How Do Fish "Absorb" Harmful Mercury?
Some large fish species tend to eat smaller fish that contain trace amounts of mercury. Consuming these fish leads to the accumulation of harmful toxins in the body.
However, certain types of fish contain very high levels of mercury, which is a concern for consumers' health. Mercury is a heavy metal naturally found in the environment, such as in the air, water, and soil.
This metal is released into the environment in various ways, such as through coal combustion, volcanic eruptions, and more. From there, mercury can fall from the air and accumulate in streams and oceans, eventually transforming into methylmercury in water.
Today, with environmental pollution being a growing concern, mercury levels in water have particularly risen, affecting the fish living in those waters. As a result, humans are at risk of mercury exposure in many ways—not only by inhaling mercury vapor through industrial activities but also through consuming fish that may contain mercury.
Many cases of mercury exposure have been caused by consuming fish that are contaminated with high levels of mercury beyond the acceptable limits. Over time, mercury can become highly toxic and seriously affect health, contributing to the development of brain and liver diseases, as well as increasing the risk of Alzheimer’s, Parkinson's, autism, depression, and more.
Which Fish Contain the Most Mercury?
Catfish
Did you know that large catfish are often farmed using hormones to increase their weight for higher profits? These fish are considered unclean and are at higher risk of absorbing harmful mercury, which should make you think twice before choosing them.
Ocean Perch
Unlike freshwater perch, ocean perch is classified by the U.S. Food and Drug Administration (FDA) as one of the fish species most susceptible to mercury contamination. This is because ocean perch live at the bottom of the ocean, where 80% of the mercury in the upper water layers is broken down by sunlight.
In addition, ocean perch are omnivores, which makes them more prone to accumulating various toxins and microorganisms from their aquatic environment. When consuming fish with high mercury content like ocean perch, these toxins can gradually build up in the human body. Long-term consumption may lead to mercury poisoning, causing damage to the mucous membranes in the mouth, teeth, and severe effects on the digestive system and kidneys.
Catfish (
Catfish is a type of fish that Vietnam has the opportunity to export, raising its economic value. However, when testing for the presence of crystal violet and malachite green in the United States, the results were not as expected. Unfortunately, the U.S. has listed catfish among the types of fish that are considered low quality and one of the eight fish species most contaminated with mercury, which you should be aware of.
Mackerel
Mackerel is a type of fish rich in omega-3 fatty acids, which are very beneficial for the development of young children and pregnant women. However, it is also a type of fish that can contain mercury, so it is important to research before consumption. Mackerel from the Atlantic Ocean is considered safe and a good choice.
Eel
Eels are a type of fish that are both easily contaminated with mercury and are considered unclean due to absorbing industrial and agricultural waste through water sources.
Which Fish Are Best for Health?
Studies have shown that fatty fish rich in omega-3 fatty acids can be beneficial for heart health. Omega-3 can also help reduce the risk of diseases such as strokes and Alzheimer’s disease.
Good sources of these healthy acids include: wild-caught salmon, herring, anchovies, sardines, and freshwater fish.