title: Selecting adequate exposure biomarkers of diisononyl and diisodecyl phthalates: data from the 2005-2006 National Health and Nutrition Examination Survey.
abstract: BACKGROUND
  High-molecular-weight phthalates, such as diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), are used primarily as polyvinyl chloride plasticizers.
  
  
  OBJECTIVE
  We assessed exposure to DINP and DIDP in a representative sample of persons ≥ 6 years of age in the U.S. general population from the 2005-2006 National Health and Nutrition Examination Survey (NHANES).
  
  
  METHODS
  We analyzed 2,548 urine samples by using online solid-phase extraction coupled to isotope dilution high-performance liquid chromatography-tandem mass spectrometry.
  
  
  RESULTS
  We detected monocarboxyisooctyl phthalate (MCOP), a metabolite of DINP, and monocarboxyisononyl phthalate (MCNP), a metabolite of DIDP, in 95.2% and 89.9% of the samples, respectively. We detected monoisononyl phthalate (MNP), a minor metabolite of DINP, much less frequently (12.9%) and at concentration ranges (> 0.8 µg/L-148.1 µg/L) much lower than MCOP (> 0.7 µg/L- 4,961 µg/L). Adjusted geometric mean concentrations of MCOP and MCNP were significantly higher (p < 0.01) among children than among adolescents and adults.
  
  
  CONCLUSIONS
  The general U.S. population, including children, was exposed to DINP and DIDP. In previous NHANES cycles, the occurrence of human exposure to DINP by using MNP as the sole urinary biomarker has been underestimated, thus illustrating the importance of selecting the most adequate biomarkers for exposure assessment.
authors.affiliation: Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA. Acalafat@cdc.gov
authors.forename: Antonia M
authors.initials: AM
authors.lastname: Calafat
authors.forename: Lee-Yang
authors.initials: LY
authors.lastname: Wong
authors.forename: Manori J
authors.initials: MJ
authors.lastname: Silva
authors.forename: Ella
authors.initials: E
authors.lastname: Samandar
authors.forename: James L
authors.initials: JL
authors.lastname: Preau
authors.forename: Lily T
authors.initials: LT
authors.lastname: Jia
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D002648:Child; D004781:Environmental Exposure / Q000032:analysis* / Q000592:standards; D004784:Environmental Monitoring / Q000379:methods / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D010795:Phthalic Acids / Q000592:standards / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010795:Phthalic Acids; C012125:diisononyl phthalate; C042080:diisodecyl phthalate