Concentrations of phthalate metabolites in milk, urine, saliva, and Serum of lactating North Carolina women.
BACKGROUND
Phthalates are ubiquitous in the environment, but concentrations in multiple media from breast-feeding U.S. women have not been evaluated.


OBJECTIVE
The objective of this study was to accurately measure and compare the concentrations of oxidative monoester phthalate metabolites in milk and surrogate fluids (serum, saliva, and urine) of 33 lactating North Carolina women.


METHODS
We analyzed serum, saliva, urine, and milk for the oxidative phthalate metabolites mono(3-carboxypropyl) phthalate, mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono(2-ethyl-5-hydroxyhexyl) phthalate, and mono(2-ethyl-5-oxohexyl) phthalate using isotope-dilution high-performance liquid chromatography tandem mass spectroscopy. Because only urine lacks esterases, we analyzed it for the hydrolytic phthalate monoesters.


RESULTS
We detected phthalate metabolites in few milk (< 10%) and saliva samples. MECPP was detected in > 80% of serum samples, but other metabolites were less common (3-22%). Seven of the 10 urinary metabolites were detectable in > or = 85% of samples. Monoethyl phthalate had the highest mean concentration in urine. Metabolite concentrations differed by body fluid (urine > serum > milk and saliva). Questionnaire data suggest that frequent nail polish use, immunoglobulin A, and fasting serum glucose and triglyceride levels were increased among women with higher concentrations of urinary and/or serum phthalate metabolites; motor vehicle age was inversely correlated with certain urinary phthalate concentrations.


CONCLUSIONS
Our data suggest that phthalate metabolites are most frequently detected in urine of lactating women and are less often detected in serum, milk, or saliva. Urinary phthalate concentrations reflect maternal exposure and do not represent the concentrations of oxidative metabolites in other body fluids, especially milk.
Hines
Erin P
EP
Reproductive Toxicology Division, Developmental Biology Branch, Office of Research and Development, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
Calafat
Antonia M
AM
Silva
Manori J
MJ
Mendola
Pauline
P
Fenton
Suzanne E
SE
D005260:Female; D006801:Humans; D007774:Lactation; D018811:Maternal Exposure; D008895:Milk, Human / Q000737:chemistry*; D009657:North Carolina; D010795:Phthalic Acids / Q000032:analysis* / Q000097:blood / Q000652:urine; D011247:Pregnancy; D012463:Saliva / Q000737:chemistry*; D011795:Surveys and Questionnaires
D010795:Phthalic Acids