Urinary excretion of phthalate metabolites in 129 healthy Danish children and adolescents: estimation of daily phthalate intake.

BACKGROUND: Phthalates are a group of chemicals with widespread use in the industrial production of numerous consumer products. They are suspected to be involved in male reproductive health problems and have also been associated with several other health problems in children including obesity and asthma.

OBJECTIVES: To study the urinary excretion of phthalate metabolites in Danish children recruited from the general population, and to estimate the daily intake of phthalates in this segment of the population.

METHOD: One 24 h urine sample and to consecutive first morning urine samples were collected from 129 healthy Danish children and adolescents (range 6-21 yrs). The concentrations of 11 phthalate metabolites of 5 different phthalate diesters were analyzed by liquid chromatography-tandem mass spectrometry.

RESULTS: The analyzed metabolites were detectable in almost all 24h urine samples. The median concentrations of monoethyl phthalate (MEP), monobenzyl phthalate (MBzP) and the sums of the two monobutyl phthalate isoforms (∑MBP(i+n)), metabolites of di-(2-ethylhexyl) phthalate (∑DEHPm) and of di-iso-nonyl phthalate (∑DiNPm) were 29, 17, 111, 107 and 31 ng/mL, respectively. The youngest children were generally more exposed to phthalates than older children and adolescents (except diethyl phthalate (DEP)). Boys were more exposed than girls. The median estimated daily intake of phthalate diesters was: 4.29 (dibutyl phthalate isoforms (DBP(i+n))), 4.04 (DEHP), 1.70 (DiNP), 1.09 (DEP) and 0.62 (butylbenzyl phthalate (BBzP)), all calculated as μg/kg body weight/24h. Between 40% and 48% of the absolute amount of phthalate metabolites excreted over 24h were excreted in first morning urine voids.

CONCLUSION: Danish children are exposed simultaneously to multiple phthalates. The highest exposure levels were found for DBP(i+n) and DEHP, which in animal models are the known most potent anti-androgenic phthalates. The combined exposure to the two isoforms of DBP, which have similar endocrine-disrupting potencies in animal models, exceeded the TDI for di-n-butyl phthalate (DnBP) in several of the younger children.