Component of many rocks and is released continually, but very slowly into natural waters by normal chemical weathering processes. Small quantities vaporize into the atmosphere from mercury-containing rocks. In bodies of water hg Settle at the body and adhere to sediment. Mercury is used int eh production of chemiscals, paints, plastics, pharmaceuticals, steel, electrical equipment. fungicides.
Elemental mercury not readily absorbed. Anaerobic bacteria in the bottom convert these forms of mercury to organic methyl mercury ion which is very soluble and readily absorbed.
Can damage nervous system, kidneys, liver birth defects.
1800s that the phrase "mad as a hatter" was coined because of the chronic mercury exposure that the felters faced because mercury was used in hat making. Mercury toxicity in environmental pollution is a major concern because of increased usage of fossil fuels and agricultural products, both of which contain mercury. inorganic form can be further divided into elemental mercury and mercuric salts. Organic mercury can be found in long and short alkyl and aryl compounds. Mercury in any form is toxic. The difference lies in how it is absorbed, the clinical signs and symptoms, and the response to treatment modalities. Mercury poisoning can result from vapor inhalation, ingestion, injection, or absorption through the skin. Neurologic, gastrointestinal, and renal systems are the most commonly affected organ systems in mercury exposur
Environmental Protection Agency (EPA) reduced the allowable intake of methylmercury from 0.5 ug to 0.1 ug of mercury per kilogram per day potential toxic effects (30,000 ng/g; Thompson, 1996). Smith and Armstrong (1975) reported Innuit sled dogs, subsisting largely on seal meat,which had levels ofHg, up to 11,500 ng/g in the liver, without apparent harm. Themean values of THg for theYukonRiver village sled dogs exceed the no effects hazard concentrations for river otters (660 ng/g) and
50 ppm = 50,000 ng/g Mercury EPA upper allowable limit of 0.1 ug/kg of body weight WHO safe value of 50 ppm hair EPA, WHO, FDA suggest maximum consumption of 226 g of fish per week for a 70 kg person
Mercury and climate change
& climate change
University of Alaska Fairbanks
of wild AK
•WHO Upper Allowable Threshold of 50
•EPA suggests a maximum consumption
of fish per week for a 70 kg person
•Reported adverse effects as low as
of 226 g
•Russian Mission sled dogs have some of the
highest reported mercury concentrations of any Alaskan