methylmercury

noun

meth·​yl·​mer·​cury ˌme-thəl-ˈmər-kyə-rē 

-ˈmər-k(ə-)rē

: any of various toxic compounds of mercury containing the complex CH₃Hg− that often occur as pollutants which accumulate in living organisms (such as fish) especially in higher levels of a food chain

Examples of methylmercury in a Sentence

Recent Examples on the Web

Salmon and its skin can contain low levels of methylmercury, a toxin that can be passed from the mother to her child. — Kait Hanson, Southern Living, 18 Sep. 2026

This methylmercury bioaccumulated in Minamata Bay’s fish and shellfish. — Encyclopedia Britannica, 3 Sep. 2026

Between September and December 2020, Xu replaced the contents of coffee capsules, whiskey bottles and water bottles in colleagues’ offices with methylmercury chloride, an acute toxin that can be fatal if swallowed, inhaled or touched. — Sylvie Zhuang, CNN Money, 28 May 2026

This decision was based on what levels were considered safe for methylmercury (the kind in fish), which is structurally very different from the ethylmercury found in thimerosal. — Lauren Gelman, Parents, 21 Nov. 2025

Word History

First Known Use

1915, in the meaning defined above

Rhymes for methylmercury

• mercury

Medical Definition

methylmercury

noun

meth·​yl·​mer·​cury

ˌmeth-əl-ˈmər-kyə-rē, British also ˌmē-ˌthīl-

plural methylmercuries

: any of various toxic compounds of mercury containing the complex CH₃Hg− that often occur as pollutants formed as industrial by-products or pesticide residues, tend to accumulate in living organisms (as fish) especially in higher levels of a food chain, are rapidly and easily absorbed through the human intestinal wall, and cause neurological dysfunction in humans see minamata disease