Ethylmercury (sometimes ethyl mercury) is a cation composed of an organic CH3CH2- species (an ethyl group) bound to a mercury(II) centre, making it a type of organometallic cation, and giving it a chemical formula C2H5Hg+. The main source of ethylmercury is thimerosal.[1]
Ethylmercury (C2H5Hg+) is a substituent of compounds: it occurs as a component of compounds of the formula C2H5HgX where X = chloride, thiolate, or another organic group. Most famously X = the mercaptide group of thiosalicylic acid as in thiomersal. In the body, ethylmercury is most commonly encountered as derivatives with a thiolate attached to the mercury.[2] In these compounds, Hg(II) has a linear or sometimes trigonal coordination geometry. Given the comparable electronegativities of mercury and carbon, the mercury-carbon bond is described as covalent.[3]Шаблон:Rp
Toxicity
The toxicity of ethylmercury is well studied.[4][1] Like methylmercury, ethylmercury distributes to all body tissues, crossing the blood–brain barrier and the placental barrier, and ethylmercury also moves freely throughout the body.[5] Risk assessment for effects on the human nervous system have been made by extrapolating from dose-response relationships for methylmercury.[1] Estimates have suggested that ethylmercury clears from blood with a half-life of 3–7 days in adult humans; however, this area has not been well studied.[6][7]
Public health concerns
Шаблон:Main
Concerns based on extrapolations of the effect of methylmercury caused thimerosal to be removed from U.S. childhood vaccines in 1999, but it remains in use in all multi-dose vaccines and flu shots (though many single use vaccines without thimerosal are available).[8] Researchers have argued that risk assessments based on methylmercury were overly conservative in light of observations that ethylmercury is eliminated from the body and the brain significantly faster than methylmercury.[1] Moreover, the same researchers have argued that inorganic mercury metabolized from ethylmercury, despite its much longer half-life in the brain, is much less toxic than the inorganic mercury produced from mercury vapor, for reasons not yet understood.[1]
