chemical information
CAS RN:

4376-18-5

Chemical Class:

Phthalates

Found in these people:

Sara Corbett, Nicholas, May, Participant #1, Ann Hunter-Welborn, Participant #18, Participant #2, Participant #20, Jessica Welborn, Irene Crowe, Martha Davis, Emily Sayrs, Participant #6, Annette Gellert, Anonymous Adult, Erin Schrode, Hope Atkins, Rizza Alcaria, Alex Wells, Anonymous Teen 9, Emma Spencer, Christa Heffron, Natalie Klapper, Anonymous Teen 11, Sarah Oswald, Laurie Mittelmann, Donalin Cazeau, Jenny Gilbertson

Found in these locations:

NY, USA; CA, USA; Encinitas, CA; VA, USA; CO, USA; San Francisco, CA; Washington, DC; Littleton, CO; MD, USA; Belvedere, CA; New York, NY; Ross, CA; Tuolumne, CA; Manteca, CA; Winchester, MA; Portland, OR; Los Angeles, CA; Palm Beach Gardens, FL; North Caldwell, NJ; Dorchester, MA; Novato, CA

Exposure routes:

Breakdown product of chemical used in cosmetics, paint, plastic, food packaging, and other common consumer products.


Summary

Found within many consumer products, phthalates are industrial plasticizers that impart flexibility and resilience to plastic, among other uses. Monomethyl phthalate (mMeP) is a metabolite, or breakdown product, of dimethyl phthalate (DMP), used in insect repellant, plastic, and as a rocket propellant (EWG 2003; Wolff 2007). Exposure to dimethyl phthalate occurs through direct use of products containing this chemical, as well as through inhalation of contaminated air (CDC 2005).

In September 2000, scientists from the Centers for Disease Control and Prevention (CDC) conducted the first accurate measurements of human phthalate exposures, and reported finding phthalates in every one of 289 people tested, at surprisingly high levels (Blount 2000). The latest exposure study from CDC indicates that mMeP is a common contaminant of the human body (CDC 2005). Measurements of mMeP in the urine of over 2,500 Americans indicate that women are more exposed than men, and younger children (ages 6-11) are more exposed than older children (ages 12-19), who are in turn more exposed than adults (CDC 2005). In a recent study of girls age 6 to 8 spearheaded by Mount Sinai School of Medicine, this particular phthalate metabolite was found in 18 of 90 girls tested (Wolff 2007). The European Union has banned use of some phthalates in cosmetics and other consumer products, in response to concerns about exposure as well as toxicity.

Phthalates are potent toxins to the male reproductive system. One recent study found suggestive evidence that high levels of mMeP are associated with altered sperm morphology in adult men (Duty 2003). High levels of other phthalate metabolites are associated with reduced levels of sperm motility and concentration, and alterations in hormone levels in adult men (Duty 2003, 2004, 2005). A recent study of 134 births found marked differences in the reproductive systems of baby boys whose mothers had the highest measurements of other phthalate metabolites during pregnancy (Swan 2005). A second study indicates that these mothers' phthalate exposures were not extreme, but rather were typical for about one-quarter of all U.S. women (Marsee 2006). Further research documented decreased testosterone levels among baby boys exposed to mMeP in their mother's breast milk (Main 2006).

In addition to this epidemiological research on humans, laboratory studies indicate phthalates cause a broad range of birth defects and lifelong reproductive impairments in animals exposed in utero and shortly after birth (Marsman 1995; Wine 1997; Ema 1998; Mylchreest 1998, 1999, 2000; Gray 1999). Phthalate exposures damage the testes, prostate gland, epididymis, penis, and seminal vesicles in laboratory animals (Mylchreest 1998); most of these effects persist throughout the animal's life. Monomethyl phthalate and its parent compound, dimethyl phthalate (DMP), have not been as thoroughly studied as other phthalates, but existing studies show that DMP may cause liver toxicity (Field 1993). DMP and mMeP do not appear to be as potent as other phthalates in causing male reproductive tract toxicity (Gray 2000).


Monomethyl phthalate

Breakdown product of dimethyl phthalate, used in insect repellant, plastic, rocket propellant. Fetal and adult exposures are linked to male reproductive problems in people.

Monomethyl phthalate has been found in 34 of the 74 people tested in EWG/Commonweal studies. It has also been found in 4,274 of the 5,479 people tested in CDC biomonitoring studies.


Top health concerns for Monomethyl phthalate (References)

health concern or target organ weight of evidence
Endocrine systemunknown

Other health concerns for Monomethyl phthalate (References)

health concern or target organ weight of evidence
Gastrointestinal (including liver)unknown


Results for Monomethyl phthalate

in urine

Showing results from EWG/Commonweal Study #7, consumer product chemicals in adults and teens, EWG Study #10, cosmetic chemicals in teens, EWG Study #6, consumer product chemicals in mothers and daughters, Pets Project, Dateline NBC Families, Dateline NBC Families, EWG Study #8, chemicals in mother and 2 children

EWG/Commonweal results

  • geometric mean: 3.97 ug/g creatinine in urine
  • found in 34 of 74 people in the group

CDC biomonitoring results

  • geometric mean: 1.31 ug/g creatinine in urine
  • found in 4274 of 5479 people in the group
0 ug/g creatinine in urine 887


Monomethyl phthalate results


Detailed toxicity classifications (References)

classification governing entity/references
Endocrine system toxicity - weight of evidence unknown/unassessedMain KM, Mortensen GK, Kaleva MM, Boisen KA, Damgaard IN, Chellakooty M, et al. 2006. Human breast milk contamination with phthalates and alterations of endogenous reproductive hormones in infants three months of age. Environ Health Perspect 114(2): 270-276.
Gastrointestinal system toxicity - weight of evidence unknown/unassessedField EA, Price CJ, Sleet RB, George JD, Marr MC, Myers CB, et al. 1993. Developmental toxicity evaluation of diethyl and dimethyl phthalate in rats. Teratology 48(1): 33-44.
Endocrine system toxicity - weight of evidence unknown/unassessedMain KM, Mortensen GK, Kaleva MM, Boisen KA, Damgaard IN, Chellakooty M, et al. 2006. Human breast milk contamination with phthalates and alterations of endogenous reproductive hormones in infants three months of age. Environ Health Perspect 114(2): 270-276.