chemical information
CAS RN:
22967-92-6
Chemical Class:
Found in these people:
Baby #5, Participant #10, Participant #2, Judi Shils, U.S. Representative Louise Slaughter, Participant #6, Baby #4, Baby #10, Kathy Fowler, Baby #3, Margie Roswell, Charlotte Brody, Baby #1, Baby #7, Alicia Wittink, Davis Baltz, Baby #9, Anonymous Adult 1, Kelsey Wirth, Baby #6, Baby #8, Emily Sayrs, Nina Damato, Jessica Welborn, Heather Gellert, Baby #2, Landon Gellert, Lexi Rome, Participant #8, Participant #18, Bill Moyers, Stephanie Berger, Ann Hunter-Welborn, Nora Pouillon, Anonymous Adult, Sharyle Patton, Participant #1, Michael Goodstein, Winsome McIntosh, Participant #2, Irene Crowe, Participant #20, Lynde Uihlein, Lucy Waletsky, Annette Gellert, Martha Davis, Fred Gellert, Adelaide Gomer, Jesse Johnson, Michael Lerner, Andrea Martin, Vivian Chang, Dr. Beverly Wright, Jennifer Hill-Kelley, Jean Salone
Found in these locations:
CA, USA; Silver Spring, MD; Ross, CA; Upstate New York, NY; MD, USA; Rockville, MD; Baltimore, MD; Round Hill, VA; Washington, DC; Berkeley, CA; Cambridge, MA; Littleton, CO; San Francisco, CA; Belvedere, CA; Mill Valley, CA; VA, USA; NJ, USA; Bethesda, MD; Encinitas, CA; Bolinas, CA; CO, USA; Milwaukee, WI; Pleasantville, NY; Ithaca, NY; Sausalito, CA; Oakland, CA; New Orleans, LA; Green Bay, WI; Corpus Christi, TX
Exposure routes:
Primarily from dietary sources, particularly seafood.
Summary
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).
Methylmercury
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.
Top health concerns for Methylmercury (References)
| health concern or target organ | weight of evidence |
| Birth defects and developmental delays | probable |
| Brain and nervous system | strong |
Other health concerns for Methylmercury (References)
| health concern or target organ | weight of evidence |
| Cancer | limited |
| Persistent, accumulates in wildlife and/or people | probable |
| Immune system (including sensitization and allergies) | limited |
| Kidney and renal system | limited |
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, Minority Cord Blood, 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
| 0 | ug/L (wet weight) in whole blood | 25.9 |
 | ||
Methylmercury results
Detailed toxicity classifications (References)
| classification | governing entity/references |
| Group C: Possible human carcinogen (EPA classification) | EPA Integrated Risk Information System (IRIS) |
| Known to be neurotoxic to humans, suspected developmental neurotoxin | Chemicals known to be neurotoxic to humans |
| Persistent, bioaccumulative toxicant under Canada's Accelerated Reduction/Elimination of Toxics program - targeted for elimination or reduction | EC (Environment Canada). 1994. Accelerated Reduction/Elimination of Toxics (ARET). ARET substance list of persistent, bioaccumulative and toxic chemicals. |
| Immunotoxicity hazards: suspected | IPCS |
| Kidney toxicity hazards: suspected | MERCK |
| Developmental toxicity hazards: recognized | P65 |
| Cancer hazards: recognized | P65-MC |
