What Do You Know About Mercury in Fish?
Nearly all fish and shellfish contain traces of mercury, according to the EPA and the FDA. Find out how much you know about mercury contamination in fish by taking this quiz.
1. The amount of mercury in the atmosphere has increased steadily since:
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Mercury is a liquid metal used in thermometers, barometers, blood pressure devices, antiseptic compounds, and fungicides. With the rise of manufacturing in the Industrial Revolution, the production of mercury increased. Because liquid mercury can vaporize directly into the atmosphere, the more mercury that is manufactured, the more that evaporates.
2. Mercury in its elemental form is relatively nontoxic. In the environment, however, the elemental form of mercury is transformed into an organic form, which is easily absorbed by living things. This organic form, which builds up in the body, is called:
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Methylmercury is an organic form of mercury that accumulates in the food chain. It becomes increasingly concentrated in the animals at the top of the food chain and thus causes them the most harm. Methylmercury accounts for more than 95 percent of the mercury found in food fish.
3. Concentrations of methylmercury are highest in which of these ocean dwellers:
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Tuna are a large predatory fish at the top of the food chain, where methylmercury tends to concentrate. Plankton is tiny food for almost all small (and some large) marine animals. Smaller marine animals are food for bigger marine animals. As mercury moves up the chain, the larger fish and the longest-lived fish accumulate the mercury that has been absorbed by the smaller plants and animals.
4. People are more likely to ingest significant quantities of methylmercury by eating:
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Again, the higher up the food chain you eat, the greater the concentrations of mercury tend to be. Tuna are high on the food chain.
5. Mercury is most harmful to:
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The fetus is the most sensitive to the toxic effect of mercury. Unfortunately, the damage done to a fetus by mercury appears to be irreversible even when the exposure to mercury is removed. Although mercury is always toxic, it becomes less destructive with age. An adult is able to tolerate higher exposure without apparent adverse effects when compared with a fetus, child, or adolescent.
6. Mercury monitoring in local waterbodies falls under the jurisdiction of:
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State and tribal health programs regularly issue fish consumption advisories regarding how much fish a person can safely eat from certain lakes, rivers, and coastal waters without developing mercury toxicity.
7. About what percentage of women of childbearing age have mercury levels above those considered safe by the EPA?
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About 8 percent of women of childbearing age were found to have levels of mercury above the suggested upper safe limit. Women contemplating pregnancy might want to consider giving up fish (particularly if they eat a lot of fish). Methylmercury is eliminated from the body slowly and has a half-life of approximately 70 days. That means if you stopped all exposure to mercury, in 70 days you would have only half the original level of mercury and in 140 days only one-fourth the level.
8. High levels of methylmercury can cause:
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Mercury damages the brain and can cause a broad spectrum of neurological problems. One of the worst exposures in history was at Minamata Bay, Japan, where hundreds of pregnant women consumed fish contaminated with methylmercury. Their children were born with devastating neurological handicaps.
9. The FDA has recommended that pregnant and breastfeeding women, and children NOT EAT ANY of which fish?
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Since Jan. 1, 2001, the FDA has determined that shark, swordfish, king mackerel, and tile-fish have such high levels of mercury that pregnant women, women who are breastfeeding, and young children should not have even a single serving of these types of fish.
10. To reduce the effects of methylmercury toxicity on the fetus, the FDA recommends that pregnant women limit their WEEKLY intake of marine fish (fish from the ocean) to:
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11. To reduce the effects of methylmercury toxicity on the fetus, the EPA recommends that pregnant women limit their WEEKLY intake of freshwater fish (fish from rivers, streams, lakes, and reservoirs) to:
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This is approximately half the amount allowed for marine fish. It is important to take into account the type of fish and where they were caught. Some areas are so polluted that fishing is prohibited. You should check with your state health department if you are unsure about the pollution status of the area where the fish were caught.
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