The Quick Facts: Mercury is a toxic metal that can damage children’s developing nervous system and may result in negative impacts ranging from neurological defects to learning disabilities. Mercury and its potential health impacts have come to the forefront with a number of findings made in the last few years: Oceana, an ocean-advocacy environmental group, found high levels of mercury in nationwide samples of sushi tuna; FDA changed its stance on the safety of mercury in amalgam teeth fillings seeking comments on whether they pose a health risk; researchers found detectable levels of mercury in samples of commercial high-fructose corn syrup (HFCS), the sweetener used in packaged foods and soft drinks. This is an evolving issue so it is important to stay informed about future findings on mercury. However, to date, there are three major sources from which you can reduce your exposure to mercury: seafood, dental fillings, and HFCS. Solutions include: avoid consumption of fish found to be high in mercury; avoid or reduce consumption of products containing HFCS; stay informed about FDA’s decision on dental fillings; switch to a renewable energy supplier of electricity to reduce the burning of coal and consequent deposition of mercury; conserve energy; properly dispose of products containing mercury.
NOTE: The information that follows has been adapted from Real Mama’s past articles to provide a primer and update on mercury, potential health risks, and possible exposure pathways. See also Tuna Fish: Is it Mercury in a Can? and Something Fishy: The challenge of balancing the nutritional value of fish with the risk of contaminant exposure and environmental costs
Risks of Mercury Exposure to Young Children and Women
Children and fetuses are highly susceptible to the effects of mercury because their bodies are still developing and mercury may have neurotoxic effects on the nervous systems of developing children. Studies show that the adverse health effects associated with mercury exposure in humans and animals include: neurological defects such as numbness in the arms and legs, slurred speech and difficultly walking. In children, developmental effects may also include learning disabilities and difficultly paying attention.
The U.S. Environmental Protection Agency (EPA) has estimated that one in six U.S. women of childbearing age has mercury levels in her blood high enough to put her baby at risk. The EPA and the U.S. Food and Drug Agency (FDA) have issued a joint warning to pregnant women, women who may become pregnant, and nursing mothers, which warns against eating shark, swordfish, king mackerel, and tilefish as they have been found to contain high levels of mercury. The EPA and the FDA further advise that such women, as well as children, should limit their intake of fish that contain low-levels of mercury (e.g., shrimp, canned light tuna, salmon, pollock, and catfish) to 12 ounces (2 average meals) a week and limit their intake of albacore (“white”) tuna (which has more mercury than canned light tuna) to 6 ounces (1 average meal) a week.
In addition, 45 states and territories have issued warnings advising people not to consume fish from local lakes, rivers, and coastal areas due to unsafe levels of mercury in some of the waterways. Accordingly, fish caught by family and friends at local lakes, rivers, and coastal areas should be checked against local advisories. If no advisories are available, the EPA advises pregnant women and children to eat no more than 6 ounces (one average meal) per week of such fish.
Sources of Mercury Exposure
According to the Sierra Club, mercury is a toxic metal that is released into the environment from natural sources such as volcanoes and from man-made sources such as power plants, silver-colored amalgam dental fillings, vaccinations that contain the preservative Thimerosal (See Real Mama’s article entitled “The Safety of Vaccines: Fears and Facts about Thimerosal-Containing Vaccines”) broken thermometers, and occupational exposures.
However, the major source of mercury releases into the environment is the burning of coal at power plants to generate electricity. Once released into the atmosphere, mercury falls to the earth in rain droplets and runs into our lakes, rivers, streams, and ultimately into the ocean. Through this process mercury is converted to methylmercury, a highly toxic substance, which binds to fish protein. According to the EPA, nearly all fish and shellfish contain traces of mercury. Larger fish (e.g., shark, swordfish, king mackerel) that have lived longer and eat other fish, have the highest levels of methylmercury because they have had more time to accumulate it. Importantly, this type of mercury cannot be eliminated through the cooking process.
Oceana, an ocean-advocacy environmental group, recently published a new report on mercury levels in popular fish and sushi entitled “Hold the Mercury.” The report includes the results of mercury tests on 94 fish samples collected by Oceana staff and volunteers from sushi bars and grocery stores in cities across the country. High levels of mercury were found in fresh tuna and swordfish as well as sushi prepared from such fishes. The group advocates for the need to post the FDA’s guidance to pregnant women and children about consuming seafood that may contain mercury in grocery stores.
In addition, the FDA recently published a proposed rule to classify dental amalgam as a class II device with special controls indicating a concern about the mercury found in them. FDA regulates dental amalgams as medical devices and is responsible for ensuring that they are reasonably safe, effective, and labeled with adequate directions or appropriate warnings. When amalgam fillings are placed in teeth or removed from teeth, they release mercury vapor. Mercury vapor is also released during chewing. On April 28, 2008, FDA reopened the comment period for a 2002 proposed rule to examine evidence about whether the release of mercury vapor from such dental fillings can cause health problems, including neurological disorders, in children and fetuses. By July 28, 2008, FDA is requesting comments, supported by empirical data and scientific evidence, concerning this classification and using special controls (changing materials and labeling) for dental amalgam.
Most alarming, a former FDA researcher named Renee Dufault published a study entitled “Mercury from chlor-alkali plants: measured concentrations in food product sugar” in the peer-reviewed Environmental Health Journal finding mercury in nearly half of high-fructose corn syrup (HFCS) samples collected in 2005. Another study conducted by the Institute for Agriculture and Trade Policy entitled “Not So Sweet: Missing Mercury and High Fructose Corn Syrup” found traces of mercury in one-third of HFCS-containing products its researchers pulled off of supermarket shelves last year.
The IATP study took products from supermarket shelves that contain HFCS including some of America’s leading food companies: Kraft, Hershey’s, Hunt’s, Smucker’s, General Mills, Coca-Cola, etc., and analyzed them for total mercury (not methylmercury). Detectable mercury was found in 17 of 55 samples, or around 31 percent. An Appendix of products tested is included with detected amounts of mercury. For example, Quaker Oatmeal on the Go and Kellogg’s Nutri-Grain bars had detectable levels of mercury. The main thrust of the study is that detectable amounts of mercury have been found right off our supermarket shelves.
http://www.iatp.org/iatp/publications.cfm?accountID=421&refID=105026 (Institute for Agricultural Trade and Policy study entitled “Not So Sweet: Missing Mercury and High Fructose Corn Syrup”)
Both studies suggest that mercury is seeping into HFCS through an industrial substance called caustic soda that is used by HFCS producers to break down corn. Caustic soda (also known as sodium hydroxide or lye) is produced in industrial chlorine (chlor-alkali) plants. “Mercury-grade” caustic soda comes from chlorine plants still using an outdated 19th century technology that relies on the use of mercury. This “mercury-grade” caustic soda is being phased out in favor of a new kind made without the toxic heavy metal. However, according to the IATP study, 10 percent of U.S. caustic soda comes from four remaining mercury-using plants and 60 percent of caustic soda production in Europe relies on mercury. Importantly, there are no restrictions on importing products made with HFCS into the United States. According to the U.S. Department of Agriculture, the average American consumes 40 pounds of HFCS every year.
Solutions To Reduce Mercury in Our Bodies and Our Environment
This is an evolving issue so it is important to stay informed about future findings on mercury. However, to date, there are three major sources from which reduce your exposure to mercury: seafood, dental fillings, and HFCS.
According to the EPA and the FDA, if you regularly eat seafood high in methylmercury, the methylmercury can stay in your body and accumulate overtime. Based on the recent Oceana study finding mercury in sushi from nationwide supermarkets, the FDA decision seeking comments on mercury in dental amalgam fillings, and the research on high-fructose corn syrup finding detectable levels of mercury in packaged products such as Kellogg’s Nutri-Grain Bars, even those who do not consume large amounts of fish may have been exposed to mercury. With time, methylmercury will be removed naturally; however, it may take over a year for the levels to drop significantly. If you have been exceeding the EPA and the FDA recommendations for fish and shellfish consumption, as described above, or want to reduce the level of mercury in your body for other reasons, here are some things you can do:
- Avoid mercury-containing fish.
- Avoid or reduce consumption of products containing HFCS.
- Stay informed about FDA’s decision on dental fillings.
- Switch to a renewable energy supplier of electricity to reduce the burning of coal. By reducing the input of mercury into the environment you will be reducing your exposure. For a list of renewable energy suppliers in your area go to www.green-e.org.
- Conserve energy whenever possible. Turn off lights when you leave the room, and when replacing electric appliances buy Energy Star approved products. Conserving energy will help to reduce the input of mercury into the environment by coal-burning electric suppliers.
- Properly dispose of mercury containing products. Some products such as fluorescent lamps contain mercury vapor and must be disposed of in accordance with local hazardous waste disposal rules or else the vapor will be released into the atmosphere and may ultimately end up on your plate.
Information used in this article was found at the following sources, which you can visit if you want to find out more about this topic:
http://www.epa.gov/waterscience/fish/MethylmercuryBrochure.pdf (Brochure from the FDA and EPA advising pregnant and nursing women and children to limit seafood consumption)
http://www.sierraclub.org/mercury/factsheets/ (Fact sheet from the Sierra Club, a national non-profit environmental organization dedicated to exploring, enjoying, and protecting the wild places of the earth, entitled “We Can Protect American Women and Children from Mercury Pollution)
http://books.nap.edu/catalog/9899.html (National Academy of Sciences book published in 2000 entitled “Toxicological Effects of Methylmercury”)
http://www.oceana.org/north-america/what-we-do/stop-seafood-contamination/reports-resources/hold-the-mercury/ (Oceana’s Report: Hold the Mercury)
http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DentalProducts/DentalAmalgams/default.htm (FDA Questions and Answers on Dental Amalgam)
http://www.ehjournal.net/content/8/1/2 (Environmental Health study entitled “Mercury from chlor-alkali plants: measured concentrations in food product sugar”)
http://www.iatp.org/iatp/publications.cfm?accountID=421&refID=105026 (Institute for Agricultural Trade and Policy study entitled “Not So Sweet: Missing Mercury and High Fructose Corn Syrup”)
http://www.EnergyStar.gov (ENERGY STAR is a government-backed program helping businesses and individuals protect the environment through superior energy efficiency)
