Are Scallops High or Low in Mercury? The Definitive Answer

According to U.S. Food and Drug Administration (FDA) data, scallops have one of the lowest average mercury concentrations of all commercial seafood, making them a safe and healthy choice. The reason for these low levels is their position low on the marine food chain, mitigating the risks associated with larger, predatory species.

Quick Summary

Scallops are low in mercury, confirmed by FDA data, due to their position as filter feeders low on the food chain. This makes them a safe and nutritious seafood option.

Key Points

• Low Mercury Content: FDA data confirms that scallops have one of the lowest average mercury concentrations of all commercial seafood (0.003 ppm).

• Low on the Food Chain: Scallops are filter feeders that eat plankton, preventing the significant bioaccumulation of mercury seen in larger predatory fish.

• Considered a 'Best Choice': Federal health agencies like the FDA and EPA classify scallops as a "Best Choice" due to their low mercury levels, making them safe for frequent consumption.

• Rich in Nutrients: Scallops are a high-protein, low-fat source of essential nutrients, including Vitamin B12, selenium, zinc, magnesium, and omega-3 fatty acids.

• Suitable for Vulnerable Groups: The low mercury content makes scallops a recommended seafood for pregnant and nursing women, as well as young children, in recommended quantities.

• Sourcing Matters: To minimize risk from other potential contaminants, it is always best to purchase scallops from reputable, safe sources.

Understanding Mercury Accumulation

Mercury is a naturally occurring element that can become a toxic environmental pollutant, most notably through industrial activities like coal-burning. In aquatic environments, bacteria convert elemental mercury into a highly toxic form called methylmercury. This methylmercury is absorbed by aquatic organisms and accumulates up the food chain in a process called biomagnification.

The Process of Biomagnification

• Tiny marine organisms like algae absorb small amounts of methylmercury from the water.
• Small fish eat these organisms, accumulating the mercury from all the prey they consume.
• Larger predatory fish then eat the smaller fish, further concentrating the toxin in their bodies.
• As a result, long-living, large predatory fish such as swordfish, shark, and king mackerel accumulate the highest levels of mercury.

Why Scallops Are a Low-Mercury Choice

Scallops are filter feeders that primarily consume plankton, placing them very low on the marine food chain. Because they do not prey on other fish, they do not undergo the biomagnification process that affects larger predators. This is why their mercury concentration remains exceptionally low. The U.S. Environmental Protection Agency (EPA) and FDA classify scallops as a "Best Choice" for consumption, recommending 2-3 servings per week for the general population and even for vulnerable groups like pregnant or nursing individuals.

Scallop vs. Other Seafood Mercury Levels

Data compiled by the FDA clearly shows that scallops contain significantly less mercury than many other popular seafood items. Below is a comparison table showcasing the average mercury concentration in parts per million (ppm) for scallops and other species, based on FDA records from 1990-2012.

Species	Average Mercury (ppm)	Mercury Category (Based on FDA/EPA Guidelines)
Scallop	0.003	Best Choice / Low Mercury
Shrimp	0.009	Best Choice / Low Mercury
Salmon (Fresh/Frozen)	0.022	Best Choice / Low Mercury
Cod	0.111	Good Choice / Medium Mercury
Halibut	0.241	Good Choice / Medium Mercury
Albacore Tuna (Canned)	0.350	Good Choice / Medium Mercury
Swordfish	0.995	Choices to Avoid / High Mercury
Shark	0.979	Choices to Avoid / High Mercury

Health Benefits and Considerations

Beyond their low mercury content, scallops offer a wealth of nutritional benefits, making them a valuable addition to a healthy diet. They are an excellent source of lean protein, which supports muscle growth and helps with weight management. Scallops are also rich in several vital nutrients:

• Vitamin B12: Crucial for nerve function and red blood cell formation.
• Selenium: A powerful antioxidant that supports thyroid function.
• Zinc: Essential for immune function and overall health.
• Magnesium and Potassium: These minerals help regulate blood pressure and promote heart health.
• Omega-3 Fatty Acids: Provide anti-inflammatory benefits that support heart and brain health.

Important Precautions for All Seafood

While scallops are a very low-risk option, all seafood consumption should be approached with general safety guidelines in mind. Always source your scallops from reputable suppliers to ensure they were harvested from clean waters. Individuals with shellfish allergies must avoid scallops entirely, as they are a common allergen. Although their mercury content is low, some studies suggest scallops may accumulate other heavy metals like cadmium depending on their environment, so consumption in moderation is always advised. For more detailed guidelines on safe seafood consumption, consult the FDA's official advice on eating fish.

Conclusion: Scallops Are a Safe, Low-Mercury Seafood

For those concerned about mercury in seafood, scallops are an excellent option. Their position as a filter feeder at the bottom of the marine food web means they accumulate very little methylmercury. Supported by federal health agency data, scallops can be confidently added to your diet as a nutrient-dense protein source. By choosing this low-mercury shellfish, you can enjoy the delicious taste and numerous health benefits without worrying about high mercury exposure.

Frequently Asked Questions

Are scallops a low-mercury seafood?

Yes, scallops are considered one of the lowest mercury options among commercially available seafood. Their position at the bottom of the food chain prevents the high mercury accumulation seen in larger, predatory fish.

How often can I safely eat scallops?

Federal health agencies recommend that most adults can safely eat 2-3 servings of low-mercury seafood like scallops per week. This includes vulnerable populations like pregnant and nursing women.

Do scallops contain any mercury at all?

Almost all fish and shellfish contain trace amounts of mercury due to environmental factors. However, the concentration in scallops is so minimal that it is not considered a health concern for most people when consumed in moderation.

Why do some fish have more mercury than others?

Larger, long-lived predatory fish accumulate more mercury through a process called biomagnification. They absorb the mercury from the smaller fish they eat, causing concentrations to increase up the food chain.

Are sea scallops or bay scallops lower in mercury?

Both sea scallops and bay scallops are considered low in mercury. Their different sizes and habitats do not significantly change their overall low-mercury status compared to other types of seafood.

Are there other health risks associated with eating scallops?

While mercury is not a major concern, scallops can pose a risk to individuals with shellfish allergies, which is one of the most common food allergens. Some regional variations may also expose them to other heavy metals, though overall, they are considered very safe.

How do scallops compare to other shellfish like shrimp and oysters?

Scallops are comparable in low mercury levels to other shellfish like shrimp and oysters. According to FDA data, all these shellfish have very low mercury concentrations and are considered safe choices.