Protecting Public Health and the Environment.
Mercury is a naturally occurring metallic element that is 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. It is slowly released through erosion and weathering into surface waters. Most of the mercury in surface waters remains inorganic, but in favorable 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 also can settle into soil and rivers, lakes, and oceans, where aquatic microbes convert it to methylmercury through a biochemical reaction.
Methylmercury tends to accumulate in the tissue of fish as it passes over their gills and 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 thus is of particular interest from a human health standpoint. By far the most common route of mercury exposure in humans is eating fish contaminated by methylmercury, according to the federal Centers for Disease Control.
To help protect public health, the Idaho Division of Health through the Idaho Fish Consumption Advisory Program issues fish consumption advisories when fish in water bodies in Idaho 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.
It is important to note that fish consumption advisories don't mean you should stop eating fish from affected water bodies, just that you should be aware of the risks. 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 CoordinatorDon EssigDEQ State Office1410 N. HiltonBoise, ID 83706(208) firstname.lastname@example.org
Health Effects of Methylmercury
Mercury and Air QualityMercury Pollution Prevention