Is salmon high in heavy metals?

December 10, 2025 •

3 min read

According to the FDA, fresh and frozen salmon average just 0.022 parts per million (ppm) of mercury, placing it among the 'Best Choices' for consumption. But is salmon high in heavy metals beyond mercury, and are there differences between wild and farmed varieties? This guide addresses these concerns, providing context on safety and health.

Quick Summary

Both farmed and wild salmon typically contain low heavy metal concentrations, including mercury, with most levels well below international safety limits. The health benefits of eating salmon generally outweigh the minimal risks associated with low-level contaminants.

Key Points

Low Mercury Content: Salmon is low in mercury compared to larger, longer-lived fish, and the FDA considers it a 'Best Choice' for consumption.
Selenium Protection: Natural selenium in salmon binds to mercury, neutralizing its toxicity and offering a protective health benefit.
Organic Arsenic is Less Harmful: The arsenic in salmon is mostly the non-toxic, organic form (arsenobetaine), which is safely eliminated by the body.
Wild vs. Farmed Differences: While there are slight variations in contaminant levels, both wild and farmed salmon are generally safe, with modern farmed salmon being much cleaner than in the past.
Benefits Outweigh Risks: The numerous health benefits of consuming salmon, particularly its omega-3 fatty acids, far exceed the risks posed by its low contaminant levels for most people.
Informed Choices Are Key: Varying your diet, choosing responsible sources, and preparing fish properly can further reduce any minimal risk associated with contaminants.

Understanding Heavy Metals in Seafood

Heavy metals enter marine environments through a combination of natural processes and human activities. These metals accumulate in the aquatic food chain, potentially increasing in concentration in larger, predatory fish through biomagnification. Agencies like the FDA and EPA regulate maximum safe levels for contaminants in seafood.

Mercury in Salmon: The FDA's Take

Mercury is a primary heavy metal concern in seafood, but the FDA considers salmon a 'Best Choice' due to its low levels. Salmon's position in the food chain and shorter lifespan limit mercury accumulation compared to larger predators. FDA data shows very low average mercury concentrations in both fresh/frozen (0.022 ppm) and canned (0.014 ppm) salmon. The FDA and EPA recommend 2 to 3 servings of low-mercury fish like salmon weekly, especially for sensitive groups.

The Arsenic Reality: Organic vs. Inorganic

Arsenic is also found in seafood. However, the arsenic in marine organisms like salmon is mainly the organic form, arsenobetaine, which is considered virtually non-toxic and easily eliminated by the body. This distinguishes it from highly toxic inorganic arsenic.

The Selenium Advantage: Nature's Protector

Selenium, an essential mineral in salmon, can protect against mercury toxicity. Selenium binds strongly to mercury, forming a stable, non-toxic complex (mercury-selenide) that the body can safely handle. Research indicates that selenium levels often exceed mercury in fish like salmon, providing a protective effect.

Wild vs. Farmed Salmon: Heavy Metal Comparison

While past concerns existed about contaminants like PCBs in farmed salmon, modern feed and regulations have significantly reduced these levels. Differences in heavy metal levels between wild and farmed salmon exist but are often minor and within safe limits. Farmed salmon might show slightly higher non-toxic organic arsenic, while wild might have marginally more mercury; however, both remain safe choices.

Comparison of Wild vs. Farmed Salmon (Heavy Metals)


Feature	Wild Salmon	Farmed Salmon
Mercury Levels	Generally low, potentially slightly higher than farmed.	Consistently low, levels well below safety limits.
Organic Arsenic	Often lower than in farmed salmon.	Can be higher due to feed ingredients, but primarily the non-toxic form.
Cadmium	May have slightly higher levels.	Low or near undetectable in muscle tissue.
PCBs & Dioxins	Present at low levels; generally lower than historical farmed levels.	Significantly reduced due to modern feed and regulations.

Practical Tips for Safe Salmon Consumption

The nutritional benefits of salmon typically outweigh the minimal risks from contaminants. To ensure safe consumption:

Vary your fish: Eating different types of fish reduces exposure from one source.
Source wisely: Wild Alaskan salmon is often noted for being lower in contaminants.
Choose certified farmed salmon: Look for certifications indicating responsible aquaculture.
Prepare properly: Trimming fat and removing skin can reduce fat-soluble contaminants.
Follow health advice: Adhere to consumption guidelines, especially for vulnerable populations.

Conclusion

Contrary to some concerns, salmon is not considered high in heavy metals for most consumers. It contains low levels of mercury and other metals, placing it among recommended fish choices. The natural presence of selenium further helps protect against potential mercury toxicity. While minor differences exist between wild and farmed salmon regarding contaminants, both are generally safe options, largely due to improvements in farming practices. By diversifying seafood intake, selecting fish from reliable sources, and following health guidelines, the substantial health benefits of salmon can be enjoyed with confidence. For official advisories on fish consumption, consult the FDA's Advice About Eating Fish.

Frequently Asked Questions

No, mercury levels in salmon are consistently low, falling well within safety guidelines established by the FDA and EPA. Salmon is not a high-mercury fish like shark or swordfish. Additionally, salmon contains selenium, which helps protect against any potential mercury toxicity.

Both wild and farmed salmon contain safe levels of heavy metals. Historically, farmed salmon sometimes had higher levels of PCBs and dioxins, but modern feed and regulations have significantly reduced this concern. While some studies show very slight differences in mercury or arsenic levels, they remain well below health thresholds for both types.

Selenium found in salmon plays a vital protective role by binding to mercury. This process forms a new, inert compound that neutralizes mercury's toxicity, rendering it harmless to the body. This interaction is a key reason why eating salmon is safe despite the presence of trace contaminants.

The arsenic found in salmon is almost entirely in its organic form, specifically arsenobetaine, which is considered non-toxic to humans. The body easily and quickly eliminates this compound, unlike the highly toxic inorganic arsenic found in some other environmental sources.

For most adults, health organizations like the American Heart Association recommend at least two servings of fatty fish, including salmon, per week. For pregnant women and young children, the FDA and EPA recommend 2-3 servings per week of low-mercury fish. Given its low heavy metal content, salmon is safe for frequent consumption within these guidelines.

Cooking does not significantly reduce mercury levels in fish. However, some fat-soluble contaminants, like older PCBs, are found primarily in the fat. Therefore, trimming the fat and removing the skin before cooking can help minimize exposure to those specific pollutants, especially in older farmed salmon.

Yes, for the vast majority of the population, the health benefits of eating salmon and other fish outweigh the minimal risks from low-level contaminants. Salmon is a rich source of omega-3 fatty acids, high-quality protein, and beneficial vitamins and minerals that support brain and heart health.