Heavy metals in Fish

Fish overview

Mercury decides most questions about fish, and the species on the plate matters far more than anything else that has been measured. Across European monitoring results compiled by EFSA, mean total mercury in fish muscle ran from about 31–35 µg/kg in salmon and trout and 32–44 µg/kg in sardine, through 91–96 µg/kg in cod and whiting and 286–291 µg/kg in tuna, to 688–695 µg/kg in shark and 1,210–1,214 µg/kg in swordfish (lower- to upper-bound means, wet weight).^{1EFSA Panel on Contaminants in the Food Chain (CONTAM) · 2012Scientific Opinion on the Risk for Public Health Related to the Presence of Mercury and Methylmercury in FoodEFSA Journal 2012;10(12):2985Read source →} WHO GEMS/Food submissions from Europe show the same order, with a median of about 184 µg/kg for tuna against 80 µg/kg for cod and 18–30 µg/kg for sardine.^{2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →}

Most of the mercury in fish muscle is methylmercury, the form that drives intake limits. In 210 retail fish samples from Japan, methylmercury made up about 60–90% of total mercury once total mercury was at least 100 µg/kg, close enough that total mercury is used as a screening measure.^{10Watanabe T, Hayashi T, Matsuda R, Akiyama H, Teshima R · 2017Surveillance of Total Mercury and Methylmercury Concentrations in Retail FishFood Hygiene and Safety ScienceRead source →} The EU sets 500 µg/kg of total mercury for most fish muscle and 1,000 µg/kg for large predators such as tuna, swordfish and shark, while Codex sets methylmercury levels of 1,200 µg/kg for tuna and 1,600 µg/kg for shark.^{9Codex Alimentarius Commission, Codex Committee on Contaminants in Foods · 2024Report of the 17th Session of the Codex Committee on Contaminants in Foods (REP24/CF17)Joint FAO/WHO Food Standards Programme, Codex Alimentarius CommissionRead source →11European Commission · 2023Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006Official Journal of the European UnionRead source →}

Lead and cadmium are usually low in fish muscle where monitoring is routine, and arsenic in fish is mostly in organic forms. US Total Diet Study composites of baked cod, salmon and tilapia had lead below 4 µg/kg and cadmium at or below about 1 µg/kg, and EFSA’s European fish muscle data gave a cadmium median of 5 µg/kg.^{3U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →12EFSA Panel on Contaminants in the Food Chain (CONTAM) · 2009Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the European Commission on cadmium in foodThe EFSA JournalRead source →} Total arsenic in marine fish is often in the thousands of µg/kg, such as 4,500 µg/kg in US baked cod, but inorganic arsenic averaged only 0.7–20 µg/kg (lower bound) across European fish species.^{3U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →4European Food Safety Authority (EFSA) · 2014Dietary exposure to inorganic arsenic in the European populationEFSA Journal 2014;12(3):3597Read source →}

Higher lead and cadmium values come mostly from small surveys of rivers, lagoons and coasts near mining, industry or wastewater, and many of the most extreme ones fail checks against their own papers.^{13Shaalan WM · 2024Hazardous effects of heavy metal pollution on Nile tilapia in the aquatic ecosystem of the Eastern Delta in EgyptBMC Veterinary ResearchRead source →14Torabi S, Gholizadeh M, Yazarlo M, Riahi Z · 2024Health Risk Assessment of Heavy Metals in Marine Fish Caught from the Northwest Persian GulfBiological Trace Element ResearchRead source →15Ray S, Francis GA, Pathak SS, Chavan P, Vashishth R · 2025ICP-MS-based quantitative analysis and risk assessment of metal(loid)s in fish species from Chennai, IndiaFrontiers in Public HealthRead source →} For a buyer or a regular eater, the supported priorities are species and size choice for mercury, verified lot results for the analyte that applies to the species, and keeping total and inorganic arsenic apart.^{8U.S. Food and Drug Administration, U.S. Environmental Protection Agency · 2017Advice About Eating Fish — For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1 to 11 YearsU.S. FDA and U.S. EPARead source →11European Commission · 2023Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006Official Journal of the European UnionRead source →16European Commission · 2025Commission Regulation (EU) 2025/1891 of 17 September 2025 amending Regulation (EU) 2023/915 as regards maximum levels of inorganic arsenic in fish and other seafoodOfficial Journal of the European UnionRead source →}

What counts as fish on this page

This page covers finfish eaten by people: the muscle, fillet or whole small fish of marine, freshwater and farmed species, and the canned, smoked, dried, salted, fermented and processed products made from them.^{2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →3U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →11European Commission · 2023Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006Official Journal of the European UnionRead source →} Fish oils and fish-liver oils, fish sauce and fish products such as fingers, cakes and collagen supplements are kept as separate forms and never pooled with flesh.^{17Torović L, Banović Fuentes J, Stanojković N, Lukić D, Djermanović M · 2024Mercury Content in Fish Oil Food Supplements and Associated Health RiskProceedings 2023, 91, 364 (MDPI Proceedings — 14th European Nutrition Conference FENS 2023)Read source →18Brodziak-Dopierała B, Fischer A, Chrzanowska M, Ahnert B · 2023Mercury Exposure from the Consumption of Dietary Supplements Containing Vegetable, Cod Liver, and Shark Liver OilsInternational Journal of Environmental Research and Public HealthRead source →19Matsumoto-Tanibuchi E, Sugimoto T, Kawaguchi T, Sakakibara N, Yamashita M · 2019Determination of Inorganic Arsenic in Seaweed and Seafood by LC-ICP-MS: Method ValidationJournal of AOAC InternationalRead source →}

Shellfish, crustaceans, cephalopods, marine mammals, fish feed and fish offal are outside the scope, as are fish-containing infant foods, which have their own product page.^{2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →20Meli MA, Desideri D, Sisti D, Fagiolino I, Roselli C · 2024Chemical characterization of baby food consumed in ItalyPLOS ONERead source →} Categories that mix finfish with shellfish, common in total diet studies and some European summaries, are also excluded because their results cannot be attributed to fish.^{2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →21European Commission Directorate-General Health and Consumer Protection, SCOOP Task 3.2.11 experts · 2004Assessment of the dietary exposure to arsenic, cadmium, lead and mercury of the population of the EU Member StatesReports on tasks for scientific cooperation, SCOOP Task 3.2.11Read source →}

Measurements are kept in the basis the source reports: wet weight (as sold or eaten), dry weight, or basis not stated; dry-weight results are not converted without the paper’s own moisture data.^{6Unknown authors · 2020PCBs and Heavy Metals in Farmed, Escaped and WildPeer-reviewed articleRead source →7Abbas MMM · 2023Heavy Metal Levels and Cancer Risk Assessments of the Commercial Denis, Sparus aurata Collected from Bardawil Lake and Private Fish Farm Waters as a Cultured Source, EgyptNot reportedRead source →} Total mercury, methylmercury and mercury of unstated form are separate analytes, as are total, inorganic and organic arsenic species.^{4European Food Safety Authority (EFSA) · 2014Dietary exposure to inorganic arsenic in the European populationEFSA Journal 2014;12(3):3597Read source →10Watanabe T, Hayashi T, Matsuda R, Akiyama H, Teshima R · 2017Surveillance of Total Mercury and Methylmercury Concentrations in Retail FishFood Hygiene and Safety ScienceRead source →22Brooke PJ, Evans WH · 1981Determination of Total Inorganic Arsenic in Fish, Shellfish and Fish ProductsAnalystRead source →}

Heavy metal contamination profile of fish

The table holds every finfish result extracted from about 250 monitoring datasets, total diet studies and surveys: one row for each statistic a source reports for a species group, form, site and metal, so a mean, a median and a range from the same fish appear as separate rows.^{1EFSA Panel on Contaminants in the Food Chain (CONTAM) · 2012Scientific Opinion on the Risk for Public Health Related to the Presence of Mercury and Methylmercury in FoodEFSA Journal 2012;10(12):2985Read source →2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →3U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →12EFSA Panel on Contaminants in the Food Chain (CONTAM) · 2009Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the European Commission on cadmium in foodThe EFSA JournalRead source →} Ratings place a reported mean, median or sample value against an HMI reference built only from the same species group, preparation form, analyte and basis; non-detects remain intervals and are never read as zero.^{2World Health Organization · 2026GEMS/Food Contaminants database heavy-metal exportsGEMS/Food Contamination Monitoring and Assessment ProgrammeRead source →3U.S. Food and Drug Administration · 2022FY2018-FY2020 TDS Elements Analytical ResultsFDA Total Diet StudyRead source →10Watanabe T, Hayashi T, Matsuda R, Akiyama H, Teshima R · 2017Surveillance of Total Mercury and Methylmercury Concentrations in Retail FishFood Hygiene and Safety ScienceRead source →} Rows that failed a check against their own paper stay visible with the specific reason and are not compared.^{13Shaalan WM · 2024Hazardous effects of heavy metal pollution on Nile tilapia in the aquatic ecosystem of the Eastern Delta in EgyptBMC Veterinary ResearchRead source →14Torabi S, Gholizadeh M, Yazarlo M, Riahi Z · 2024Health Risk Assessment of Heavy Metals in Marine Fish Caught from the Northwest Persian GulfBiological Trace Element ResearchRead source →15Ray S, Francis GA, Pathak SS, Chavan P, Vashishth R · 2025ICP-MS-based quantitative analysis and risk assessment of metal(loid)s in fish species from Chennai, IndiaFrontiers in Public HealthRead source →}