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Methylmercury (CH3Hg+)
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Elemental Mercury (Hg0)
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Mercuric Mercury (Hg2+)
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Sources of Exposure
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Fish, marine mammals, crustaceans, animals and poultry fed fish meal
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Dental amalgams, occupational exposure, Caribbean religious ceremonies, fossil fuels, incinerators
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Oxidation of elemental mercury or demethylation of MeHg; deliberate or accidental poisoning with HgCl2
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Biological Monitoring
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Hair, blood, cord blood
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Urine, blood
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Urine, blood
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Toxicokinetics
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Absorption
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Inhalation: Vapors of MeHg absorbed
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Inhalation: Approximately 80% of inhaled dose of Hg0 readily absorbed
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Inhalation: Aerosols of HgCl2 absorbed
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Oral: Approximately 95% of MeHg in fish readily absorbed from GI tract
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Oral: GI absorption of metallic Hg is poor; any released vapor in GI tract converted to mercuric sulfide and excreted
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Oral; 7-15% of ingested dose of HgCl2 absorbed from the GI tract; absorption proportional to water solubility of mercuric salt; uptake by neonates greater than adults
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Dermal: In guinea pigs, 3-5% of applied dose absorbed in 5 hr
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Dermal: Average rate of absorption of Hg0 through human skin, 0.024 ng/cm2 for every 1 mg/m3 in air
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Dermal: In guinea pigs, 2-3% of applied dose of HgCl2 absorbed
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Distribution
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Distributed throughout body since lipophilic; approximately 1-10% of absorbed oral dose of MeHg distributed to blood; 90% of blood MeHg in RBCs
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Rapidly distributed throughout the body since it is lipophilic
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Highest accumulation in kidney; fraction of dose retained in kidney dose dependent
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