meth·​yl·​mer·​cury ˌme-thəl-ˈmər-kyə-rē How to pronounce methylmercury (audio)
: 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 According to the Center for Disease Control, large amounts of methylmercury (organic mercury largely linked to eating seafood, but mainly fish) eaten over weeks to months can cause damage to the nervous system. Vanessa Etienne, Peoplemag, 8 May 2024 Between September and December 2020, Mr. Xu began spiking beverages such as coffee, whiskey and drinking water with methylmercury chloride and bringing them into the office, Caixin reported, citing court documents. David Pierson, New York Times, 1 Apr. 2024 For example, when pregnant people eat fish contaminated with the organic form, methylmercury, the toxin can harm their fetuses. Bridget Alex, Smithsonian Magazine, 5 Mar. 2024 When mercury flows into bodies of water, bacteria can convert it into a form called methylmercury that is easily absorbed by small plants and animals, and accumulates in larger, older fish. Paul Rogers, The Mercury News, 25 Feb. 2024 Too much methylmercury in the body can cause problems with functions that involve nerves, like movement coordination and peripheral vision.9 Benefits of Eating Raw Fish Though there are risks with eating raw fish, having seafood as part of your diet can be beneficial. Susan Brickell, Health, 17 Aug. 2023 According to the World Health Organization, exposure to even a small amount of methylmercury can cause brain, lung and intestinal damage. Lila Levinson, Dallas News, 17 Aug. 2023 The more than 100 hydroelectric projects constructed in the Amazon over the last 50 years have enabled methylmercury levels in fish and humans to rise. Jill Langlois, Smithsonian Magazine, 21 Feb. 2023 The mummichog’s remarkable survival abilities were first recognized in the early 1970s, when the marine ecologist Judith S. Weis and her husband, Peddrick, decided to use the species to investigate the effects of the toxic chemical methylmercury on marine life. Carrie Arnold, The Atlantic, 15 Mar. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'methylmercury.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1915, in the meaning defined above

Time Traveler
The first known use of methylmercury was in 1915

Dictionary Entries Near methylmercury

Cite this Entry

“Methylmercury.” Dictionary, Merriam-Webster, Accessed 20 Jul. 2024.

Medical Definition


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
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