Mercury poisoning facts*
*Mercury poisoning facts by John P. Cunha, DO, FACOEP
“Mercury is a naturally occurring element that is found in air, water and soil. A highly toxic form (methylmercury) builds up in fish, shellfish and animals that eat fish. Fish and shellfish are the main sources of methylmercury exposure to humans.
Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system. High levels of methylmercury in the bloodstream of unborn babies and young children may harm the developing nervous system, making the child less able to think and learn.
Symptoms of methylmercury poisoning may include impairment of peripheral vision; disturbances in sensations (“pins and needles” feelings); lack of coordination; impairment of speech, hearing, walking; and muscle weakness.
Elemental (metallic) mercury primarily causes health effects when it is breathed as a vapor where it can be absorbed through the lungs. Symptoms include tremors, emotional changes, insomnia, weakness, muscle atrophy, twitching, headaches, disturbances in sensations, changes in nerve responses, and performance deficits on tests of cognitive function. Higher exposures may result in kidney effects, respiratory failure and death.”
Consumer Reports, in its October 2014 issue, presents information about mercury in the fish we eat. It also advances the argument that the recent guidelines of the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) regarding how much fish is healthy to eat, especially by women and children, may lead to the consumption of too much mercury. The latest federal proposal is to increase the amount of fish eaten by women who are pregnant or trying to get pregnant to 8-12 ounces per week. Nevertheless, certain fish contain higher amounts of mercury than others, and meeting these fish consumption guidelines may lead to excessive amount of mercury intake.
The following is a list of fish based on mercury content:
Highest mercury fish (to be avoided by pregnant women, breast-feeding women, and children: Swordfish, shark, King Mackerel, gulf tilefish, marlin, orange roughy
Moderate mercury fish (whose consumption must be limited): Grouper, Chilean seabass, bluefish, halibut, sablefish (Black Cod), Spanish mackerel, fresh tuna.
Low mercury fish: Haddock, pollock, flounder and sole, catfish, trout, Atlantic mackerel, Atlantic croaker, mullet, crawfish, crab.
Lowest mercury fish: Wild and Alaska salmon (fresh or canned), shrimp, sardines, tilapia, scallops, oysters, squid.