Exposure to di-2-ethylhexyl terephthalate in a convenience sample of U.S. adults from 2000 to 2016.
Di-2-ethylhexyl terephthalate (DEHTP), a structural isomer of di-2-ethylhexyl phthalate (DEHP), is a plasticizer used in a variety of commercial applications, but data on Americans' exposure to DEHTP do not exist. We investigated the exposure to DEHTP in a convenience group of U.S. adults by analyzing urine collected anonymously in 2000 (N = 44), 2009 (N = 61), 2011 (N = 81), 2013 (N = 92), and 2016 (N = 149) for two major DEHTP oxidative metabolites: mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP) and mono-2-ethyl-5-hydroxyhexyl terephthalate (MEHHTP). For comparison, we also quantified the analogous DEHP metabolites mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP) and mono-2-ethyl-5-carboxypentyl phthalate (MECPP). We detected MECPTP, MEHHP, and MECPP in all samples collected in 2016 with geometric means of 13.1, 4.1, and 6.7 ng/mL, respectively; we detected MEHHTP in 91% of the samples (geometric mean = 3.1 ng/mL). Concentrations of MECPTP correlated well with those of MEHHTP (R2= 0.8, p < 0.001), but did not significantly correlate with those of MEHHP (p > 0.05) suggesting different sources of exposure to DEHP and DEHTP. We also evaluated the fraction of the metabolites eliminated in their free (i.e., unconjugated) form. The median percent of unconjugated species was lower for the DEHP metabolites (MECPP [45.5%], MEHHP [1.9%]) compared to the DEHTP metabolites (MECPTP [98.8%], MEHHTP [21.2%]). Contrary to the downward trend from 2000 to 2016 in urinary concentrations of MEHHP and MECPP, we observed an upward trend for MEHHTP and MECPTP. These preliminary data suggest that exposure to DEHTP may be on the rise. Nevertheless, general population exposure data using MEHHTP and MECPTP as exposure biomarkers would increase our understanding of exposure to DEHTP, one of the known DEHP alternatives.
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA. zca2@cdc.gov.
Manori J
MJ
Silva
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA.
Lee-Yang
LY
Wong
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA.
Ella
E
Samandar
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA.
James L
JL
Preau
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA.
Antonia M
AM
Calafat
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., NE, Mailstop F53, Atlanta, GA, 30341, USA.
Xiaoyun
X
Ye
D000328:Adult; D015415:Biomarkers / Q000652:urine; D000074341:Dietary Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D010795:Phthalic Acids / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D014481:United States
D015415:Biomarkers; D010795:Phthalic Acids; C053316:di-(2-ethylhexyl) terephthalate
DEHP; DEHTP; Di-2-ethylhexyl phthalate; Di-2-ethylhexyl terephthalate; Exposure; Oxidative metabolites; Plasticizers