Protecting Public Health and the Environment.
Mercury is a naturally occurring metallic element found in trace amounts in air, water, and soil. Mercury is toxic to both aquatic life and humans, but its toxicity is primarily a human health concern.
Inorganic mercury occurs naturally due to its presence in rocks and soils, where it is slowly released through erosion and weathering into surface waters. Most of the mercury in surface waters remains inorganic, but in certain environments (low pH, low dissolved oxygen, and high organic matter, such as are found in the bottoms of lakes, marshes, and wetlands), some of it is converted to a much more toxic organic form—methylmercury. Airborne mercury from coal-fired power plants, mining operations, and other industrial sources can settle into soil and rivers, lakes, and oceans, where aquatic microbes convert it to methylmercury through a biochemical reaction. Elemental mercury released to the atmosphere can circulate around the world. The mercury people are exposed to comes not just from locally caught fish, but also, and for some primarily, from fish and shellfish caught elsewhere and sold in the market. Mercury pollution is truly a global problem.
Methylmercury tends to accumulate in the tissue of fish as they feed on other aquatic organisms. As larger fish eat smaller ones, concentrations of the pollutant increase in the bigger fish, a process known as bioaccumulation. Thus, mercury enters the food chain and becomes concentrated and is of particular interest from a human health standpoint. By far the most common route of mercury exposure in humans is eating fish and shellfish contaminated by methylmercury, according to the federal Centers for Disease Control.
To help protect public health, the Idaho Department of Health and Welfare through the Idaho Fish Consumption Advisory Program issues fish consumption advisories when fish in Idaho water bodies are found to have methylmercury levels above what is considered safe. The need for fish consumption advisories for some Idaho water bodies indicates that mercury pollution is a factor in Idaho, as do the results of water quality studies that show some water bodies in Idaho are impaired and fail to meet water quality standards for mercury.
Fish consumption advisories don't mean you should stop eating fish from affected water bodies, just that you should be aware of the risks and may need to limit your consumption to be safe. Fish are a good source of protein and low in saturated fat. Simply limit fish consumption to amounts specified in the advisory.
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Water Quality Standards LeadDon EssigDEQ State OfficeWater Quality Division1410 N. HiltonBoise, ID 83706(208) firstname.lastname@example.org
Health Effects of Methylmercury
Mercury and Air QualityMercury Pollution Prevention