chemical information


Chemical Class:


Found in these people:

Anonymous Adult 2, Anonymous Adult 3, Anonymous Adult 5, Anonymous Adult 4, Anonymous Adult 6, Anonymous Adult 7, Anonymous Teen 1, Anonymous Adult 9, Anonymous Adult 12, Anonymous Adult 13, Anonymous Adult 11, Anonymous Adult 10, Anonymous Adult 14, Anonymous Adult 15, Anonymous Adult 16, Anonymous Adult 17, Anonymous Adult 18, Anonymous Adult 20, Anonymous Adult 21, Andrea Martin, Bill Moyers, Davis Baltz, Lucy Waletsky, Michael Lerner, Sharyle Patton, Lexi Rome, Charlotte Brody, Baby #1, Baby #2, Baby #3, Baby #4, Baby #5, Baby #6, Baby #7, Baby #8, Baby #9, Baby #10, Anonymous Adult 1, Kathy Fowler, U.S. Representative Louise Slaughter, Participant #2, Participant #8, Kelsey Wirth, Michael Goodstein, Margie Roswell, Nina Damato, Nora Pouillon, Stephanie Berger, Participant #1, Participant #10, Fred Gellert, Adelaide Gomer, Ann Hunter-Welborn, Jesse Johnson, Anonymous Adult, Winsome McIntosh, Judi Shils, Participant #18, Lynde Uihlein, Participant #2, Participant #20, Jessica Welborn, Alicia Wittink, Irene Crowe, Martha Davis, Emily Sayrs, Participant #6, Anonymous Adult RN7, Anonymous Teen 22, Anonymous Adult RN9, Dr. Beverly Wright, Adult #108, Adult B, Vivian Chang, Jennifer Hill-Kelley, Jean Salone, Cord Blood Sample 11, Cord Blood Sample 12, Cord Blood Sample 13, Cord Blood Sample 14, Cord Blood Sample 15, Cord Blood Sample 16, Cord Blood Sample 17, Cord Blood Sample 18, Cord Blood Sample 19, Cord Blood Sample 20

Found in these locations:

Chicago, IL; Newton, MA; Fredericksburg, VA; Washington, DC; New York, NY; Lamont, FL; Atlanta, GA; Mountain View, CA; Stanford, CA; Palo Alto, CA; San Francisco, CA; Berkeley, CA; Alamo, CA; Fallbrook, CA; Sausalito, CA; NJ, USA; Pleasantville, NY; Bolinas, CA; Mill Valley, CA; Round Hill, VA; Rockville, MD; Upstate New York, NY; Silver Spring, MD; Cambridge, MA; Bethesda, MD; Baltimore, MD; CA, USA; Belvedere, CA; Ithaca, NY; Encinitas, CA; Ross, CA; VA, USA; Milwaukee, WI; CO, USA; Littleton, CO; MD, USA; New Orleans, LA; Oakland, CA; Green Bay, WI; Corpus Christi, TX

Exposure routes:

Primarily from dietary sources, particularly seafood.


Methylmercury (MeHg) is toxic to the developing fetal brain, and exposure in the womb can cause learning deficiencies and can delay mental development in children. The U.S. Centers for Disease Control (CDC) recently reported 10 percent of American women of childbearing age - some 7 million women - already have mercury in their blood at levels that the National Academy of Sciences considers potentially unsafe for the developing fetus. Most women are exposed to methylmercury through seafood, which accumulates the metal, much of which is released to the environment from the burning of coal at coal fired power plants.

Knowledge of the neurological effects in humans following developmental exposure to MeHg is based on accidental poisonings (in Japan and Iraq) and studies looking at groups of people whose diets are high in MeHg contaminated fish. These studies show that high exposure levels can lead to: spontaneous abortion; limb deformities; impaired growth; neurotoxicity (mental retardation, seizures, cerebral palsy); blindness and deafness. Lower exposure levels during development are associated with delays in cognitive developmental, abnormal muscle tone, and impaired reflex response.

Methylmercury is classified as being a 'possible' human carcinogen; it is associated with leukemia and possibly with liver cancer and chromosomal damage. Methylmercury exposure is also associated with changes in immune system (cell number, possible increased autoimmune response); kidney effects; decreased fertility and possible cardiovascular effects (increased blood pressure, heart attack) (NAS 2000).

In laboratory animals, the nervous system is the primary target of MeHg, especially when exposure occurs during development. Specific effects include impaired spatial development, visual recognition, play behavior and decreased activity. Other effects include kidney toxicity, immunotoxicity, reproductive toxicity, and cardiovascular toxicity. Developmental effects include fetal death, impaired immune function and neurotoxicity (NAS 2000).


Forms from mercury, a pollutant from coal-fired power plants and other sources. Methylmercury accumulates in seafood and harms brain development and function.

Methylmercury has been found in 88 of the 90 people tested in EWG/Commonweal studies.

Results for Methylmercury

in whole blood (wet weight)

Showing results from EWG/Commonweal Study #1, industrial chemicals and pesticides in adults, Adult Minority Leader Report, EWG/Commonweal Study #4, industrial chemicals and pesticides in cord blood, Pollution in Minority Newborns, EWG Study #6, consumer product chemicals in mothers and daughters, EWG Study #5, Teflon and mercury in blood in adults and teens, EWG/Commonweal Study #7, consumer product chemicals in adults and teens, EWG Study #3, industrial chemicals and pesticides in adults, Other Body Burden Studies, Pets Project

EWG/Commonweal results

  • geometric mean: 1.61 ug/L (wet weight) in whole blood
  • found in 88 of 90 people in the group
ug/L (wet weight) in whole blood 25.9

Methylmercury results