Foods High in Mercury

What is mercury?

Mercury is alternatively referred to as hydragyrum or quicksilver.  It is the only metal that appears in liquid state at room temperature. Mercury occurs naturally in the environment and is found in air, soil, and water.  Nowadays, increased emission of mercury also comes from man-made sources. With Hg as its chemical symbol, mercury is a good conductor of electricity, and it gets easily evaporated into the air. Further, a unique property of mercury is that it can be combined with other metals.

This heavy metal exists in a variety of forms such as elemental mercury, organic mercury, and inorganic mercury. The purest form of mercury – elemental mercury cannot be combined with other metals, and its prime usage is to produce caustic soda and chlorine gas. In the case of organic mercury, it is formed when mercury is combined with carbon, and an example for which is methylmercury. This, in turn, is formed naturally in soil as well as water. When it comes to inorganic mercury, it occurs when mercury is blended with inorganic elements such as chlorine, oxygen, and sulfur. This form of mercury is mostly seen in items including antiseptics, disinfectants, fungicides, ointments, and skin fairness creams.  

Even though it can cause adverse affects on human beings as well as other living organisms, mercury’s usage is considered effective for the manufacture of teething powder and herbicides that is designed to kill weeds.

How is mercury harmful to us?

A neurotoxin metal, Mercury can be harmful to both humans and animals. The health problems as a result of mercury are based on several factors such as how it got in your body and how long you have been exposed to this metal. Living organisms usually get exposed to mercury through direct skin contacts, intake of water of food contaminated with mercury, and breathing vapors. Children are more prone to mercury poisoning when compared to adults. There are also instances in which exposure to mercury affects pregnant women, thereby hindering the development of a healthy fetus. Mercury is also sometimes transmitted to newborns through breast feeding. According to the studies, the exposure to even a small quantity of mercury can adversely affect your health by causing damage to your brain, lungs, and kidney.

Mercury exposure symptoms

If you are exposed to mercury, your body may show certain signs and symptoms, depending on how much mercury has entered your body, such as:

• Loss of appetite
• Behavioral changes
• Abdominal cramps
• Eye irritation
• Diarrhea
• Skin irritations
• Muscle tremors
• Nausea
• Fatigue and insomnia

Majority of the symptoms will disappear when the exposure to mercury is decreased or stopped. However, it may sometimes cause permanent ill-effects to the brain and nervous system.

What foods are high in mercury?

Foods with moderate amounts of mercury

Foods with the least amount of mercury (safe foods)

Anchovies, herring, sardine, butterfish, mackerel (N. Atlantic, Chub), scallop, catfish, shad (American), clam, mullet, shrimp, crab, oyster, sole (Pacific), crawfish, perch, squid, croaker (Atlantic), plaice, tilapia, flounder, pollock, trout (freshwater), haddock (Atlantic), salmon (canned), whitefish, hake, salmon (Fresh), whiting

What types of tuna should I buy that has the lowest amount of mercury?

Tips for the prevention of mercury pollution

• Reduce the usage of mercury lamps
• Use digital and LCD forehead thermometers
• Stick on to the usage of mercury free items
• Replace incandescent light bulbs with energy efficient fluorescent bulbs or CFL’s. The newest CFL’s have extremely low mercury content.
• Avoid consumption of food items that contain high level of mercury.

Summary

Top the list of foods that are high in mercury are seafood items. Although every fish absorbs mercury from water, predator fish such as king mackerel, shark, swordfish, and tile fish contain high content of mercury. This is due to the effects of bioaccumulation. Some types of tuna including albacore also contain mercury. Hence, the FDA and EPA recommend the consumption of fish low in mercury like catfish, salmon, and Pollock. Apart from these, food items sweetened with high fructose corn syrup, such as ketchup and sodas, also contain high level of mercury. One of the best ways to keep away from the food items that contain mercury is to carefully check the list of ingredients in food items.

More info on mercury in fish visit nrdc.org/mercury