Recently, the Food and Drug Administration (FDA) warned against eating certain large, long-lived predator fish due to high levels of mercury. The Washington Department of Health (DOH) and the health agencies of several other states also advise women of childbearing age and children under six to limit the amount of tuna they eat for the same reason. Too much mercury can have health impacts on everyone, but women of childbearing age and children under six are especially at risk. Methylmercury is the form of mercury that commonly contaminates fish. It is found in many kinds of fish, especially large fish that eat smaller fish, and in fish that live long lives. Because of health concerns due to mercury in fish, DOH has issued a statewide fish advisory. Fish Consumption Recommendations The Washington State Department of Health provides the following advice for women of childbearing age and children under six. For commercially bought fish: Do not eat any shark, swordfish, tilefish, king mackerel or either fresh caught or frozen tuna steaks. Limit the amount of canned tuna you eat, based on your bodyweight. General guidelines are: Women of childbearing age should limit the amount of canned tuna they eat to about one can per week (six ounces). A woman who weighs less than 135 pounds should eat less than one can of tuna per week. Children under six should eat less than one half a can of tuna (three ounces) per week. Specific weekly limits for children under six range from one ounce for a twenty pound child, to three ounces for a child weighing about sixty pounds. Choose chunk light tuna over albacore white to further reduce your exposure to mercury. Review a chart of recommended limits of canned tuna for different bodyweights. For freshwater bass: Woman of childbearing age and children under six should limit their consumption of freshwater bass (largemouth and smallmouth) to no more than 2 meals/month. Additional information can be obtained from the "Statewide Bass Advisory" report and the "Freshwater Largemouth and Smallmouth Bass Consumption Advisory Due to Mercury Contamination" fact sheet. Health problems caused by mercury are: Babies whose mothers ate fish contaminated with mercury during pregnancy, are at greater risk for changes to their nervous systems. These changes can affect their ability to learn. In adults, several neurological signs and symptoms are among the common features of chronic high-dose exposures to methylmercury in adults. These can include peripheral neuropathy (tingling in the hands and feet), tremor, problems walking, dizziness, visual and hearing difficulties, and memory impairment (NRC 2000, ATSDR 1999). These symptoms are generally not associated with the level of exposure to methylmercury through the consumption of fish in the U.S. Mercury has been shown to accumulate in the heart. Recent findings investigating chronic low-dose exposures have been associated with changes in blood-pressure and abnormal heart function (Salonen et al. 1995, Sorensen et al 1999) as well as increased risk of heart-attack (Guallar et al. 2002). Mercury contamination is a worldwide problem. It can come from many sources. It occurs naturally in the environment in rocks, soils, water and air. Volcanoes may also be a source of mercury in the environment. It can come from industrial pollution, especially the burning of coal and other fossil fuels and from burning household or industrial wastes. Though statewide data on mercury contamination of fresh water fish is limited, nationally it appears to show that bass, pike and walleye have higher levels of mercury than other species. Other Contaminants and Local Fish Advisories Contaminants other than mercury may be a problem for fish in certain areas of Washington state. But unlike mercury, the amounts of contaminants like PCBs and many pesticides are stored mostly in the fat of fish, and so they can be reduced by preparing it in ways that reduce the fat. Refer to the "Preparing Fish" website for details on how to prepare fish. Learn about specific "Fish Advisories" which might exist for fish from the rivers or lakes where you live by contacting your local health department. You can also review information about these local fish advisories at the DOH Local Fish Advisory Website.