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

When mercury reaches an aquatic environment, microorganisms like sulfate-reducing bacteria often convert it into a more toxic form of the element known as methylmercury. —Caroline Tien, SELF, 22 Apr. 2025

When tested on pregnant mice, the researchers similarly found lower levels of methylmercury in maternal and fetal tissues and lower signs of mercury toxicity in the fetal brain. —Lindsey Choo, Forbes.com, 6 May 2025

Eating fish containing methylmercury is actually the most common mercury exposure route in the US, per the EPA. —Caroline Tien, SELF, 22 Apr. 2025

Humans who eat fish that have eaten smaller aquatic life with methylmercury in their bodies can potentially be exposed to dangerous levels of methylmercury that acts like a neurotoxin. —Mack Degeurin, Popular Science, 12 Feb. 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