Figure 3: Dose-response relationship of urinary mono-n-octyl phthalate
with self-reported eye affliction/retinopathy in NHANES 2001-2010 participants.
All metabolites were detectable in urine in > 95% of participants except MiNP and MOP (mono-n-octyl phthalate
), which were measurable in 49% and 34% of men, respectively.
All the HMW phthalate metabolites, except mono-isononyl phthalate (MiNP), mono-cyclohexyl phthalate (MCHP), and mono-n-octyl phthalate
(MOP) were detectable in the majority of samples.
Samples were analyzed for content of 14 phthalate metabolites: monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), MEHP, mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-n-octyl phthalate
(MOP), mono(3-carboxypropyl) phthalate (MCPP), MiNP, mono(hydroxy-isononyl) phthalate (MHiNP), mono(oxo-isononyl) phthalate (MOiNP) and mono(carboxy-isooctyl) phthalate (MCiOP) by liquid chromatography tandem mass spectrometry (LC-MS/MS) with preceding enzymatic deconjugation followed by solid phase extraction.
In an in vitro study of the human epithelial cell line A549, several phthalate metabolites, including MEHP and mono-n-octyl phthalate
, but not MBzP, stimulated the production of the nonallergic, proinflammatory cytokine IL-8 (Jepsen et al.
Data for other phthalate metabolites--monocyclohexyl phthalate, mono-n-octyl phthalate
, and monoisononyl phthalate--were also available for the three NHANES cycles.
Eight phthalate monoesters--MBzP, MBP, MEP, MEHP, monomethyl phthalate (MMP), mono-n-octyl phthalate
(MOP), mono-3-methyl-5-dimethylhexyl phthalate (MINP), and monocyclohexyl phthalate (MCHP)--were measured in each spot urine sample using an analytical approach developed at the CDC (Silva et al.
We infrequently detected monoisononyl phthalate, mono-cyclohexyl phthalate, and mono-n-octyl phthalate, suggesting that human exposures to di-isononyl phthalate, dioctylphthalate, and dicyclohexyl phthalate, respectively, are lower than those listed above, of the pathways, routes of exposure, or pharmacokinetic factors such as absorption, distribution, metabolism, and elimination are different.
We calculated the geometric means (GMs) and distribution percentiles for both the volume-based and creatinine-corrected concentrations using the survey sampling weights, which take into account the unequal selection probabilities caused by the cluster design and the planned oversampling of certain subgroups The analytical limits of detection (LODs) were MEP, 1.0 [micro]g/L; MBP, 0.6 [micro]g/L; MBzP 0.8 [micro]g/L; MEHP, 1.2 [micro]g/L; mono-cyclohexyl phthalate (MCHP), 0.7 [micro]g/L; mono-n-octyl phthalate (MOP), 0.9 [micro]g/L; and mono-3-methyl-5-dimethylhexyl phthalate [monoisononyl phthalate (MINP)], 0.8 [micro]g/L.
Eight monoester metabolites were quantified, including monoethylhexyl phthalate (mEHP), monobenzyl phthalate (mBzP), monobutyl phthalate (mBP), monoethyl phthalate (mEP), monocyclohexyl phthalate (mCHP), mono-n-octyl phthalate
(mOP), mono-isononyl phthalate (mINP), and monomethyl phthalate (mMP).
The metabolites measured are monoethyl phthalate (MEP), MBP, MBzP, mono-n-octyl phthalate
, MEHP, and mono-3-methyl-5-dimethylhexyl phthalate (monoisononyl, MINP).