Arsenic as a contaminant
Arsenic is a naturally occurring metalloid widely recognized as a contaminant. It exists in both inorganic and organic forms and is found at low concentrations in rocks, soil and groundwater. The inorganic form (I-As) is of particular concern, as scientific assessments have consistently linked it to skin lesions and cancers of the lung, bladder and skin.[i]
Human activity has significantly increased arsenic levels in the environment. I-As is used across several industrial sectors, mainly for metal alloy hardening, glass manufacturing, electronics and semiconductor applications and as a catalyst in the production of ethylene oxide. Arsenic compounds are also used as a mordant in textile processing, for hide preservation and as medicinals, pesticides, pigments and wood preservatives.[ii] Their release pollutes estuaries and coastal waters, further intensifying natural background levels.
The ecological consequences are severe. Arsenic exposure harms aquatic organisms and leads to bioaccumulation in seafood and seaweed. I-As also accumulates more rapidly in animal tissues than organic arsenic, according to a 2025 study in India.[iii] This increased rate of accumulation and higher toxicity make seafood contamination a pressing concern for both environmental health and consumer safety.
EU regulatory action
On September 17, 2025, the European Union (EU) released Commission Regulation 2025/1891, amending its food contaminant rules under Regulation 2023/915. The update sets new maximum levels for inorganic arsenic (I-As) in fish and other seafood, marking a significant step in tightening consumer safety standards across the EU.
This regulation is applicable to all Member States.
Other heavy metals in seafood
Arsenic is just one of several heavy metal contaminants commonly found in fish and seafood, including mercury (Hg), lead (Pb) and cadmium (Cd). Like arsenic, these are harmful to human health and the environment, and they enter aquatic systems via both anthropogenic pollution and natural emissions, such as volcanic activity.
- Mercury: a highly toxic element that can cause damage to the nervous, digestive and immune systems, lungs, kidneys, skin and eyes of humans. Pregnant women and young children are particularly vulnerable. EU[iv] and US[v] studies show that large predatory fish (e.g. swordfish, sharks, tunas and grouper) often contain mercury levels above EU regulatory limits due to bioaccumulation
- Lead: can enter seafood through contaminated water and sediments. It is linked to cardiovascular problems and cognitive deficits, especially in children. Mollusk bivalves, which filter large volumes of water, often concentrate lead above EU regulatory limits
- Cadmium: accumulates mainly in shellfish such as mollusk bivalves and cephalopods, with lower risks in fish. According to the World Health Organization (WHO), chronic exposure can cause damage to the kidneys as well as the skeletal and respiratory systems. It is classified as a human carcinogen[vi]
Proper regulation and awareness of heavy metal levels in seafood are essential for protecting public health. Programs and guidelines help consumers make informed decisions, but ongoing monitoring is critical to ensuring safety. In Europe, heavy metals are a leading cause of food-safety alerts reported by Member States through the Rapid Alert System Food and Feed (RASFF) system, accounting for around 20% of cases between 2023 and 2025.
| EU RASFF | 2023 | 2024 | 2025 (Jan-Oct) |
| Heavy metals | 76 | 97 | 57 |
| Mercury (Hg) | 58 | 66 | 44 |
| Cadmium (Cd) | 13 | 28 | 11 |
| Lead (Pb) | 0 | 0 | 2 |
| Arsenic (As) | 1 | 3 | 0 |
Monitoring results
Between 2014 and 2023, official controls analyzed more than 5,800 seafood samples for heavy metals – 4,300 for Hg, 3,340 for Cd and 2,170 for Pb. Results showed:
- Mercury: marine fish with total mercury concentrations above the legal limits were primarily swordfish (11% non-compliant), sharks (6.5%) and tuna species (3%). Freshwater fish had significantly lower mercury levels
- Cadmium: cephalopods showed the highest mean concentration of 0.15mg/kg with standard deviation of +/- 0.38 mg/kg, indicating a wide range of results, and the highest absolute value detected (5.60 mg/kg identified in an oceanic squid)
- Lead: bivalves exhibited the highest mean concentration of 0.13 mg/kg with a standard deviation of +/- 0.16 mg/kg, indicating variability in results, with notable levels also observed in echinoderms, while fish samples consistently remained below detectable limits[vii]
Maximum residue limits
The EU, US, China and FAO Codex recommend the following maximum residue limits.
| Maximum limit in mg/kg(edible part of the seafood) | |||||
| EU Regulation (2023 & 2025) | US FDA & USDA (2022) | China GB2762-2022 | FAO Codex 193 (2021) | ||
Mercury (Hg) | Fish* | 1 (tuna, swordfish), 0.3 (salmon, cod, saithe, plaice, mackerel...) | Methylmercury: 1 All fish & seafood | Methylmercury: 1.2 (tuna), 1.5 (shark),1 (carnivorous fish), 0.5 to 1.7 (other) | Methylmercury: 0.8 to 1.7 1.2 (tuna) |
| Crustacean | 0.5 | 0.5 | NA | ||
| Mollusk | 0.3 | 0.5 | NA | ||
Cadmium (Cd) | Fish* | Depends on the species: 0.05 - 0.1, 0.15-0.25 | 0.01 (Siluriformes) | 0.2 (canned fish), 0.1 (other fish products) | NA |
| Crustacean* | 0.5 | NA | 3 (sea crab, mantis shrimp), 0.5 (others) | NA | |
| Mollusk | 1 | NA | 2 | 2 | |
Lead (Pb) | Fish* | 0.3 | 0.025 (Siluriformes) | 0.5 | 0.3 |
| Crustacean* | 0.5 | NA | 0.5 | NA | |
| Mollusk* | 1.5 (bivalves), 0.3 (cephalopods) | NA | 1.5 (bivalves), 0.5 (cephalopods) | NA | |
Inorganic arsenic (I-As) | Fish* | 0.1, except listed species: 0.5 | NA | 0.1 | NA |
| Crustacean | 0.1 (crab), 0.2 (shrimp), 1.5 (lobster) | 0.5 | |||
| Mollusk | 0.1 (scallops), 0.5 (other bivalves), 0.05 (cephalopods) | 0.5 | |||
*Limit depends on the species defined in EU or China regulation
SGS solutions
Ensure seafood safety with trusted testing. Our global network of food testing facilities covers all major seafood-producing countries, providing accredited analysis of heavy metals using inductively coupled plasma mass spectrometry (ICP-MS) or cold-vapor atomic absorption spectrometry (CVAAS) to deliver results aligned with EU regulatory limits.
We apply liquid chromatography ICP-MS, a specialized method that identifies key species of I-As. When requesting testing, it is important to specify whether you require total arsenic or I-As analysis.
Our experts help seafood businesses navigate complex requirements and ensure their products meet international standards with confidence. Contact us to ensure your seafood products meet the latest standards.
For further information, please contact:
Laurent Galloux
Seafood program development manager
Health & Nutrition
t: +33607755758
[i] Update of the risk assessment of inorganic arsenic in food
[ii] IRIS Toxicological Review of Inorganic Arsenic (Final Report, 2025) | IRIS | US EPA
[iii] A systematic review on arsenic toxicity and its impacts on fish species | Cornous Biology
[iv] Monitoring of Cadmium, Lead, and Mercury Levels in Seafood Products: A Ten-Year Analysis
[v] Mercury Levels in Commercial Fish and Shellfish (1990-2012) | FDA
[vi] Chemical Safety and Health
[vii] Monitoring of Cadmium, Lead, and Mercury Levels in Seafood Products: A Ten-Year Analysis
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