Great Value Chunk Light Tuna, like nearly all tuna products, can contain some mercury. Mercury is naturally present in the environment and can accumulate in fish over time. The important question is not whether the tuna contains any mercury, but how much it is likely to contain and how often it is eaten.

Chunk light tuna is generally considered a lower-mercury choice than white or albacore tuna. However, lower mercury does not mean mercury-free.

Why Tuna Contains Mercury

Mercury can enter oceans through natural processes and human activities. In water, some mercury is converted into methylmercury, which can be absorbed by small aquatic organisms.

Small fish eat those organisms, and larger fish eat the smaller fish. As mercury moves through the food chain, it can build up in fish tissue. Larger and longer-lived predatory fish usually accumulate more mercury than smaller, shorter-lived fish.

Tuna are predators, so all tuna species may contain methylmercury to some degree.

Why Chunk Light Tuna Is Usually Lower in Mercury

Chunk light tuna is often made from smaller tuna species such as skipjack. Skipjack tuna generally grow quickly, remain smaller and live for less time than larger species such as albacore or bigeye tuna.

Because skipjack have less time to accumulate mercury and eat fewer contaminated prey over their lives, they usually contain less mercury than larger tuna species.

The exact species used in Great Value Chunk Light Tuna may vary by product and market. Consumers should check the ingredient list or package information to see whether the species is identified.

Great Value Tuna Is Not Mercury-Free

The Great Value brand does not make tuna biologically different from other canned tuna. If the product contains tuna, it may contain mercury because mercury is found in the fish before it is canned.

Canning does not create mercury, but it also does not remove it. Mercury binds to proteins in the fish tissue, so draining the water or oil does not eliminate most of it.

The amount in an individual can can vary because mercury levels differ among fish, even within the same species.

Is It Safe to Eat?

For most healthy adults, moderate consumption of canned light tuna can fit into a balanced diet. The risk depends on serving size, frequency, body weight and the amount of other mercury-containing seafood eaten.

Eating one moderate serving occasionally is very different from eating several cans every day. Frequent, high-volume consumption creates greater mercury exposure over time.

Pregnant people, those who may become pregnant, breastfeeding individuals and young children should follow official seafood-consumption guidance because developing nervous systems are more sensitive to mercury.

Light Tuna Compared With Albacore Tuna

Canned light tuna generally contains less mercury than canned white tuna, which is usually made from albacore.

Albacore tuna are typically larger and live longer than skipjack, allowing more mercury to accumulate. Bigeye tuna may contain even higher amounts and is generally not considered a good choice for frequent consumption.

For someone who eats canned tuna regularly, chunk light tuna is usually the more cautious choice.

Nutrition and Other Considerations

Great Value Chunk Light Tuna can provide a substantial amount of protein at a relatively low cost. It may also contain vitamin B12, selenium and niacin.

Mercury is not the only factor to consider. Some canned tuna products are high in sodium, so checking the nutrition label is useful. Choosing lower-sodium varieties and rotating tuna with other protein sources can improve dietary balance.

Alternatives include eggs, chicken, beans, lentils, sardines, salmon, tofu and dairy products.

Conclusion

Great Value Chunk Light Tuna can contain mercury because all tuna may contain some methylmercury. However, chunk light tuna is often made from smaller species and generally contains less mercury than albacore or bigeye tuna.

It should not be described as mercury-free, but it also should not automatically be considered unsafe. Moderate portions, attention to the species on the label and variety in the diet are the most practical ways to manage mercury exposure.