fatty Acids in Canned Tuna, Salmon, and MackerelShim SM, Dorworth LE, Lasrado JA, and Santerre CR · Journal of Food Science · 2004 · doi.org/10.1111/j.1365-2621.2004.tb09915.xPeer-reviewed
10. Fetal and early postnatal lead exposure measured in teeth associates with infant gut microbiotaSitarik AR, Arora M, Austin C, Bielak LF, Eggers S, Johnson CC, et al. · Environment International · 2020 · doi.org/10.1016/j.envint.2020.106062Peer-reviewed
11. Prenatal lead exposure is negatively associated with the gut microbiome in childhoodEggers S, Midya V, Bixby M, Gennings C, Torres-Olascoaga LA, Walker RW, et al. · Frontiers in Microbiology · 2023 · doi.org/10.3389/fmicb.2023.1193919Peer-reviewed
12. Environmental cadmium exposure alters the internal microbiota and metabolome of Sprague-Dawley ratsLiu S, Deng X, Li Z, Zhou W, Wang G, Zhan J, et al. · Frontiers in Veterinary Science · 2023 · doi.org/10.3389/fvets.2023.1219729Peer-reviewed
13. Sex-specific associations of infants’ gut microbiome with arsenic exposureAnne G. Hoen, Juliette C. Madan, Zhigang Li, Modupe Coker, Sara N. Lundgren, Hilary G. Morrison, et al. · Scientific Reports · 2018 · doi.org/10.1038/s41598-018-30581-9Peer-reviewed
14. Exposure to arsenic alters the microbiome of larval zebrafishDahan D, Jude BA, Lamendella R, Keesing F, and Perron GG · Frontiers in Microbiology · 2018 · doi.org/10.3389/fmicb.2018.01323Peer-reviewed
15. Assessing the Role of the Gut Microbiome in Methylmercury Demethylation and Elimination in Humans and Gnotobiotic MiceGenevieve L. Coe, Ian N. Krout, Mason Munro-Ehrlich, Catherine R. Beamish, Daria Vorojeikina, Daniel R. Colman, et al. · Archives of Toxicology, Vol. 97, pp. 2399-2418 · 2023 · doi.org/10.1007/s00204-023-03548-7Peer-reviewed
16. Influence of toxic metal exposure on the gut microbiotaGiambo F, Italia S, Teodoro M, Briguglio G, Furnari N, Catanoso R, et al. · World Academy of Sciences Journal · 2021 · doi.org/10.3892/wasj.2021.90Peer-reviewed
17. Prenatal exposure to trace elements impacts mother-infant gut microbiome, metabolome and resistome during the first year of lifeXiong S, Xie B, Yin N, Zhu H, Gao H, Xu X, et al. · Nature Communications · 2025 · doi.org/10.1038/s41467-025-60508-8Peer-reviewed
18. Seaweed polysaccharide relieves hexavalent chromium-induced gut microbial homeostasisMu J, Guo Z, Wang X, Wang X, Fu Y, Li X, et al. · Frontiers in Microbiology · 2023 · doi.org/10.3389/fmicb.2022.1100988Peer-reviewed
19. Exposure to toxic metals triggers unique responses from the rat gut microbiotaRichardson JB, Dancy BCR, Horton CL, Lee YS, Madejczyk MS, Xu Z, et al. · Scientific Reports · 2018 · doi.org/10.1038/s41598-018-24931-wPeer-reviewed
20. Nickel exposure induces gut microbiome disorder and serum uric acid elevationJinfeng Yang, Pengya Feng, Zhenmin Ling, Aman Khan, Xing Wang, Yanli Chen, et al. · Environmental Pollution, Vol. 324, 121349 · 2023 · doi.org/10.1016/j.envpol.2023.121349Peer-reviewed

Sources

Source records associated with this topic. Inclusion does not establish that every finding applies to this product or ingredient. References above identify works cited in the text. Additional records await source or bibliographic review and are excluded from this list.

Update history

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